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1 | \input texinfo @c -*-texinfo-*- |
2 | ||
3 | @c %**start of header | |
4 | @setfilename libgomp.info | |
5 | @settitle GNU libgomp | |
6 | @c %**end of header | |
7 | ||
8 | ||
9 | @copying | |
74d5206f | 10 | Copyright @copyright{} 2006-2023 Free Software Foundation, Inc. |
d77de738 ML |
11 | |
12 | Permission is granted to copy, distribute and/or modify this document | |
13 | under the terms of the GNU Free Documentation License, Version 1.3 or | |
14 | any later version published by the Free Software Foundation; with the | |
15 | Invariant Sections being ``Funding Free Software'', the Front-Cover | |
16 | texts being (a) (see below), and with the Back-Cover Texts being (b) | |
17 | (see below). A copy of the license is included in the section entitled | |
18 | ``GNU Free Documentation License''. | |
19 | ||
20 | (a) The FSF's Front-Cover Text is: | |
21 | ||
22 | A GNU Manual | |
23 | ||
24 | (b) The FSF's Back-Cover Text is: | |
25 | ||
26 | You have freedom to copy and modify this GNU Manual, like GNU | |
27 | software. Copies published by the Free Software Foundation raise | |
28 | funds for GNU development. | |
29 | @end copying | |
30 | ||
31 | @ifinfo | |
32 | @dircategory GNU Libraries | |
33 | @direntry | |
34 | * libgomp: (libgomp). GNU Offloading and Multi Processing Runtime Library. | |
35 | @end direntry | |
36 | ||
37 | This manual documents libgomp, the GNU Offloading and Multi Processing | |
38 | Runtime library. This is the GNU implementation of the OpenMP and | |
39 | OpenACC APIs for parallel and accelerator programming in C/C++ and | |
40 | Fortran. | |
41 | ||
42 | Published by the Free Software Foundation | |
43 | 51 Franklin Street, Fifth Floor | |
44 | Boston, MA 02110-1301 USA | |
45 | ||
46 | @insertcopying | |
47 | @end ifinfo | |
48 | ||
49 | ||
50 | @setchapternewpage odd | |
51 | ||
52 | @titlepage | |
53 | @title GNU Offloading and Multi Processing Runtime Library | |
54 | @subtitle The GNU OpenMP and OpenACC Implementation | |
55 | @page | |
56 | @vskip 0pt plus 1filll | |
57 | @comment For the @value{version-GCC} Version* | |
58 | @sp 1 | |
59 | Published by the Free Software Foundation @* | |
60 | 51 Franklin Street, Fifth Floor@* | |
61 | Boston, MA 02110-1301, USA@* | |
62 | @sp 1 | |
63 | @insertcopying | |
64 | @end titlepage | |
65 | ||
66 | @summarycontents | |
67 | @contents | |
68 | @page | |
69 | ||
70 | ||
71 | @node Top, Enabling OpenMP | |
72 | @top Introduction | |
73 | @cindex Introduction | |
74 | ||
75 | This manual documents the usage of libgomp, the GNU Offloading and | |
76 | Multi Processing Runtime Library. This includes the GNU | |
77 | implementation of the @uref{https://www.openmp.org, OpenMP} Application | |
78 | Programming Interface (API) for multi-platform shared-memory parallel | |
79 | programming in C/C++ and Fortran, and the GNU implementation of the | |
80 | @uref{https://www.openacc.org, OpenACC} Application Programming | |
81 | Interface (API) for offloading of code to accelerator devices in C/C++ | |
82 | and Fortran. | |
83 | ||
84 | Originally, libgomp implemented the GNU OpenMP Runtime Library. Based | |
85 | on this, support for OpenACC and offloading (both OpenACC and OpenMP | |
86 | 4's target construct) has been added later on, and the library's name | |
87 | changed to GNU Offloading and Multi Processing Runtime Library. | |
88 | ||
89 | ||
90 | ||
91 | @comment | |
92 | @comment When you add a new menu item, please keep the right hand | |
93 | @comment aligned to the same column. Do not use tabs. This provides | |
94 | @comment better formatting. | |
95 | @comment | |
96 | @menu | |
97 | * Enabling OpenMP:: How to enable OpenMP for your applications. | |
98 | * OpenMP Implementation Status:: List of implemented features by OpenMP version | |
99 | * OpenMP Runtime Library Routines: Runtime Library Routines. | |
100 | The OpenMP runtime application programming | |
101 | interface. | |
102 | * OpenMP Environment Variables: Environment Variables. | |
103 | Influencing OpenMP runtime behavior with | |
104 | environment variables. | |
105 | * Enabling OpenACC:: How to enable OpenACC for your | |
106 | applications. | |
107 | * OpenACC Runtime Library Routines:: The OpenACC runtime application | |
108 | programming interface. | |
109 | * OpenACC Environment Variables:: Influencing OpenACC runtime behavior with | |
110 | environment variables. | |
111 | * CUDA Streams Usage:: Notes on the implementation of | |
112 | asynchronous operations. | |
113 | * OpenACC Library Interoperability:: OpenACC library interoperability with the | |
114 | NVIDIA CUBLAS library. | |
115 | * OpenACC Profiling Interface:: | |
116 | * OpenMP-Implementation Specifics:: Notes specifics of this OpenMP | |
117 | implementation | |
118 | * Offload-Target Specifics:: Notes on offload-target specific internals | |
119 | * The libgomp ABI:: Notes on the external ABI presented by libgomp. | |
120 | * Reporting Bugs:: How to report bugs in the GNU Offloading and | |
121 | Multi Processing Runtime Library. | |
122 | * Copying:: GNU general public license says | |
123 | how you can copy and share libgomp. | |
124 | * GNU Free Documentation License:: | |
125 | How you can copy and share this manual. | |
126 | * Funding:: How to help assure continued work for free | |
127 | software. | |
128 | * Library Index:: Index of this documentation. | |
129 | @end menu | |
130 | ||
131 | ||
132 | @c --------------------------------------------------------------------- | |
133 | @c Enabling OpenMP | |
134 | @c --------------------------------------------------------------------- | |
135 | ||
136 | @node Enabling OpenMP | |
137 | @chapter Enabling OpenMP | |
138 | ||
643a5223 TB |
139 | To activate the OpenMP extensions for C/C++ and Fortran, the compile-time |
140 | flag @option{-fopenmp} must be specified. For C and C++, this enables | |
5648446c | 141 | the handling of the OpenMP directives using @code{#pragma omp} and the |
643a5223 TB |
142 | @code{[[omp::directive(...)]]}, @code{[[omp::sequence(...)]]} and |
143 | @code{[[omp::decl(...)]]} attributes. For Fortran, it enables for | |
144 | free source form the @code{!$omp} sentinel for directives and the | |
145 | @code{!$} conditional compilation sentinel and for fixed source form the | |
146 | @code{c$omp}, @code{*$omp} and @code{!$omp} sentinels for directives and | |
147 | the @code{c$}, @code{*$} and @code{!$} conditional compilation sentinels. | |
148 | The flag also arranges for automatic linking of the OpenMP runtime library | |
d77de738 ML |
149 | (@ref{Runtime Library Routines}). |
150 | ||
643a5223 TB |
151 | The @option{-fopenmp-simd} flag can be used to enable a subset of |
152 | OpenMP directives that do not require the linking of either the | |
153 | OpenMP runtime library or the POSIX threads library. | |
154 | ||
d77de738 ML |
155 | A complete description of all OpenMP directives may be found in the |
156 | @uref{https://www.openmp.org, OpenMP Application Program Interface} manuals. | |
157 | See also @ref{OpenMP Implementation Status}. | |
158 | ||
159 | ||
160 | @c --------------------------------------------------------------------- | |
161 | @c OpenMP Implementation Status | |
162 | @c --------------------------------------------------------------------- | |
163 | ||
164 | @node OpenMP Implementation Status | |
165 | @chapter OpenMP Implementation Status | |
166 | ||
167 | @menu | |
168 | * OpenMP 4.5:: Feature completion status to 4.5 specification | |
169 | * OpenMP 5.0:: Feature completion status to 5.0 specification | |
170 | * OpenMP 5.1:: Feature completion status to 5.1 specification | |
171 | * OpenMP 5.2:: Feature completion status to 5.2 specification | |
fcddf7ce | 172 | * OpenMP Technical Report 12:: Feature completion status to second 6.0 preview |
d77de738 ML |
173 | @end menu |
174 | ||
175 | The @code{_OPENMP} preprocessor macro and Fortran's @code{openmp_version} | |
176 | parameter, provided by @code{omp_lib.h} and the @code{omp_lib} module, have | |
177 | the value @code{201511} (i.e. OpenMP 4.5). | |
178 | ||
179 | @node OpenMP 4.5 | |
180 | @section OpenMP 4.5 | |
181 | ||
182 | The OpenMP 4.5 specification is fully supported. | |
183 | ||
184 | @node OpenMP 5.0 | |
185 | @section OpenMP 5.0 | |
186 | ||
187 | @unnumberedsubsec New features listed in Appendix B of the OpenMP specification | |
188 | @c This list is sorted as in OpenMP 5.1's B.3 not as in OpenMP 5.0's B.2 | |
189 | ||
190 | @multitable @columnfractions .60 .10 .25 | |
191 | @headitem Description @tab Status @tab Comments | |
192 | @item Array shaping @tab N @tab | |
193 | @item Array sections with non-unit strides in C and C++ @tab N @tab | |
194 | @item Iterators @tab Y @tab | |
195 | @item @code{metadirective} directive @tab N @tab | |
196 | @item @code{declare variant} directive | |
197 | @tab P @tab @emph{simd} traits not handled correctly | |
2cd0689a | 198 | @item @var{target-offload-var} ICV and @code{OMP_TARGET_OFFLOAD} |
d77de738 | 199 | env variable @tab Y @tab |
2cd0689a | 200 | @item Nested-parallel changes to @var{max-active-levels-var} ICV @tab Y @tab |
d77de738 | 201 | @item @code{requires} directive @tab P |
8c2fc744 | 202 | @tab complete but no non-host device provides @code{unified_shared_memory} |
d77de738 | 203 | @item @code{teams} construct outside an enclosing target region @tab Y @tab |
85da0b40 TB |
204 | @item Non-rectangular loop nests @tab P |
205 | @tab Full support for C/C++, partial for Fortran | |
206 | (@uref{https://gcc.gnu.org/PR110735,PR110735}) | |
d77de738 ML |
207 | @item @code{!=} as relational-op in canonical loop form for C/C++ @tab Y @tab |
208 | @item @code{nonmonotonic} as default loop schedule modifier for worksharing-loop | |
209 | constructs @tab Y @tab | |
87f9b6c2 | 210 | @item Collapse of associated loops that are imperfectly nested loops @tab Y @tab |
d77de738 ML |
211 | @item Clauses @code{if}, @code{nontemporal} and @code{order(concurrent)} in |
212 | @code{simd} construct @tab Y @tab | |
213 | @item @code{atomic} constructs in @code{simd} @tab Y @tab | |
214 | @item @code{loop} construct @tab Y @tab | |
215 | @item @code{order(concurrent)} clause @tab Y @tab | |
216 | @item @code{scan} directive and @code{in_scan} modifier for the | |
217 | @code{reduction} clause @tab Y @tab | |
218 | @item @code{in_reduction} clause on @code{task} constructs @tab Y @tab | |
219 | @item @code{in_reduction} clause on @code{target} constructs @tab P | |
220 | @tab @code{nowait} only stub | |
221 | @item @code{task_reduction} clause with @code{taskgroup} @tab Y @tab | |
222 | @item @code{task} modifier to @code{reduction} clause @tab Y @tab | |
223 | @item @code{affinity} clause to @code{task} construct @tab Y @tab Stub only | |
224 | @item @code{detach} clause to @code{task} construct @tab Y @tab | |
225 | @item @code{omp_fulfill_event} runtime routine @tab Y @tab | |
226 | @item @code{reduction} and @code{in_reduction} clauses on @code{taskloop} | |
227 | and @code{taskloop simd} constructs @tab Y @tab | |
228 | @item @code{taskloop} construct cancelable by @code{cancel} construct | |
229 | @tab Y @tab | |
230 | @item @code{mutexinoutset} @emph{dependence-type} for @code{depend} clause | |
231 | @tab Y @tab | |
232 | @item Predefined memory spaces, memory allocators, allocator traits | |
13c3e29d | 233 | @tab Y @tab See also @ref{Memory allocation} |
d77de738 | 234 | @item Memory management routines @tab Y @tab |
969f5c3e | 235 | @item @code{allocate} directive @tab P @tab Only C and Fortran, only stack variables |
d77de738 ML |
236 | @item @code{allocate} clause @tab P @tab Initial support |
237 | @item @code{use_device_addr} clause on @code{target data} @tab Y @tab | |
f84fdb13 | 238 | @item @code{ancestor} modifier on @code{device} clause @tab Y @tab |
d77de738 ML |
239 | @item Implicit declare target directive @tab Y @tab |
240 | @item Discontiguous array section with @code{target update} construct | |
241 | @tab N @tab | |
242 | @item C/C++'s lvalue expressions in @code{to}, @code{from} | |
243 | and @code{map} clauses @tab N @tab | |
244 | @item C/C++'s lvalue expressions in @code{depend} clauses @tab Y @tab | |
245 | @item Nested @code{declare target} directive @tab Y @tab | |
246 | @item Combined @code{master} constructs @tab Y @tab | |
247 | @item @code{depend} clause on @code{taskwait} @tab Y @tab | |
248 | @item Weak memory ordering clauses on @code{atomic} and @code{flush} construct | |
249 | @tab Y @tab | |
250 | @item @code{hint} clause on the @code{atomic} construct @tab Y @tab Stub only | |
251 | @item @code{depobj} construct and depend objects @tab Y @tab | |
252 | @item Lock hints were renamed to synchronization hints @tab Y @tab | |
253 | @item @code{conditional} modifier to @code{lastprivate} clause @tab Y @tab | |
254 | @item Map-order clarifications @tab P @tab | |
255 | @item @code{close} @emph{map-type-modifier} @tab Y @tab | |
256 | @item Mapping C/C++ pointer variables and to assign the address of | |
257 | device memory mapped by an array section @tab P @tab | |
258 | @item Mapping of Fortran pointer and allocatable variables, including pointer | |
259 | and allocatable components of variables | |
260 | @tab P @tab Mapping of vars with allocatable components unsupported | |
261 | @item @code{defaultmap} extensions @tab Y @tab | |
262 | @item @code{declare mapper} directive @tab N @tab | |
263 | @item @code{omp_get_supported_active_levels} routine @tab Y @tab | |
264 | @item Runtime routines and environment variables to display runtime thread | |
265 | affinity information @tab Y @tab | |
266 | @item @code{omp_pause_resource} and @code{omp_pause_resource_all} runtime | |
267 | routines @tab Y @tab | |
268 | @item @code{omp_get_device_num} runtime routine @tab Y @tab | |
269 | @item OMPT interface @tab N @tab | |
270 | @item OMPD interface @tab N @tab | |
271 | @end multitable | |
272 | ||
273 | @unnumberedsubsec Other new OpenMP 5.0 features | |
274 | ||
275 | @multitable @columnfractions .60 .10 .25 | |
276 | @headitem Description @tab Status @tab Comments | |
277 | @item Supporting C++'s range-based for loop @tab Y @tab | |
278 | @end multitable | |
279 | ||
280 | ||
281 | @node OpenMP 5.1 | |
282 | @section OpenMP 5.1 | |
283 | ||
284 | @unnumberedsubsec New features listed in Appendix B of the OpenMP specification | |
285 | ||
286 | @multitable @columnfractions .60 .10 .25 | |
287 | @headitem Description @tab Status @tab Comments | |
288 | @item OpenMP directive as C++ attribute specifiers @tab Y @tab | |
289 | @item @code{omp_all_memory} reserved locator @tab Y @tab | |
290 | @item @emph{target_device trait} in OpenMP Context @tab N @tab | |
291 | @item @code{target_device} selector set in context selectors @tab N @tab | |
292 | @item C/C++'s @code{declare variant} directive: elision support of | |
293 | preprocessed code @tab N @tab | |
294 | @item @code{declare variant}: new clauses @code{adjust_args} and | |
295 | @code{append_args} @tab N @tab | |
296 | @item @code{dispatch} construct @tab N @tab | |
297 | @item device-specific ICV settings with environment variables @tab Y @tab | |
eda38850 | 298 | @item @code{assume} and @code{assumes} directives @tab Y @tab |
d77de738 ML |
299 | @item @code{nothing} directive @tab Y @tab |
300 | @item @code{error} directive @tab Y @tab | |
301 | @item @code{masked} construct @tab Y @tab | |
302 | @item @code{scope} directive @tab Y @tab | |
303 | @item Loop transformation constructs @tab N @tab | |
304 | @item @code{strict} modifier in the @code{grainsize} and @code{num_tasks} | |
305 | clauses of the @code{taskloop} construct @tab Y @tab | |
1a554a2c | 306 | @item @code{align} clause in @code{allocate} directive @tab P |
969f5c3e | 307 | @tab Only C and Fortran (and only stack variables) |
b2e1c49b | 308 | @item @code{align} modifier in @code{allocate} clause @tab Y @tab |
d77de738 ML |
309 | @item @code{thread_limit} clause to @code{target} construct @tab Y @tab |
310 | @item @code{has_device_addr} clause to @code{target} construct @tab Y @tab | |
311 | @item Iterators in @code{target update} motion clauses and @code{map} | |
312 | clauses @tab N @tab | |
313 | @item Indirect calls to the device version of a procedure or function in | |
a49c7d31 | 314 | @code{target} regions @tab P @tab Only C and C++ |
d77de738 ML |
315 | @item @code{interop} directive @tab N @tab |
316 | @item @code{omp_interop_t} object support in runtime routines @tab N @tab | |
317 | @item @code{nowait} clause in @code{taskwait} directive @tab Y @tab | |
318 | @item Extensions to the @code{atomic} directive @tab Y @tab | |
319 | @item @code{seq_cst} clause on a @code{flush} construct @tab Y @tab | |
320 | @item @code{inoutset} argument to the @code{depend} clause @tab Y @tab | |
321 | @item @code{private} and @code{firstprivate} argument to @code{default} | |
322 | clause in C and C++ @tab Y @tab | |
4ede915d | 323 | @item @code{present} argument to @code{defaultmap} clause @tab Y @tab |
d77de738 ML |
324 | @item @code{omp_set_num_teams}, @code{omp_set_teams_thread_limit}, |
325 | @code{omp_get_max_teams}, @code{omp_get_teams_thread_limit} runtime | |
326 | routines @tab Y @tab | |
327 | @item @code{omp_target_is_accessible} runtime routine @tab Y @tab | |
328 | @item @code{omp_target_memcpy_async} and @code{omp_target_memcpy_rect_async} | |
329 | runtime routines @tab Y @tab | |
330 | @item @code{omp_get_mapped_ptr} runtime routine @tab Y @tab | |
331 | @item @code{omp_calloc}, @code{omp_realloc}, @code{omp_aligned_alloc} and | |
332 | @code{omp_aligned_calloc} runtime routines @tab Y @tab | |
333 | @item @code{omp_alloctrait_key_t} enum: @code{omp_atv_serialized} added, | |
334 | @code{omp_atv_default} changed @tab Y @tab | |
335 | @item @code{omp_display_env} runtime routine @tab Y @tab | |
336 | @item @code{ompt_scope_endpoint_t} enum: @code{ompt_scope_beginend} @tab N @tab | |
337 | @item @code{ompt_sync_region_t} enum additions @tab N @tab | |
338 | @item @code{ompt_state_t} enum: @code{ompt_state_wait_barrier_implementation} | |
339 | and @code{ompt_state_wait_barrier_teams} @tab N @tab | |
340 | @item @code{ompt_callback_target_data_op_emi_t}, | |
341 | @code{ompt_callback_target_emi_t}, @code{ompt_callback_target_map_emi_t} | |
342 | and @code{ompt_callback_target_submit_emi_t} @tab N @tab | |
343 | @item @code{ompt_callback_error_t} type @tab N @tab | |
344 | @item @code{OMP_PLACES} syntax extensions @tab Y @tab | |
345 | @item @code{OMP_NUM_TEAMS} and @code{OMP_TEAMS_THREAD_LIMIT} environment | |
346 | variables @tab Y @tab | |
347 | @end multitable | |
348 | ||
349 | @unnumberedsubsec Other new OpenMP 5.1 features | |
350 | ||
351 | @multitable @columnfractions .60 .10 .25 | |
352 | @headitem Description @tab Status @tab Comments | |
353 | @item Support of strictly structured blocks in Fortran @tab Y @tab | |
354 | @item Support of structured block sequences in C/C++ @tab Y @tab | |
355 | @item @code{unconstrained} and @code{reproducible} modifiers on @code{order} | |
356 | clause @tab Y @tab | |
357 | @item Support @code{begin/end declare target} syntax in C/C++ @tab Y @tab | |
358 | @item Pointer predetermined firstprivate getting initialized | |
359 | to address of matching mapped list item per 5.1, Sect. 2.21.7.2 @tab N @tab | |
360 | @item For Fortran, diagnose placing declarative before/between @code{USE}, | |
361 | @code{IMPORT}, and @code{IMPLICIT} as invalid @tab N @tab | |
eda38850 | 362 | @item Optional comma between directive and clause in the @code{#pragma} form @tab Y @tab |
a49c7d31 | 363 | @item @code{indirect} clause in @code{declare target} @tab P @tab Only C and C++ |
c16e85d7 | 364 | @item @code{device_type(nohost)}/@code{device_type(host)} for variables @tab N @tab |
4ede915d TB |
365 | @item @code{present} modifier to the @code{map}, @code{to} and @code{from} |
366 | clauses @tab Y @tab | |
d77de738 ML |
367 | @end multitable |
368 | ||
369 | ||
370 | @node OpenMP 5.2 | |
371 | @section OpenMP 5.2 | |
372 | ||
373 | @unnumberedsubsec New features listed in Appendix B of the OpenMP specification | |
374 | ||
375 | @multitable @columnfractions .60 .10 .25 | |
376 | @headitem Description @tab Status @tab Comments | |
2cd0689a | 377 | @item @code{omp_in_explicit_task} routine and @var{explicit-task-var} ICV |
d77de738 ML |
378 | @tab Y @tab |
379 | @item @code{omp}/@code{ompx}/@code{omx} sentinels and @code{omp_}/@code{ompx_} | |
380 | namespaces @tab N/A | |
381 | @tab warning for @code{ompx/omx} sentinels@footnote{The @code{ompx} | |
382 | sentinel as C/C++ pragma and C++ attributes are warned for with | |
383 | @code{-Wunknown-pragmas} (implied by @code{-Wall}) and @code{-Wattributes} | |
384 | (enabled by default), respectively; for Fortran free-source code, there is | |
385 | a warning enabled by default and, for fixed-source code, the @code{omx} | |
386 | sentinel is warned for with with @code{-Wsurprising} (enabled by | |
387 | @code{-Wall}). Unknown clauses are always rejected with an error.} | |
091b6dbc | 388 | @item Clauses on @code{end} directive can be on directive @tab Y @tab |
0698c9fd TB |
389 | @item @code{destroy} clause with destroy-var argument on @code{depobj} |
390 | @tab N @tab | |
d77de738 ML |
391 | @item Deprecation of no-argument @code{destroy} clause on @code{depobj} |
392 | @tab N @tab | |
393 | @item @code{linear} clause syntax changes and @code{step} modifier @tab Y @tab | |
394 | @item Deprecation of minus operator for reductions @tab N @tab | |
395 | @item Deprecation of separating @code{map} modifiers without comma @tab N @tab | |
396 | @item @code{declare mapper} with iterator and @code{present} modifiers | |
397 | @tab N @tab | |
398 | @item If a matching mapped list item is not found in the data environment, the | |
b25ea7ab | 399 | pointer retains its original value @tab Y @tab |
d77de738 ML |
400 | @item New @code{enter} clause as alias for @code{to} on declare target directive |
401 | @tab Y @tab | |
402 | @item Deprecation of @code{to} clause on declare target directive @tab N @tab | |
403 | @item Extended list of directives permitted in Fortran pure procedures | |
2df7e451 | 404 | @tab Y @tab |
d77de738 ML |
405 | @item New @code{allocators} directive for Fortran @tab N @tab |
406 | @item Deprecation of @code{allocate} directive for Fortran | |
407 | allocatables/pointers @tab N @tab | |
408 | @item Optional paired @code{end} directive with @code{dispatch} @tab N @tab | |
409 | @item New @code{memspace} and @code{traits} modifiers for @code{uses_allocators} | |
410 | @tab N @tab | |
411 | @item Deprecation of traits array following the allocator_handle expression in | |
412 | @code{uses_allocators} @tab N @tab | |
413 | @item New @code{otherwise} clause as alias for @code{default} on metadirectives | |
414 | @tab N @tab | |
415 | @item Deprecation of @code{default} clause on metadirectives @tab N @tab | |
416 | @item Deprecation of delimited form of @code{declare target} @tab N @tab | |
417 | @item Reproducible semantics changed for @code{order(concurrent)} @tab N @tab | |
418 | @item @code{allocate} and @code{firstprivate} clauses on @code{scope} | |
419 | @tab Y @tab | |
420 | @item @code{ompt_callback_work} @tab N @tab | |
9f80367e | 421 | @item Default map-type for the @code{map} clause in @code{target enter/exit data} |
d77de738 ML |
422 | @tab Y @tab |
423 | @item New @code{doacross} clause as alias for @code{depend} with | |
424 | @code{source}/@code{sink} modifier @tab Y @tab | |
425 | @item Deprecation of @code{depend} with @code{source}/@code{sink} modifier | |
426 | @tab N @tab | |
427 | @item @code{omp_cur_iteration} keyword @tab Y @tab | |
428 | @end multitable | |
429 | ||
430 | @unnumberedsubsec Other new OpenMP 5.2 features | |
431 | ||
432 | @multitable @columnfractions .60 .10 .25 | |
433 | @headitem Description @tab Status @tab Comments | |
434 | @item For Fortran, optional comma between directive and clause @tab N @tab | |
435 | @item Conforming device numbers and @code{omp_initial_device} and | |
436 | @code{omp_invalid_device} enum/PARAMETER @tab Y @tab | |
2cd0689a | 437 | @item Initial value of @var{default-device-var} ICV with |
18c8b56c | 438 | @code{OMP_TARGET_OFFLOAD=mandatory} @tab Y @tab |
0698c9fd | 439 | @item @code{all} as @emph{implicit-behavior} for @code{defaultmap} @tab Y @tab |
d77de738 ML |
440 | @item @emph{interop_types} in any position of the modifier list for the @code{init} clause |
441 | of the @code{interop} construct @tab N @tab | |
a49c7d31 KCY |
442 | @item Invoke virtual member functions of C++ objects created on the host device |
443 | on other devices @tab N @tab | |
d77de738 ML |
444 | @end multitable |
445 | ||
446 | ||
fcddf7ce TB |
447 | @node OpenMP Technical Report 12 |
448 | @section OpenMP Technical Report 12 | |
c16e85d7 | 449 | |
fcddf7ce | 450 | Technical Report (TR) 12 is the second preview for OpenMP 6.0. |
c16e85d7 TB |
451 | |
452 | @unnumberedsubsec New features listed in Appendix B of the OpenMP specification | |
453 | @multitable @columnfractions .60 .10 .25 | |
454 | @item Features deprecated in versions 5.2, 5.1 and 5.0 were removed | |
455 | @tab N/A @tab Backward compatibility | |
fcddf7ce TB |
456 | @item Full support for C23 was added @tab P @tab |
457 | @item Full support for C++23 was added @tab P @tab | |
c16e85d7 TB |
458 | @item @code{_ALL} suffix to the device-scope environment variables |
459 | @tab P @tab Host device number wrongly accepted | |
fcddf7ce TB |
460 | @item @code{num_threads} now accepts a list @tab N @tab |
461 | @item Supporting increments with abstract names in @code{OMP_PLACES} @tab N @tab | |
462 | @item Extension of @code{OMP_DEFAULT_DEVICE} and new | |
463 | @code{OMP_AVAILABLE_DEVICES} environment vars @tab N @tab | |
464 | @item New @code{OMP_THREADS_RESERVE} environment variable @tab N @tab | |
465 | @item The @code{decl} attribute was added to the C++ attribute syntax | |
466 | @tab Y @tab | |
467 | @item The OpenMP directive syntax was extended to include C 23 attribute | |
468 | specifiers @tab Y @tab | |
469 | @item All inarguable clauses take now an optional Boolean argument @tab N @tab | |
c16e85d7 TB |
470 | @item For Fortran, @emph{locator list} can be also function reference with |
471 | data pointer result @tab N @tab | |
fcddf7ce TB |
472 | @item Concept of @emph{assumed-size arrays} in C and C++ |
473 | @tab N @tab | |
474 | @item @emph{directive-name-modifier} accepted in all clauses @tab N @tab | |
475 | @item For Fortran, atomic with BLOCK construct and, for C/C++, with | |
476 | unlimited curly braces supported @tab N @tab | |
477 | @item For Fortran, atomic compare with storing the comparison result | |
478 | @tab N @tab | |
479 | @item New @code{looprange} clause @tab N @tab | |
c16e85d7 TB |
480 | @item Ref-count change for @code{use_device_ptr}/@code{use_device_addr} |
481 | @tab N @tab | |
fcddf7ce | 482 | @item Support for inductions @tab N @tab |
c16e85d7 TB |
483 | @item Implicit reduction identifiers of C++ classes |
484 | @tab N @tab | |
485 | @item Change of the @emph{map-type} property from @emph{ultimate} to | |
486 | @emph{default} @tab N @tab | |
fcddf7ce TB |
487 | @item @code{self} modifier to @code{map} and @code{self} as |
488 | @code{defaultmap} argument @tab N @tab | |
c16e85d7 TB |
489 | @item Mapping of @emph{assumed-size arrays} in C, C++ and Fortran |
490 | @tab N @tab | |
491 | @item @code{groupprivate} directive @tab N @tab | |
fcddf7ce | 492 | @item @code{local} clause to @code{declare target} directive @tab N @tab |
c16e85d7 TB |
493 | @item @code{part_size} allocator trait @tab N @tab |
494 | @item @code{pin_device}, @code{preferred_device} and @code{target_access} | |
495 | allocator traits | |
496 | @tab N @tab | |
497 | @item @code{access} allocator trait changes @tab N @tab | |
498 | @item Extension of @code{interop} operation of @code{append_args}, allowing all | |
499 | modifiers of the @code{init} clause | |
9f80367e | 500 | @tab N @tab |
c16e85d7 | 501 | @item @code{interop} clause to @code{dispatch} @tab N @tab |
fcddf7ce TB |
502 | @item @code{message} and @code{severity} calauses to @code{parallel} directive |
503 | @tab N @tab | |
504 | @item @code{self} clause to @code{requires} directive @tab N @tab | |
505 | @item @code{no_openmp_constructs} assumptions clause @tab N @tab | |
506 | @item @code{reverse} loop-transformation construct @tab N @tab | |
507 | @item @code{interchange} loop-transformation construct @tab N @tab | |
508 | @item @code{fuse} loop-transformation construct @tab N @tab | |
c16e85d7 TB |
509 | @item @code{apply} code to loop-transforming constructs @tab N @tab |
510 | @item @code{omp_curr_progress_width} identifier @tab N @tab | |
511 | @item @code{safesync} clause to the @code{parallel} construct @tab N @tab | |
512 | @item @code{omp_get_max_progress_width} runtime routine @tab N @tab | |
8da7476c | 513 | @item @code{strict} modifier keyword to @code{num_threads} @tab N @tab |
fcddf7ce TB |
514 | @item @code{atomic} permitted in a construct with @code{order(concurrent)} |
515 | @tab N @tab | |
516 | @item @code{coexecute} directive for Fortran @tab N @tab | |
517 | @item Fortran DO CONCURRENT as associated loop in a @code{loop} construct | |
518 | @tab N @tab | |
519 | @item @code{threadset} clause in task-generating constructs @tab N @tab | |
520 | @item @code{nowait} clause with reverse-offload @code{target} directives | |
521 | @tab N @tab | |
522 | @item Boolean argument to @code{nowait} and @code{nogroup} may be non constant | |
523 | @tab N @tab | |
c16e85d7 | 524 | @item @code{memscope} clause to @code{atomic} and @code{flush} @tab N @tab |
fcddf7ce TB |
525 | @item @code{omp_is_free_agent} and @code{omp_ancestor_is_free_agent} routines |
526 | @tab N @tab | |
527 | @item @code{omp_target_memset} and @code{omp_target_memset_rect_async} routines | |
528 | @tab N @tab | |
c16e85d7 TB |
529 | @item Routines for obtaining memory spaces/allocators for shared/device memory |
530 | @tab N @tab | |
531 | @item @code{omp_get_memspace_num_resources} routine @tab N @tab | |
532 | @item @code{omp_get_submemspace} routine @tab N @tab | |
fcddf7ce TB |
533 | @item @code{ompt_target_data_transfer} and @code{ompt_target_data_transfer_async} |
534 | values in @code{ompt_target_data_op_t} enum @tab N @tab | |
c16e85d7 | 535 | @item @code{ompt_get_buffer_limits} OMPT routine @tab N @tab |
c16e85d7 TB |
536 | @end multitable |
537 | ||
fcddf7ce | 538 | @unnumberedsubsec Other new TR 12 features |
c16e85d7 TB |
539 | @multitable @columnfractions .60 .10 .25 |
540 | @item Relaxed Fortran restrictions to the @code{aligned} clause @tab N @tab | |
541 | @item Mapping lambda captures @tab N @tab | |
fcddf7ce | 542 | @item New @code{omp_pause_stop_tool} constant for omp_pause_resource @tab N @tab |
c16e85d7 TB |
543 | @end multitable |
544 | ||
545 | ||
546 | ||
d77de738 ML |
547 | @c --------------------------------------------------------------------- |
548 | @c OpenMP Runtime Library Routines | |
549 | @c --------------------------------------------------------------------- | |
550 | ||
551 | @node Runtime Library Routines | |
552 | @chapter OpenMP Runtime Library Routines | |
553 | ||
506f068e TB |
554 | The runtime routines described here are defined by Section 18 of the OpenMP |
555 | specification in version 5.2. | |
d77de738 ML |
556 | |
557 | @menu | |
506f068e TB |
558 | * Thread Team Routines:: |
559 | * Thread Affinity Routines:: | |
560 | * Teams Region Routines:: | |
561 | * Tasking Routines:: | |
562 | @c * Resource Relinquishing Routines:: | |
563 | * Device Information Routines:: | |
e0786ba6 | 564 | * Device Memory Routines:: |
506f068e TB |
565 | * Lock Routines:: |
566 | * Timing Routines:: | |
567 | * Event Routine:: | |
568 | @c * Interoperability Routines:: | |
971f119f | 569 | * Memory Management Routines:: |
506f068e TB |
570 | @c * Tool Control Routine:: |
571 | @c * Environment Display Routine:: | |
572 | @end menu | |
d77de738 | 573 | |
506f068e TB |
574 | |
575 | ||
576 | @node Thread Team Routines | |
577 | @section Thread Team Routines | |
578 | ||
579 | Routines controlling threads in the current contention group. | |
580 | They have C linkage and do not throw exceptions. | |
581 | ||
582 | @menu | |
583 | * omp_set_num_threads:: Set upper team size limit | |
d77de738 | 584 | * omp_get_num_threads:: Size of the active team |
506f068e | 585 | * omp_get_max_threads:: Maximum number of threads of parallel region |
d77de738 ML |
586 | * omp_get_thread_num:: Current thread ID |
587 | * omp_in_parallel:: Whether a parallel region is active | |
d77de738 | 588 | * omp_set_dynamic:: Enable/disable dynamic teams |
506f068e TB |
589 | * omp_get_dynamic:: Dynamic teams setting |
590 | * omp_get_cancellation:: Whether cancellation support is enabled | |
d77de738 | 591 | * omp_set_nested:: Enable/disable nested parallel regions |
506f068e | 592 | * omp_get_nested:: Nested parallel regions |
d77de738 | 593 | * omp_set_schedule:: Set the runtime scheduling method |
506f068e TB |
594 | * omp_get_schedule:: Obtain the runtime scheduling method |
595 | * omp_get_teams_thread_limit:: Maximum number of threads imposed by teams | |
596 | * omp_get_supported_active_levels:: Maximum number of active regions supported | |
597 | * omp_set_max_active_levels:: Limits the number of active parallel regions | |
598 | * omp_get_max_active_levels:: Current maximum number of active regions | |
599 | * omp_get_level:: Number of parallel regions | |
600 | * omp_get_ancestor_thread_num:: Ancestor thread ID | |
601 | * omp_get_team_size:: Number of threads in a team | |
602 | * omp_get_active_level:: Number of active parallel regions | |
603 | @end menu | |
d77de738 | 604 | |
d77de738 | 605 | |
d77de738 | 606 | |
506f068e TB |
607 | @node omp_set_num_threads |
608 | @subsection @code{omp_set_num_threads} -- Set upper team size limit | |
609 | @table @asis | |
610 | @item @emph{Description}: | |
611 | Specifies the number of threads used by default in subsequent parallel | |
612 | sections, if those do not specify a @code{num_threads} clause. The | |
613 | argument of @code{omp_set_num_threads} shall be a positive integer. | |
d77de738 | 614 | |
506f068e TB |
615 | @item @emph{C/C++}: |
616 | @multitable @columnfractions .20 .80 | |
617 | @item @emph{Prototype}: @tab @code{void omp_set_num_threads(int num_threads);} | |
618 | @end multitable | |
d77de738 | 619 | |
506f068e TB |
620 | @item @emph{Fortran}: |
621 | @multitable @columnfractions .20 .80 | |
622 | @item @emph{Interface}: @tab @code{subroutine omp_set_num_threads(num_threads)} | |
623 | @item @tab @code{integer, intent(in) :: num_threads} | |
624 | @end multitable | |
d77de738 | 625 | |
506f068e TB |
626 | @item @emph{See also}: |
627 | @ref{OMP_NUM_THREADS}, @ref{omp_get_num_threads}, @ref{omp_get_max_threads} | |
d77de738 | 628 | |
506f068e TB |
629 | @item @emph{Reference}: |
630 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.1. | |
631 | @end table | |
d77de738 ML |
632 | |
633 | ||
506f068e TB |
634 | |
635 | @node omp_get_num_threads | |
636 | @subsection @code{omp_get_num_threads} -- Size of the active team | |
d77de738 ML |
637 | @table @asis |
638 | @item @emph{Description}: | |
506f068e TB |
639 | Returns the number of threads in the current team. In a sequential section of |
640 | the program @code{omp_get_num_threads} returns 1. | |
d77de738 | 641 | |
506f068e TB |
642 | The default team size may be initialized at startup by the |
643 | @env{OMP_NUM_THREADS} environment variable. At runtime, the size | |
644 | of the current team may be set either by the @code{NUM_THREADS} | |
645 | clause or by @code{omp_set_num_threads}. If none of the above were | |
646 | used to define a specific value and @env{OMP_DYNAMIC} is disabled, | |
647 | one thread per CPU online is used. | |
648 | ||
649 | @item @emph{C/C++}: | |
d77de738 | 650 | @multitable @columnfractions .20 .80 |
506f068e | 651 | @item @emph{Prototype}: @tab @code{int omp_get_num_threads(void);} |
d77de738 ML |
652 | @end multitable |
653 | ||
654 | @item @emph{Fortran}: | |
655 | @multitable @columnfractions .20 .80 | |
506f068e | 656 | @item @emph{Interface}: @tab @code{integer function omp_get_num_threads()} |
d77de738 ML |
657 | @end multitable |
658 | ||
659 | @item @emph{See also}: | |
506f068e | 660 | @ref{omp_get_max_threads}, @ref{omp_set_num_threads}, @ref{OMP_NUM_THREADS} |
d77de738 ML |
661 | |
662 | @item @emph{Reference}: | |
506f068e | 663 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.2. |
d77de738 ML |
664 | @end table |
665 | ||
666 | ||
667 | ||
506f068e TB |
668 | @node omp_get_max_threads |
669 | @subsection @code{omp_get_max_threads} -- Maximum number of threads of parallel region | |
d77de738 ML |
670 | @table @asis |
671 | @item @emph{Description}: | |
506f068e TB |
672 | Return the maximum number of threads used for the current parallel region |
673 | that does not use the clause @code{num_threads}. | |
d77de738 | 674 | |
506f068e | 675 | @item @emph{C/C++}: |
d77de738 | 676 | @multitable @columnfractions .20 .80 |
506f068e | 677 | @item @emph{Prototype}: @tab @code{int omp_get_max_threads(void);} |
d77de738 ML |
678 | @end multitable |
679 | ||
680 | @item @emph{Fortran}: | |
681 | @multitable @columnfractions .20 .80 | |
506f068e | 682 | @item @emph{Interface}: @tab @code{integer function omp_get_max_threads()} |
d77de738 ML |
683 | @end multitable |
684 | ||
685 | @item @emph{See also}: | |
506f068e | 686 | @ref{omp_set_num_threads}, @ref{omp_set_dynamic}, @ref{omp_get_thread_limit} |
d77de738 ML |
687 | |
688 | @item @emph{Reference}: | |
506f068e | 689 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.3. |
d77de738 ML |
690 | @end table |
691 | ||
692 | ||
693 | ||
506f068e TB |
694 | @node omp_get_thread_num |
695 | @subsection @code{omp_get_thread_num} -- Current thread ID | |
d77de738 ML |
696 | @table @asis |
697 | @item @emph{Description}: | |
506f068e TB |
698 | Returns a unique thread identification number within the current team. |
699 | In a sequential parts of the program, @code{omp_get_thread_num} | |
700 | always returns 0. In parallel regions the return value varies | |
701 | from 0 to @code{omp_get_num_threads}-1 inclusive. The return | |
702 | value of the primary thread of a team is always 0. | |
d77de738 ML |
703 | |
704 | @item @emph{C/C++}: | |
705 | @multitable @columnfractions .20 .80 | |
506f068e | 706 | @item @emph{Prototype}: @tab @code{int omp_get_thread_num(void);} |
d77de738 ML |
707 | @end multitable |
708 | ||
709 | @item @emph{Fortran}: | |
710 | @multitable @columnfractions .20 .80 | |
506f068e | 711 | @item @emph{Interface}: @tab @code{integer function omp_get_thread_num()} |
d77de738 ML |
712 | @end multitable |
713 | ||
714 | @item @emph{See also}: | |
506f068e | 715 | @ref{omp_get_num_threads}, @ref{omp_get_ancestor_thread_num} |
d77de738 ML |
716 | |
717 | @item @emph{Reference}: | |
506f068e | 718 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.4. |
d77de738 ML |
719 | @end table |
720 | ||
721 | ||
722 | ||
506f068e TB |
723 | @node omp_in_parallel |
724 | @subsection @code{omp_in_parallel} -- Whether a parallel region is active | |
d77de738 ML |
725 | @table @asis |
726 | @item @emph{Description}: | |
506f068e TB |
727 | This function returns @code{true} if currently running in parallel, |
728 | @code{false} otherwise. Here, @code{true} and @code{false} represent | |
729 | their language-specific counterparts. | |
d77de738 ML |
730 | |
731 | @item @emph{C/C++}: | |
732 | @multitable @columnfractions .20 .80 | |
506f068e | 733 | @item @emph{Prototype}: @tab @code{int omp_in_parallel(void);} |
d77de738 ML |
734 | @end multitable |
735 | ||
736 | @item @emph{Fortran}: | |
737 | @multitable @columnfractions .20 .80 | |
506f068e | 738 | @item @emph{Interface}: @tab @code{logical function omp_in_parallel()} |
d77de738 ML |
739 | @end multitable |
740 | ||
d77de738 | 741 | @item @emph{Reference}: |
506f068e | 742 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.6. |
d77de738 ML |
743 | @end table |
744 | ||
745 | ||
506f068e TB |
746 | @node omp_set_dynamic |
747 | @subsection @code{omp_set_dynamic} -- Enable/disable dynamic teams | |
d77de738 ML |
748 | @table @asis |
749 | @item @emph{Description}: | |
506f068e TB |
750 | Enable or disable the dynamic adjustment of the number of threads |
751 | within a team. The function takes the language-specific equivalent | |
752 | of @code{true} and @code{false}, where @code{true} enables dynamic | |
753 | adjustment of team sizes and @code{false} disables it. | |
d77de738 | 754 | |
506f068e | 755 | @item @emph{C/C++}: |
d77de738 | 756 | @multitable @columnfractions .20 .80 |
506f068e | 757 | @item @emph{Prototype}: @tab @code{void omp_set_dynamic(int dynamic_threads);} |
d77de738 ML |
758 | @end multitable |
759 | ||
760 | @item @emph{Fortran}: | |
761 | @multitable @columnfractions .20 .80 | |
506f068e TB |
762 | @item @emph{Interface}: @tab @code{subroutine omp_set_dynamic(dynamic_threads)} |
763 | @item @tab @code{logical, intent(in) :: dynamic_threads} | |
d77de738 ML |
764 | @end multitable |
765 | ||
766 | @item @emph{See also}: | |
506f068e | 767 | @ref{OMP_DYNAMIC}, @ref{omp_get_dynamic} |
d77de738 ML |
768 | |
769 | @item @emph{Reference}: | |
506f068e | 770 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.7. |
d77de738 ML |
771 | @end table |
772 | ||
773 | ||
774 | ||
775 | @node omp_get_dynamic | |
506f068e | 776 | @subsection @code{omp_get_dynamic} -- Dynamic teams setting |
d77de738 ML |
777 | @table @asis |
778 | @item @emph{Description}: | |
779 | This function returns @code{true} if enabled, @code{false} otherwise. | |
780 | Here, @code{true} and @code{false} represent their language-specific | |
781 | counterparts. | |
782 | ||
783 | The dynamic team setting may be initialized at startup by the | |
784 | @env{OMP_DYNAMIC} environment variable or at runtime using | |
785 | @code{omp_set_dynamic}. If undefined, dynamic adjustment is | |
786 | disabled by default. | |
787 | ||
788 | @item @emph{C/C++}: | |
789 | @multitable @columnfractions .20 .80 | |
790 | @item @emph{Prototype}: @tab @code{int omp_get_dynamic(void);} | |
791 | @end multitable | |
792 | ||
793 | @item @emph{Fortran}: | |
794 | @multitable @columnfractions .20 .80 | |
795 | @item @emph{Interface}: @tab @code{logical function omp_get_dynamic()} | |
796 | @end multitable | |
797 | ||
798 | @item @emph{See also}: | |
799 | @ref{omp_set_dynamic}, @ref{OMP_DYNAMIC} | |
800 | ||
801 | @item @emph{Reference}: | |
802 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.8. | |
803 | @end table | |
804 | ||
805 | ||
806 | ||
506f068e TB |
807 | @node omp_get_cancellation |
808 | @subsection @code{omp_get_cancellation} -- Whether cancellation support is enabled | |
d77de738 ML |
809 | @table @asis |
810 | @item @emph{Description}: | |
506f068e TB |
811 | This function returns @code{true} if cancellation is activated, @code{false} |
812 | otherwise. Here, @code{true} and @code{false} represent their language-specific | |
813 | counterparts. Unless @env{OMP_CANCELLATION} is set true, cancellations are | |
814 | deactivated. | |
d77de738 | 815 | |
506f068e | 816 | @item @emph{C/C++}: |
d77de738 | 817 | @multitable @columnfractions .20 .80 |
506f068e | 818 | @item @emph{Prototype}: @tab @code{int omp_get_cancellation(void);} |
d77de738 ML |
819 | @end multitable |
820 | ||
821 | @item @emph{Fortran}: | |
822 | @multitable @columnfractions .20 .80 | |
506f068e | 823 | @item @emph{Interface}: @tab @code{logical function omp_get_cancellation()} |
d77de738 ML |
824 | @end multitable |
825 | ||
826 | @item @emph{See also}: | |
506f068e | 827 | @ref{OMP_CANCELLATION} |
d77de738 ML |
828 | |
829 | @item @emph{Reference}: | |
506f068e | 830 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.9. |
d77de738 ML |
831 | @end table |
832 | ||
833 | ||
834 | ||
506f068e TB |
835 | @node omp_set_nested |
836 | @subsection @code{omp_set_nested} -- Enable/disable nested parallel regions | |
d77de738 ML |
837 | @table @asis |
838 | @item @emph{Description}: | |
506f068e TB |
839 | Enable or disable nested parallel regions, i.e., whether team members |
840 | are allowed to create new teams. The function takes the language-specific | |
841 | equivalent of @code{true} and @code{false}, where @code{true} enables | |
842 | dynamic adjustment of team sizes and @code{false} disables it. | |
d77de738 | 843 | |
15886c03 | 844 | Enabling nested parallel regions also sets the maximum number of |
506f068e | 845 | active nested regions to the maximum supported. Disabling nested parallel |
15886c03 | 846 | regions sets the maximum number of active nested regions to one. |
506f068e TB |
847 | |
848 | Note that the @code{omp_set_nested} API routine was deprecated | |
849 | in the OpenMP specification 5.2 in favor of @code{omp_set_max_active_levels}. | |
850 | ||
851 | @item @emph{C/C++}: | |
d77de738 | 852 | @multitable @columnfractions .20 .80 |
506f068e | 853 | @item @emph{Prototype}: @tab @code{void omp_set_nested(int nested);} |
d77de738 ML |
854 | @end multitable |
855 | ||
856 | @item @emph{Fortran}: | |
857 | @multitable @columnfractions .20 .80 | |
506f068e TB |
858 | @item @emph{Interface}: @tab @code{subroutine omp_set_nested(nested)} |
859 | @item @tab @code{logical, intent(in) :: nested} | |
d77de738 ML |
860 | @end multitable |
861 | ||
862 | @item @emph{See also}: | |
506f068e TB |
863 | @ref{omp_get_nested}, @ref{omp_set_max_active_levels}, |
864 | @ref{OMP_MAX_ACTIVE_LEVELS}, @ref{OMP_NESTED} | |
d77de738 ML |
865 | |
866 | @item @emph{Reference}: | |
506f068e | 867 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.10. |
d77de738 ML |
868 | @end table |
869 | ||
870 | ||
871 | ||
506f068e TB |
872 | @node omp_get_nested |
873 | @subsection @code{omp_get_nested} -- Nested parallel regions | |
d77de738 ML |
874 | @table @asis |
875 | @item @emph{Description}: | |
506f068e TB |
876 | This function returns @code{true} if nested parallel regions are |
877 | enabled, @code{false} otherwise. Here, @code{true} and @code{false} | |
878 | represent their language-specific counterparts. | |
879 | ||
880 | The state of nested parallel regions at startup depends on several | |
881 | environment variables. If @env{OMP_MAX_ACTIVE_LEVELS} is defined | |
882 | and is set to greater than one, then nested parallel regions will be | |
883 | enabled. If not defined, then the value of the @env{OMP_NESTED} | |
884 | environment variable will be followed if defined. If neither are | |
885 | defined, then if either @env{OMP_NUM_THREADS} or @env{OMP_PROC_BIND} | |
886 | are defined with a list of more than one value, then nested parallel | |
887 | regions are enabled. If none of these are defined, then nested parallel | |
888 | regions are disabled by default. | |
889 | ||
890 | Nested parallel regions can be enabled or disabled at runtime using | |
891 | @code{omp_set_nested}, or by setting the maximum number of nested | |
892 | regions with @code{omp_set_max_active_levels} to one to disable, or | |
893 | above one to enable. | |
894 | ||
895 | Note that the @code{omp_get_nested} API routine was deprecated | |
896 | in the OpenMP specification 5.2 in favor of @code{omp_get_max_active_levels}. | |
897 | ||
898 | @item @emph{C/C++}: | |
899 | @multitable @columnfractions .20 .80 | |
900 | @item @emph{Prototype}: @tab @code{int omp_get_nested(void);} | |
901 | @end multitable | |
902 | ||
903 | @item @emph{Fortran}: | |
904 | @multitable @columnfractions .20 .80 | |
905 | @item @emph{Interface}: @tab @code{logical function omp_get_nested()} | |
906 | @end multitable | |
907 | ||
908 | @item @emph{See also}: | |
909 | @ref{omp_get_max_active_levels}, @ref{omp_set_nested}, | |
910 | @ref{OMP_MAX_ACTIVE_LEVELS}, @ref{OMP_NESTED} | |
911 | ||
912 | @item @emph{Reference}: | |
913 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.11. | |
914 | @end table | |
915 | ||
916 | ||
917 | ||
918 | @node omp_set_schedule | |
919 | @subsection @code{omp_set_schedule} -- Set the runtime scheduling method | |
920 | @table @asis | |
921 | @item @emph{Description}: | |
922 | Sets the runtime scheduling method. The @var{kind} argument can have the | |
923 | value @code{omp_sched_static}, @code{omp_sched_dynamic}, | |
924 | @code{omp_sched_guided} or @code{omp_sched_auto}. Except for | |
925 | @code{omp_sched_auto}, the chunk size is set to the value of | |
926 | @var{chunk_size} if positive, or to the default value if zero or negative. | |
927 | For @code{omp_sched_auto} the @var{chunk_size} argument is ignored. | |
d77de738 ML |
928 | |
929 | @item @emph{C/C++} | |
930 | @multitable @columnfractions .20 .80 | |
506f068e | 931 | @item @emph{Prototype}: @tab @code{void omp_set_schedule(omp_sched_t kind, int chunk_size);} |
d77de738 ML |
932 | @end multitable |
933 | ||
934 | @item @emph{Fortran}: | |
935 | @multitable @columnfractions .20 .80 | |
506f068e TB |
936 | @item @emph{Interface}: @tab @code{subroutine omp_set_schedule(kind, chunk_size)} |
937 | @item @tab @code{integer(kind=omp_sched_kind) kind} | |
938 | @item @tab @code{integer chunk_size} | |
d77de738 ML |
939 | @end multitable |
940 | ||
941 | @item @emph{See also}: | |
506f068e TB |
942 | @ref{omp_get_schedule} |
943 | @ref{OMP_SCHEDULE} | |
d77de738 ML |
944 | |
945 | @item @emph{Reference}: | |
506f068e | 946 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.12. |
d77de738 ML |
947 | @end table |
948 | ||
949 | ||
506f068e TB |
950 | |
951 | @node omp_get_schedule | |
952 | @subsection @code{omp_get_schedule} -- Obtain the runtime scheduling method | |
d77de738 ML |
953 | @table @asis |
954 | @item @emph{Description}: | |
15886c03 TB |
955 | Obtain the runtime scheduling method. The @var{kind} argument is set to |
956 | @code{omp_sched_static}, @code{omp_sched_dynamic}, | |
506f068e TB |
957 | @code{omp_sched_guided} or @code{omp_sched_auto}. The second argument, |
958 | @var{chunk_size}, is set to the chunk size. | |
d77de738 ML |
959 | |
960 | @item @emph{C/C++} | |
961 | @multitable @columnfractions .20 .80 | |
506f068e | 962 | @item @emph{Prototype}: @tab @code{void omp_get_schedule(omp_sched_t *kind, int *chunk_size);} |
d77de738 ML |
963 | @end multitable |
964 | ||
965 | @item @emph{Fortran}: | |
966 | @multitable @columnfractions .20 .80 | |
506f068e TB |
967 | @item @emph{Interface}: @tab @code{subroutine omp_get_schedule(kind, chunk_size)} |
968 | @item @tab @code{integer(kind=omp_sched_kind) kind} | |
969 | @item @tab @code{integer chunk_size} | |
d77de738 ML |
970 | @end multitable |
971 | ||
506f068e TB |
972 | @item @emph{See also}: |
973 | @ref{omp_set_schedule}, @ref{OMP_SCHEDULE} | |
974 | ||
d77de738 | 975 | @item @emph{Reference}: |
506f068e | 976 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.13. |
d77de738 ML |
977 | @end table |
978 | ||
979 | ||
506f068e TB |
980 | @node omp_get_teams_thread_limit |
981 | @subsection @code{omp_get_teams_thread_limit} -- Maximum number of threads imposed by teams | |
d77de738 ML |
982 | @table @asis |
983 | @item @emph{Description}: | |
15886c03 | 984 | Return the maximum number of threads that are able to participate in |
506f068e | 985 | each team created by a teams construct. |
d77de738 ML |
986 | |
987 | @item @emph{C/C++}: | |
988 | @multitable @columnfractions .20 .80 | |
506f068e | 989 | @item @emph{Prototype}: @tab @code{int omp_get_teams_thread_limit(void);} |
d77de738 ML |
990 | @end multitable |
991 | ||
992 | @item @emph{Fortran}: | |
993 | @multitable @columnfractions .20 .80 | |
506f068e | 994 | @item @emph{Interface}: @tab @code{integer function omp_get_teams_thread_limit()} |
d77de738 ML |
995 | @end multitable |
996 | ||
997 | @item @emph{See also}: | |
506f068e | 998 | @ref{omp_set_teams_thread_limit}, @ref{OMP_TEAMS_THREAD_LIMIT} |
d77de738 ML |
999 | |
1000 | @item @emph{Reference}: | |
506f068e | 1001 | @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 3.4.6. |
d77de738 ML |
1002 | @end table |
1003 | ||
1004 | ||
1005 | ||
506f068e TB |
1006 | @node omp_get_supported_active_levels |
1007 | @subsection @code{omp_get_supported_active_levels} -- Maximum number of active regions supported | |
d77de738 ML |
1008 | @table @asis |
1009 | @item @emph{Description}: | |
506f068e TB |
1010 | This function returns the maximum number of nested, active parallel regions |
1011 | supported by this implementation. | |
d77de738 | 1012 | |
506f068e | 1013 | @item @emph{C/C++} |
d77de738 | 1014 | @multitable @columnfractions .20 .80 |
506f068e | 1015 | @item @emph{Prototype}: @tab @code{int omp_get_supported_active_levels(void);} |
d77de738 ML |
1016 | @end multitable |
1017 | ||
1018 | @item @emph{Fortran}: | |
1019 | @multitable @columnfractions .20 .80 | |
506f068e | 1020 | @item @emph{Interface}: @tab @code{integer function omp_get_supported_active_levels()} |
d77de738 ML |
1021 | @end multitable |
1022 | ||
1023 | @item @emph{See also}: | |
506f068e | 1024 | @ref{omp_get_max_active_levels}, @ref{omp_set_max_active_levels} |
d77de738 ML |
1025 | |
1026 | @item @emph{Reference}: | |
506f068e | 1027 | @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.2.15. |
d77de738 ML |
1028 | @end table |
1029 | ||
1030 | ||
1031 | ||
506f068e TB |
1032 | @node omp_set_max_active_levels |
1033 | @subsection @code{omp_set_max_active_levels} -- Limits the number of active parallel regions | |
d77de738 ML |
1034 | @table @asis |
1035 | @item @emph{Description}: | |
506f068e TB |
1036 | This function limits the maximum allowed number of nested, active |
1037 | parallel regions. @var{max_levels} must be less or equal to | |
1038 | the value returned by @code{omp_get_supported_active_levels}. | |
d77de738 | 1039 | |
506f068e TB |
1040 | @item @emph{C/C++} |
1041 | @multitable @columnfractions .20 .80 | |
1042 | @item @emph{Prototype}: @tab @code{void omp_set_max_active_levels(int max_levels);} | |
1043 | @end multitable | |
d77de738 | 1044 | |
506f068e TB |
1045 | @item @emph{Fortran}: |
1046 | @multitable @columnfractions .20 .80 | |
1047 | @item @emph{Interface}: @tab @code{subroutine omp_set_max_active_levels(max_levels)} | |
1048 | @item @tab @code{integer max_levels} | |
1049 | @end multitable | |
d77de738 | 1050 | |
506f068e TB |
1051 | @item @emph{See also}: |
1052 | @ref{omp_get_max_active_levels}, @ref{omp_get_active_level}, | |
1053 | @ref{omp_get_supported_active_levels} | |
2cd0689a | 1054 | |
506f068e TB |
1055 | @item @emph{Reference}: |
1056 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.15. | |
1057 | @end table | |
1058 | ||
1059 | ||
1060 | ||
1061 | @node omp_get_max_active_levels | |
1062 | @subsection @code{omp_get_max_active_levels} -- Current maximum number of active regions | |
1063 | @table @asis | |
1064 | @item @emph{Description}: | |
1065 | This function obtains the maximum allowed number of nested, active parallel regions. | |
1066 | ||
1067 | @item @emph{C/C++} | |
d77de738 | 1068 | @multitable @columnfractions .20 .80 |
506f068e | 1069 | @item @emph{Prototype}: @tab @code{int omp_get_max_active_levels(void);} |
d77de738 ML |
1070 | @end multitable |
1071 | ||
1072 | @item @emph{Fortran}: | |
1073 | @multitable @columnfractions .20 .80 | |
506f068e | 1074 | @item @emph{Interface}: @tab @code{integer function omp_get_max_active_levels()} |
d77de738 ML |
1075 | @end multitable |
1076 | ||
1077 | @item @emph{See also}: | |
506f068e | 1078 | @ref{omp_set_max_active_levels}, @ref{omp_get_active_level} |
d77de738 ML |
1079 | |
1080 | @item @emph{Reference}: | |
506f068e | 1081 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.16. |
d77de738 ML |
1082 | @end table |
1083 | ||
1084 | ||
506f068e TB |
1085 | @node omp_get_level |
1086 | @subsection @code{omp_get_level} -- Obtain the current nesting level | |
d77de738 ML |
1087 | @table @asis |
1088 | @item @emph{Description}: | |
506f068e TB |
1089 | This function returns the nesting level for the parallel blocks, |
1090 | which enclose the calling call. | |
d77de738 | 1091 | |
506f068e | 1092 | @item @emph{C/C++} |
d77de738 | 1093 | @multitable @columnfractions .20 .80 |
506f068e | 1094 | @item @emph{Prototype}: @tab @code{int omp_get_level(void);} |
d77de738 ML |
1095 | @end multitable |
1096 | ||
1097 | @item @emph{Fortran}: | |
1098 | @multitable @columnfractions .20 .80 | |
506f068e | 1099 | @item @emph{Interface}: @tab @code{integer function omp_level()} |
d77de738 ML |
1100 | @end multitable |
1101 | ||
506f068e TB |
1102 | @item @emph{See also}: |
1103 | @ref{omp_get_active_level} | |
1104 | ||
d77de738 | 1105 | @item @emph{Reference}: |
506f068e | 1106 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.17. |
d77de738 ML |
1107 | @end table |
1108 | ||
1109 | ||
1110 | ||
506f068e TB |
1111 | @node omp_get_ancestor_thread_num |
1112 | @subsection @code{omp_get_ancestor_thread_num} -- Ancestor thread ID | |
d77de738 ML |
1113 | @table @asis |
1114 | @item @emph{Description}: | |
506f068e TB |
1115 | This function returns the thread identification number for the given |
1116 | nesting level of the current thread. For values of @var{level} outside | |
1117 | zero to @code{omp_get_level} -1 is returned; if @var{level} is | |
1118 | @code{omp_get_level} the result is identical to @code{omp_get_thread_num}. | |
d77de738 | 1119 | |
506f068e | 1120 | @item @emph{C/C++} |
d77de738 | 1121 | @multitable @columnfractions .20 .80 |
506f068e | 1122 | @item @emph{Prototype}: @tab @code{int omp_get_ancestor_thread_num(int level);} |
d77de738 ML |
1123 | @end multitable |
1124 | ||
1125 | @item @emph{Fortran}: | |
1126 | @multitable @columnfractions .20 .80 | |
506f068e TB |
1127 | @item @emph{Interface}: @tab @code{integer function omp_get_ancestor_thread_num(level)} |
1128 | @item @tab @code{integer level} | |
d77de738 ML |
1129 | @end multitable |
1130 | ||
506f068e TB |
1131 | @item @emph{See also}: |
1132 | @ref{omp_get_level}, @ref{omp_get_thread_num}, @ref{omp_get_team_size} | |
1133 | ||
d77de738 | 1134 | @item @emph{Reference}: |
506f068e | 1135 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.18. |
d77de738 ML |
1136 | @end table |
1137 | ||
1138 | ||
1139 | ||
506f068e TB |
1140 | @node omp_get_team_size |
1141 | @subsection @code{omp_get_team_size} -- Number of threads in a team | |
d77de738 ML |
1142 | @table @asis |
1143 | @item @emph{Description}: | |
506f068e TB |
1144 | This function returns the number of threads in a thread team to which |
1145 | either the current thread or its ancestor belongs. For values of @var{level} | |
1146 | outside zero to @code{omp_get_level}, -1 is returned; if @var{level} is zero, | |
1147 | 1 is returned, and for @code{omp_get_level}, the result is identical | |
1148 | to @code{omp_get_num_threads}. | |
d77de738 ML |
1149 | |
1150 | @item @emph{C/C++}: | |
1151 | @multitable @columnfractions .20 .80 | |
506f068e | 1152 | @item @emph{Prototype}: @tab @code{int omp_get_team_size(int level);} |
d77de738 ML |
1153 | @end multitable |
1154 | ||
1155 | @item @emph{Fortran}: | |
1156 | @multitable @columnfractions .20 .80 | |
506f068e TB |
1157 | @item @emph{Interface}: @tab @code{integer function omp_get_team_size(level)} |
1158 | @item @tab @code{integer level} | |
d77de738 ML |
1159 | @end multitable |
1160 | ||
506f068e TB |
1161 | @item @emph{See also}: |
1162 | @ref{omp_get_num_threads}, @ref{omp_get_level}, @ref{omp_get_ancestor_thread_num} | |
1163 | ||
d77de738 | 1164 | @item @emph{Reference}: |
506f068e | 1165 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.19. |
d77de738 ML |
1166 | @end table |
1167 | ||
1168 | ||
1169 | ||
506f068e TB |
1170 | @node omp_get_active_level |
1171 | @subsection @code{omp_get_active_level} -- Number of parallel regions | |
d77de738 ML |
1172 | @table @asis |
1173 | @item @emph{Description}: | |
506f068e TB |
1174 | This function returns the nesting level for the active parallel blocks, |
1175 | which enclose the calling call. | |
d77de738 | 1176 | |
506f068e | 1177 | @item @emph{C/C++} |
d77de738 | 1178 | @multitable @columnfractions .20 .80 |
506f068e | 1179 | @item @emph{Prototype}: @tab @code{int omp_get_active_level(void);} |
d77de738 ML |
1180 | @end multitable |
1181 | ||
1182 | @item @emph{Fortran}: | |
1183 | @multitable @columnfractions .20 .80 | |
506f068e | 1184 | @item @emph{Interface}: @tab @code{integer function omp_get_active_level()} |
d77de738 ML |
1185 | @end multitable |
1186 | ||
1187 | @item @emph{See also}: | |
506f068e | 1188 | @ref{omp_get_level}, @ref{omp_get_max_active_levels}, @ref{omp_set_max_active_levels} |
d77de738 ML |
1189 | |
1190 | @item @emph{Reference}: | |
506f068e | 1191 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.20. |
d77de738 ML |
1192 | @end table |
1193 | ||
1194 | ||
1195 | ||
506f068e TB |
1196 | @node Thread Affinity Routines |
1197 | @section Thread Affinity Routines | |
1198 | ||
1199 | Routines controlling and accessing thread-affinity policies. | |
1200 | They have C linkage and do not throw exceptions. | |
1201 | ||
1202 | @menu | |
1203 | * omp_get_proc_bind:: Whether threads may be moved between CPUs | |
1204 | @c * omp_get_num_places:: <fixme> | |
1205 | @c * omp_get_place_num_procs:: <fixme> | |
1206 | @c * omp_get_place_proc_ids:: <fixme> | |
1207 | @c * omp_get_place_num:: <fixme> | |
1208 | @c * omp_get_partition_num_places:: <fixme> | |
1209 | @c * omp_get_partition_place_nums:: <fixme> | |
1210 | @c * omp_set_affinity_format:: <fixme> | |
1211 | @c * omp_get_affinity_format:: <fixme> | |
1212 | @c * omp_display_affinity:: <fixme> | |
1213 | @c * omp_capture_affinity:: <fixme> | |
1214 | @end menu | |
1215 | ||
1216 | ||
1217 | ||
d77de738 | 1218 | @node omp_get_proc_bind |
506f068e | 1219 | @subsection @code{omp_get_proc_bind} -- Whether threads may be moved between CPUs |
d77de738 ML |
1220 | @table @asis |
1221 | @item @emph{Description}: | |
1222 | This functions returns the currently active thread affinity policy, which is | |
1223 | set via @env{OMP_PROC_BIND}. Possible values are @code{omp_proc_bind_false}, | |
1224 | @code{omp_proc_bind_true}, @code{omp_proc_bind_primary}, | |
1225 | @code{omp_proc_bind_master}, @code{omp_proc_bind_close} and @code{omp_proc_bind_spread}, | |
1226 | where @code{omp_proc_bind_master} is an alias for @code{omp_proc_bind_primary}. | |
1227 | ||
1228 | @item @emph{C/C++}: | |
1229 | @multitable @columnfractions .20 .80 | |
1230 | @item @emph{Prototype}: @tab @code{omp_proc_bind_t omp_get_proc_bind(void);} | |
1231 | @end multitable | |
1232 | ||
1233 | @item @emph{Fortran}: | |
1234 | @multitable @columnfractions .20 .80 | |
1235 | @item @emph{Interface}: @tab @code{integer(kind=omp_proc_bind_kind) function omp_get_proc_bind()} | |
1236 | @end multitable | |
1237 | ||
1238 | @item @emph{See also}: | |
1239 | @ref{OMP_PROC_BIND}, @ref{OMP_PLACES}, @ref{GOMP_CPU_AFFINITY}, | |
1240 | ||
1241 | @item @emph{Reference}: | |
1242 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.22. | |
1243 | @end table | |
1244 | ||
1245 | ||
1246 | ||
506f068e TB |
1247 | @node Teams Region Routines |
1248 | @section Teams Region Routines | |
d77de738 | 1249 | |
506f068e TB |
1250 | Routines controlling the league of teams that are executed in a @code{teams} |
1251 | region. They have C linkage and do not throw exceptions. | |
d77de738 | 1252 | |
506f068e TB |
1253 | @menu |
1254 | * omp_get_num_teams:: Number of teams | |
1255 | * omp_get_team_num:: Get team number | |
1256 | * omp_set_num_teams:: Set upper teams limit for teams region | |
1257 | * omp_get_max_teams:: Maximum number of teams for teams region | |
1258 | * omp_set_teams_thread_limit:: Set upper thread limit for teams construct | |
1259 | * omp_get_thread_limit:: Maximum number of threads | |
1260 | @end menu | |
d77de738 | 1261 | |
d77de738 ML |
1262 | |
1263 | ||
506f068e TB |
1264 | @node omp_get_num_teams |
1265 | @subsection @code{omp_get_num_teams} -- Number of teams | |
d77de738 ML |
1266 | @table @asis |
1267 | @item @emph{Description}: | |
506f068e | 1268 | Returns the number of teams in the current team region. |
d77de738 | 1269 | |
506f068e | 1270 | @item @emph{C/C++}: |
d77de738 | 1271 | @multitable @columnfractions .20 .80 |
506f068e | 1272 | @item @emph{Prototype}: @tab @code{int omp_get_num_teams(void);} |
d77de738 ML |
1273 | @end multitable |
1274 | ||
1275 | @item @emph{Fortran}: | |
1276 | @multitable @columnfractions .20 .80 | |
506f068e | 1277 | @item @emph{Interface}: @tab @code{integer function omp_get_num_teams()} |
d77de738 ML |
1278 | @end multitable |
1279 | ||
d77de738 | 1280 | @item @emph{Reference}: |
506f068e | 1281 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.32. |
d77de738 ML |
1282 | @end table |
1283 | ||
1284 | ||
1285 | ||
1286 | @node omp_get_team_num | |
506f068e | 1287 | @subsection @code{omp_get_team_num} -- Get team number |
d77de738 ML |
1288 | @table @asis |
1289 | @item @emph{Description}: | |
1290 | Returns the team number of the calling thread. | |
1291 | ||
1292 | @item @emph{C/C++}: | |
1293 | @multitable @columnfractions .20 .80 | |
1294 | @item @emph{Prototype}: @tab @code{int omp_get_team_num(void);} | |
1295 | @end multitable | |
1296 | ||
1297 | @item @emph{Fortran}: | |
1298 | @multitable @columnfractions .20 .80 | |
1299 | @item @emph{Interface}: @tab @code{integer function omp_get_team_num()} | |
1300 | @end multitable | |
1301 | ||
1302 | @item @emph{Reference}: | |
1303 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.33. | |
1304 | @end table | |
1305 | ||
1306 | ||
1307 | ||
506f068e TB |
1308 | @node omp_set_num_teams |
1309 | @subsection @code{omp_set_num_teams} -- Set upper teams limit for teams construct | |
d77de738 ML |
1310 | @table @asis |
1311 | @item @emph{Description}: | |
506f068e TB |
1312 | Specifies the upper bound for number of teams created by the teams construct |
1313 | which does not specify a @code{num_teams} clause. The | |
1314 | argument of @code{omp_set_num_teams} shall be a positive integer. | |
d77de738 ML |
1315 | |
1316 | @item @emph{C/C++}: | |
1317 | @multitable @columnfractions .20 .80 | |
506f068e | 1318 | @item @emph{Prototype}: @tab @code{void omp_set_num_teams(int num_teams);} |
d77de738 ML |
1319 | @end multitable |
1320 | ||
1321 | @item @emph{Fortran}: | |
1322 | @multitable @columnfractions .20 .80 | |
506f068e TB |
1323 | @item @emph{Interface}: @tab @code{subroutine omp_set_num_teams(num_teams)} |
1324 | @item @tab @code{integer, intent(in) :: num_teams} | |
d77de738 ML |
1325 | @end multitable |
1326 | ||
1327 | @item @emph{See also}: | |
506f068e | 1328 | @ref{OMP_NUM_TEAMS}, @ref{omp_get_num_teams}, @ref{omp_get_max_teams} |
d77de738 ML |
1329 | |
1330 | @item @emph{Reference}: | |
506f068e | 1331 | @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 3.4.3. |
d77de738 ML |
1332 | @end table |
1333 | ||
1334 | ||
1335 | ||
506f068e TB |
1336 | @node omp_get_max_teams |
1337 | @subsection @code{omp_get_max_teams} -- Maximum number of teams of teams region | |
d77de738 ML |
1338 | @table @asis |
1339 | @item @emph{Description}: | |
506f068e TB |
1340 | Return the maximum number of teams used for the teams region |
1341 | that does not use the clause @code{num_teams}. | |
d77de738 ML |
1342 | |
1343 | @item @emph{C/C++}: | |
1344 | @multitable @columnfractions .20 .80 | |
506f068e | 1345 | @item @emph{Prototype}: @tab @code{int omp_get_max_teams(void);} |
d77de738 ML |
1346 | @end multitable |
1347 | ||
1348 | @item @emph{Fortran}: | |
1349 | @multitable @columnfractions .20 .80 | |
506f068e | 1350 | @item @emph{Interface}: @tab @code{integer function omp_get_max_teams()} |
d77de738 ML |
1351 | @end multitable |
1352 | ||
1353 | @item @emph{See also}: | |
506f068e | 1354 | @ref{omp_set_num_teams}, @ref{omp_get_num_teams} |
d77de738 ML |
1355 | |
1356 | @item @emph{Reference}: | |
506f068e | 1357 | @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 3.4.4. |
d77de738 ML |
1358 | @end table |
1359 | ||
1360 | ||
1361 | ||
506f068e TB |
1362 | @node omp_set_teams_thread_limit |
1363 | @subsection @code{omp_set_teams_thread_limit} -- Set upper thread limit for teams construct | |
d77de738 ML |
1364 | @table @asis |
1365 | @item @emph{Description}: | |
15886c03 | 1366 | Specifies the upper bound for number of threads that are available |
506f068e TB |
1367 | for each team created by the teams construct which does not specify a |
1368 | @code{thread_limit} clause. The argument of | |
1369 | @code{omp_set_teams_thread_limit} shall be a positive integer. | |
d77de738 ML |
1370 | |
1371 | @item @emph{C/C++}: | |
1372 | @multitable @columnfractions .20 .80 | |
506f068e | 1373 | @item @emph{Prototype}: @tab @code{void omp_set_teams_thread_limit(int thread_limit);} |
d77de738 ML |
1374 | @end multitable |
1375 | ||
1376 | @item @emph{Fortran}: | |
1377 | @multitable @columnfractions .20 .80 | |
506f068e TB |
1378 | @item @emph{Interface}: @tab @code{subroutine omp_set_teams_thread_limit(thread_limit)} |
1379 | @item @tab @code{integer, intent(in) :: thread_limit} | |
d77de738 ML |
1380 | @end multitable |
1381 | ||
1382 | @item @emph{See also}: | |
506f068e | 1383 | @ref{OMP_TEAMS_THREAD_LIMIT}, @ref{omp_get_teams_thread_limit}, @ref{omp_get_thread_limit} |
d77de738 ML |
1384 | |
1385 | @item @emph{Reference}: | |
506f068e | 1386 | @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 3.4.5. |
d77de738 ML |
1387 | @end table |
1388 | ||
1389 | ||
1390 | ||
506f068e TB |
1391 | @node omp_get_thread_limit |
1392 | @subsection @code{omp_get_thread_limit} -- Maximum number of threads | |
d77de738 ML |
1393 | @table @asis |
1394 | @item @emph{Description}: | |
506f068e | 1395 | Return the maximum number of threads of the program. |
d77de738 ML |
1396 | |
1397 | @item @emph{C/C++}: | |
1398 | @multitable @columnfractions .20 .80 | |
506f068e | 1399 | @item @emph{Prototype}: @tab @code{int omp_get_thread_limit(void);} |
d77de738 ML |
1400 | @end multitable |
1401 | ||
1402 | @item @emph{Fortran}: | |
1403 | @multitable @columnfractions .20 .80 | |
506f068e | 1404 | @item @emph{Interface}: @tab @code{integer function omp_get_thread_limit()} |
d77de738 ML |
1405 | @end multitable |
1406 | ||
1407 | @item @emph{See also}: | |
506f068e | 1408 | @ref{omp_get_max_threads}, @ref{OMP_THREAD_LIMIT} |
d77de738 ML |
1409 | |
1410 | @item @emph{Reference}: | |
506f068e | 1411 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.14. |
d77de738 ML |
1412 | @end table |
1413 | ||
1414 | ||
1415 | ||
506f068e TB |
1416 | @node Tasking Routines |
1417 | @section Tasking Routines | |
1418 | ||
1419 | Routines relating to explicit tasks. | |
1420 | They have C linkage and do not throw exceptions. | |
1421 | ||
1422 | @menu | |
1423 | * omp_get_max_task_priority:: Maximum task priority value that can be set | |
819f3d36 | 1424 | * omp_in_explicit_task:: Whether a given task is an explicit task |
506f068e | 1425 | * omp_in_final:: Whether in final or included task region |
fcddf7ce TB |
1426 | @c * omp_is_free_agent:: <fixme>/TR12 |
1427 | @c * omp_ancestor_is_free_agent:: <fixme>/TR12 | |
506f068e TB |
1428 | @end menu |
1429 | ||
1430 | ||
1431 | ||
1432 | @node omp_get_max_task_priority | |
1433 | @subsection @code{omp_get_max_task_priority} -- Maximum priority value | |
1434 | that can be set for tasks. | |
d77de738 ML |
1435 | @table @asis |
1436 | @item @emph{Description}: | |
506f068e | 1437 | This function obtains the maximum allowed priority number for tasks. |
d77de738 | 1438 | |
506f068e | 1439 | @item @emph{C/C++} |
d77de738 | 1440 | @multitable @columnfractions .20 .80 |
506f068e | 1441 | @item @emph{Prototype}: @tab @code{int omp_get_max_task_priority(void);} |
d77de738 ML |
1442 | @end multitable |
1443 | ||
1444 | @item @emph{Fortran}: | |
1445 | @multitable @columnfractions .20 .80 | |
506f068e | 1446 | @item @emph{Interface}: @tab @code{integer function omp_get_max_task_priority()} |
d77de738 ML |
1447 | @end multitable |
1448 | ||
1449 | @item @emph{Reference}: | |
506f068e | 1450 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.29. |
d77de738 ML |
1451 | @end table |
1452 | ||
1453 | ||
506f068e | 1454 | |
819f3d36 TB |
1455 | @node omp_in_explicit_task |
1456 | @subsection @code{omp_in_explicit_task} -- Whether a given task is an explicit task | |
1457 | @table @asis | |
1458 | @item @emph{Description}: | |
1459 | The function returns the @var{explicit-task-var} ICV; it returns true when the | |
1460 | encountering task was generated by a task-generating construct such as | |
1461 | @code{target}, @code{task} or @code{taskloop}. Otherwise, the encountering task | |
1462 | is in an implicit task region such as generated by the implicit or explicit | |
1463 | @code{parallel} region and @code{omp_in_explicit_task} returns false. | |
1464 | ||
1465 | @item @emph{C/C++} | |
1466 | @multitable @columnfractions .20 .80 | |
1467 | @item @emph{Prototype}: @tab @code{int omp_in_explicit_task(void);} | |
1468 | @end multitable | |
1469 | ||
1470 | @item @emph{Fortran}: | |
1471 | @multitable @columnfractions .20 .80 | |
1472 | @item @emph{Interface}: @tab @code{logical function omp_in_explicit_task()} | |
1473 | @end multitable | |
1474 | ||
1475 | @item @emph{Reference}: | |
1476 | @uref{https://www.openmp.org, OpenMP specification v5.2}, Section 18.5.2. | |
1477 | @end table | |
1478 | ||
1479 | ||
1480 | ||
d77de738 | 1481 | @node omp_in_final |
506f068e | 1482 | @subsection @code{omp_in_final} -- Whether in final or included task region |
d77de738 ML |
1483 | @table @asis |
1484 | @item @emph{Description}: | |
1485 | This function returns @code{true} if currently running in a final | |
1486 | or included task region, @code{false} otherwise. Here, @code{true} | |
1487 | and @code{false} represent their language-specific counterparts. | |
1488 | ||
1489 | @item @emph{C/C++}: | |
1490 | @multitable @columnfractions .20 .80 | |
1491 | @item @emph{Prototype}: @tab @code{int omp_in_final(void);} | |
1492 | @end multitable | |
1493 | ||
1494 | @item @emph{Fortran}: | |
1495 | @multitable @columnfractions .20 .80 | |
1496 | @item @emph{Interface}: @tab @code{logical function omp_in_final()} | |
1497 | @end multitable | |
1498 | ||
1499 | @item @emph{Reference}: | |
1500 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.21. | |
1501 | @end table | |
1502 | ||
1503 | ||
1504 | ||
506f068e TB |
1505 | @c @node Resource Relinquishing Routines |
1506 | @c @section Resource Relinquishing Routines | |
1507 | @c | |
1508 | @c Routines releasing resources used by the OpenMP runtime. | |
1509 | @c They have C linkage and do not throw exceptions. | |
1510 | @c | |
1511 | @c @menu | |
1512 | @c * omp_pause_resource:: <fixme> | |
1513 | @c * omp_pause_resource_all:: <fixme> | |
1514 | @c @end menu | |
1515 | ||
1516 | @node Device Information Routines | |
1517 | @section Device Information Routines | |
1518 | ||
1519 | Routines related to devices available to an OpenMP program. | |
1520 | They have C linkage and do not throw exceptions. | |
1521 | ||
1522 | @menu | |
1523 | * omp_get_num_procs:: Number of processors online | |
1524 | @c * omp_get_max_progress_width:: <fixme>/TR11 | |
1525 | * omp_set_default_device:: Set the default device for target regions | |
1526 | * omp_get_default_device:: Get the default device for target regions | |
1527 | * omp_get_num_devices:: Number of target devices | |
1528 | * omp_get_device_num:: Get device that current thread is running on | |
1529 | * omp_is_initial_device:: Whether executing on the host device | |
1530 | * omp_get_initial_device:: Device number of host device | |
1531 | @end menu | |
1532 | ||
1533 | ||
1534 | ||
1535 | @node omp_get_num_procs | |
1536 | @subsection @code{omp_get_num_procs} -- Number of processors online | |
d77de738 ML |
1537 | @table @asis |
1538 | @item @emph{Description}: | |
506f068e | 1539 | Returns the number of processors online on that device. |
d77de738 ML |
1540 | |
1541 | @item @emph{C/C++}: | |
1542 | @multitable @columnfractions .20 .80 | |
506f068e | 1543 | @item @emph{Prototype}: @tab @code{int omp_get_num_procs(void);} |
d77de738 ML |
1544 | @end multitable |
1545 | ||
1546 | @item @emph{Fortran}: | |
1547 | @multitable @columnfractions .20 .80 | |
506f068e | 1548 | @item @emph{Interface}: @tab @code{integer function omp_get_num_procs()} |
d77de738 ML |
1549 | @end multitable |
1550 | ||
1551 | @item @emph{Reference}: | |
506f068e | 1552 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.5. |
d77de738 ML |
1553 | @end table |
1554 | ||
1555 | ||
1556 | ||
1557 | @node omp_set_default_device | |
506f068e | 1558 | @subsection @code{omp_set_default_device} -- Set the default device for target regions |
d77de738 ML |
1559 | @table @asis |
1560 | @item @emph{Description}: | |
1561 | Set the default device for target regions without device clause. The argument | |
1562 | shall be a nonnegative device number. | |
1563 | ||
1564 | @item @emph{C/C++}: | |
1565 | @multitable @columnfractions .20 .80 | |
1566 | @item @emph{Prototype}: @tab @code{void omp_set_default_device(int device_num);} | |
1567 | @end multitable | |
1568 | ||
1569 | @item @emph{Fortran}: | |
1570 | @multitable @columnfractions .20 .80 | |
1571 | @item @emph{Interface}: @tab @code{subroutine omp_set_default_device(device_num)} | |
1572 | @item @tab @code{integer device_num} | |
1573 | @end multitable | |
1574 | ||
1575 | @item @emph{See also}: | |
1576 | @ref{OMP_DEFAULT_DEVICE}, @ref{omp_get_default_device} | |
1577 | ||
1578 | @item @emph{Reference}: | |
1579 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.29. | |
1580 | @end table | |
1581 | ||
1582 | ||
1583 | ||
506f068e TB |
1584 | @node omp_get_default_device |
1585 | @subsection @code{omp_get_default_device} -- Get the default device for target regions | |
d77de738 ML |
1586 | @table @asis |
1587 | @item @emph{Description}: | |
506f068e | 1588 | Get the default device for target regions without device clause. |
2cd0689a | 1589 | |
d77de738 ML |
1590 | @item @emph{C/C++}: |
1591 | @multitable @columnfractions .20 .80 | |
506f068e | 1592 | @item @emph{Prototype}: @tab @code{int omp_get_default_device(void);} |
d77de738 ML |
1593 | @end multitable |
1594 | ||
1595 | @item @emph{Fortran}: | |
1596 | @multitable @columnfractions .20 .80 | |
506f068e | 1597 | @item @emph{Interface}: @tab @code{integer function omp_get_default_device()} |
d77de738 ML |
1598 | @end multitable |
1599 | ||
1600 | @item @emph{See also}: | |
506f068e | 1601 | @ref{OMP_DEFAULT_DEVICE}, @ref{omp_set_default_device} |
d77de738 ML |
1602 | |
1603 | @item @emph{Reference}: | |
506f068e | 1604 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.30. |
d77de738 ML |
1605 | @end table |
1606 | ||
1607 | ||
1608 | ||
506f068e TB |
1609 | @node omp_get_num_devices |
1610 | @subsection @code{omp_get_num_devices} -- Number of target devices | |
d77de738 ML |
1611 | @table @asis |
1612 | @item @emph{Description}: | |
506f068e | 1613 | Returns the number of target devices. |
d77de738 ML |
1614 | |
1615 | @item @emph{C/C++}: | |
1616 | @multitable @columnfractions .20 .80 | |
506f068e | 1617 | @item @emph{Prototype}: @tab @code{int omp_get_num_devices(void);} |
d77de738 ML |
1618 | @end multitable |
1619 | ||
1620 | @item @emph{Fortran}: | |
1621 | @multitable @columnfractions .20 .80 | |
506f068e | 1622 | @item @emph{Interface}: @tab @code{integer function omp_get_num_devices()} |
d77de738 ML |
1623 | @end multitable |
1624 | ||
d77de738 | 1625 | @item @emph{Reference}: |
506f068e | 1626 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.31. |
d77de738 ML |
1627 | @end table |
1628 | ||
1629 | ||
1630 | ||
506f068e TB |
1631 | @node omp_get_device_num |
1632 | @subsection @code{omp_get_device_num} -- Return device number of current device | |
d77de738 ML |
1633 | @table @asis |
1634 | @item @emph{Description}: | |
506f068e TB |
1635 | This function returns a device number that represents the device that the |
1636 | current thread is executing on. For OpenMP 5.0, this must be equal to the | |
1637 | value returned by the @code{omp_get_initial_device} function when called | |
1638 | from the host. | |
d77de738 | 1639 | |
506f068e | 1640 | @item @emph{C/C++} |
d77de738 | 1641 | @multitable @columnfractions .20 .80 |
506f068e | 1642 | @item @emph{Prototype}: @tab @code{int omp_get_device_num(void);} |
d77de738 ML |
1643 | @end multitable |
1644 | ||
1645 | @item @emph{Fortran}: | |
506f068e TB |
1646 | @multitable @columnfractions .20 .80 |
1647 | @item @emph{Interface}: @tab @code{integer function omp_get_device_num()} | |
d77de738 ML |
1648 | @end multitable |
1649 | ||
1650 | @item @emph{See also}: | |
506f068e | 1651 | @ref{omp_get_initial_device} |
d77de738 ML |
1652 | |
1653 | @item @emph{Reference}: | |
506f068e | 1654 | @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.2.37. |
d77de738 ML |
1655 | @end table |
1656 | ||
1657 | ||
1658 | ||
506f068e TB |
1659 | @node omp_is_initial_device |
1660 | @subsection @code{omp_is_initial_device} -- Whether executing on the host device | |
d77de738 ML |
1661 | @table @asis |
1662 | @item @emph{Description}: | |
506f068e TB |
1663 | This function returns @code{true} if currently running on the host device, |
1664 | @code{false} otherwise. Here, @code{true} and @code{false} represent | |
1665 | their language-specific counterparts. | |
d77de738 | 1666 | |
506f068e | 1667 | @item @emph{C/C++}: |
d77de738 | 1668 | @multitable @columnfractions .20 .80 |
506f068e | 1669 | @item @emph{Prototype}: @tab @code{int omp_is_initial_device(void);} |
d77de738 ML |
1670 | @end multitable |
1671 | ||
1672 | @item @emph{Fortran}: | |
1673 | @multitable @columnfractions .20 .80 | |
506f068e | 1674 | @item @emph{Interface}: @tab @code{logical function omp_is_initial_device()} |
d77de738 ML |
1675 | @end multitable |
1676 | ||
d77de738 | 1677 | @item @emph{Reference}: |
506f068e | 1678 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.34. |
d77de738 ML |
1679 | @end table |
1680 | ||
1681 | ||
1682 | ||
506f068e TB |
1683 | @node omp_get_initial_device |
1684 | @subsection @code{omp_get_initial_device} -- Return device number of initial device | |
d77de738 ML |
1685 | @table @asis |
1686 | @item @emph{Description}: | |
506f068e TB |
1687 | This function returns a device number that represents the host device. |
1688 | For OpenMP 5.1, this must be equal to the value returned by the | |
1689 | @code{omp_get_num_devices} function. | |
d77de738 | 1690 | |
506f068e | 1691 | @item @emph{C/C++} |
d77de738 | 1692 | @multitable @columnfractions .20 .80 |
506f068e | 1693 | @item @emph{Prototype}: @tab @code{int omp_get_initial_device(void);} |
d77de738 ML |
1694 | @end multitable |
1695 | ||
1696 | @item @emph{Fortran}: | |
1697 | @multitable @columnfractions .20 .80 | |
506f068e | 1698 | @item @emph{Interface}: @tab @code{integer function omp_get_initial_device()} |
d77de738 ML |
1699 | @end multitable |
1700 | ||
1701 | @item @emph{See also}: | |
506f068e | 1702 | @ref{omp_get_num_devices} |
d77de738 ML |
1703 | |
1704 | @item @emph{Reference}: | |
506f068e | 1705 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.35. |
d77de738 ML |
1706 | @end table |
1707 | ||
1708 | ||
1709 | ||
e0786ba6 TB |
1710 | @node Device Memory Routines |
1711 | @section Device Memory Routines | |
1712 | ||
1713 | Routines related to memory allocation and managing corresponding | |
1714 | pointers on devices. They have C linkage and do not throw exceptions. | |
1715 | ||
1716 | @menu | |
1717 | * omp_target_alloc:: Allocate device memory | |
1718 | * omp_target_free:: Free device memory | |
1719 | * omp_target_is_present:: Check whether storage is mapped | |
506f068e TB |
1720 | @c * omp_target_is_accessible:: <fixme> |
1721 | @c * omp_target_memcpy:: <fixme> | |
1722 | @c * omp_target_memcpy_rect:: <fixme> | |
1723 | @c * omp_target_memcpy_async:: <fixme> | |
1724 | @c * omp_target_memcpy_rect_async:: <fixme> | |
e0786ba6 TB |
1725 | @c * omp_target_memset:: <fixme>/TR12 |
1726 | @c * omp_target_memset_async:: <fixme>/TR12 | |
1727 | * omp_target_associate_ptr:: Associate a device pointer with a host pointer | |
1728 | * omp_target_disassociate_ptr:: Remove device--host pointer association | |
1729 | * omp_get_mapped_ptr:: Return device pointer to a host pointer | |
1730 | @end menu | |
1731 | ||
1732 | ||
1733 | ||
1734 | @node omp_target_alloc | |
1735 | @subsection @code{omp_target_alloc} -- Allocate device memory | |
1736 | @table @asis | |
1737 | @item @emph{Description}: | |
1738 | This routine allocates @var{size} bytes of memory in the device environment | |
1739 | associated with the device number @var{device_num}. If successful, a device | |
1740 | pointer is returned, otherwise a null pointer. | |
1741 | ||
1742 | In GCC, when the device is the host or the device shares memory with the host, | |
1743 | the memory is allocated on the host; in that case, when @var{size} is zero, | |
1744 | either NULL or a unique pointer value that can later be successfully passed to | |
1745 | @code{omp_target_free} is returned. When the allocation is not performed on | |
1746 | the host, a null pointer is returned when @var{size} is zero; in that case, | |
1747 | additionally a diagnostic might be printed to standard error (stderr). | |
1748 | ||
1749 | Running this routine in a @code{target} region except on the initial device | |
1750 | is not supported. | |
1751 | ||
1752 | @item @emph{C/C++} | |
1753 | @multitable @columnfractions .20 .80 | |
1754 | @item @emph{Prototype}: @tab @code{void *omp_target_alloc(size_t size, int device_num)} | |
1755 | @end multitable | |
1756 | ||
1757 | @item @emph{Fortran}: | |
1758 | @multitable @columnfractions .20 .80 | |
1759 | @item @emph{Interface}: @tab @code{type(c_ptr) function omp_target_alloc(size, device_num) bind(C)} | |
1760 | @item @tab @code{use, intrinsic :: iso_c_binding, only: c_ptr, c_int, c_size_t} | |
1761 | @item @tab @code{integer(c_size_t), value :: size} | |
1762 | @item @tab @code{integer(c_int), value :: device_num} | |
1763 | @end multitable | |
1764 | ||
1765 | @item @emph{See also}: | |
1766 | @ref{omp_target_free}, @ref{omp_target_associate_ptr} | |
1767 | ||
1768 | @item @emph{Reference}: | |
1769 | @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 18.8.1 | |
1770 | @end table | |
1771 | ||
1772 | ||
1773 | ||
1774 | @node omp_target_free | |
1775 | @subsection @code{omp_target_free} -- Free device memory | |
1776 | @table @asis | |
1777 | @item @emph{Description}: | |
1778 | This routine frees memory allocated by the @code{omp_target_alloc} routine. | |
1779 | The @var{device_ptr} argument must be either a null pointer or a device pointer | |
1780 | returned by @code{omp_target_alloc} for the specified @code{device_num}. The | |
1781 | device number @var{device_num} must be a conforming device number. | |
1782 | ||
1783 | Running this routine in a @code{target} region except on the initial device | |
1784 | is not supported. | |
1785 | ||
1786 | @item @emph{C/C++} | |
1787 | @multitable @columnfractions .20 .80 | |
1788 | @item @emph{Prototype}: @tab @code{void omp_target_free(void *device_ptr, int device_num)} | |
1789 | @end multitable | |
1790 | ||
1791 | @item @emph{Fortran}: | |
1792 | @multitable @columnfractions .20 .80 | |
1793 | @item @emph{Interface}: @tab @code{subroutine omp_target_free(device_ptr, device_num) bind(C)} | |
1794 | @item @tab @code{use, intrinsic :: iso_c_binding, only: c_ptr, c_int} | |
1795 | @item @tab @code{type(c_ptr), value :: device_ptr} | |
1796 | @item @tab @code{integer(c_int), value :: device_num} | |
1797 | @end multitable | |
1798 | ||
1799 | @item @emph{See also}: | |
1800 | @ref{omp_target_alloc}, @ref{omp_target_disassociate_ptr} | |
1801 | ||
1802 | @item @emph{Reference}: | |
1803 | @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 18.8.2 | |
1804 | @end table | |
1805 | ||
1806 | ||
1807 | ||
1808 | @node omp_target_is_present | |
1809 | @subsection @code{omp_target_is_present} -- Check whether storage is mapped | |
1810 | @table @asis | |
1811 | @item @emph{Description}: | |
1812 | This routine tests whether storage, identified by the host pointer @var{ptr} | |
1813 | is mapped to the device specified by @var{device_num}. If so, it returns | |
1814 | @emph{true} and otherwise @emph{false}. | |
1815 | ||
1816 | In GCC, this includes self mapping such that @code{omp_target_is_present} | |
1817 | returns @emph{true} when @var{device_num} specifies the host or when the host | |
1818 | and the device share memory. If @var{ptr} is a null pointer, @var{true} is | |
1819 | returned and if @var{device_num} is an invalid device number, @var{false} is | |
1820 | returned. | |
1821 | ||
1822 | If those conditions do not apply, @emph{true} is returned if the association has | |
1823 | been established by an explicit or implicit @code{map} clause, the | |
1824 | @code{declare target} directive or a call to the @code{omp_target_associate_ptr} | |
1825 | routine. | |
1826 | ||
1827 | Running this routine in a @code{target} region except on the initial device | |
1828 | is not supported. | |
1829 | ||
1830 | @item @emph{C/C++} | |
1831 | @multitable @columnfractions .20 .80 | |
1832 | @item @emph{Prototype}: @tab @code{int omp_target_is_present(const void *ptr,} | |
1833 | @item @tab @code{ int device_num)} | |
1834 | @end multitable | |
1835 | ||
1836 | @item @emph{Fortran}: | |
1837 | @multitable @columnfractions .20 .80 | |
1838 | @item @emph{Interface}: @tab @code{integer(c_int) function omp_target_is_present(ptr, &} | |
1839 | @item @tab @code{ device_num) bind(C)} | |
1840 | @item @tab @code{use, intrinsic :: iso_c_binding, only: c_ptr, c_int} | |
1841 | @item @tab @code{type(c_ptr), value :: ptr} | |
1842 | @item @tab @code{integer(c_int), value :: device_num} | |
1843 | @end multitable | |
1844 | ||
1845 | @item @emph{See also}: | |
1846 | @ref{omp_target_associate_ptr} | |
1847 | ||
1848 | @item @emph{Reference}: | |
1849 | @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 18.8.3 | |
1850 | @end table | |
1851 | ||
1852 | ||
1853 | ||
1854 | @node omp_target_associate_ptr | |
1855 | @subsection @code{omp_target_associate_ptr} -- Associate a device pointer with a host pointer | |
1856 | @table @asis | |
1857 | @item @emph{Description}: | |
1858 | This routine associates storage on the host with storage on a device identified | |
1859 | by @var{device_num}. The device pointer is usually obtained by calling | |
1860 | @code{omp_target_alloc} or by other means (but not by using the @code{map} | |
1861 | clauses or the @code{declare target} directive). The host pointer should point | |
1862 | to memory that has a storage size of at least @var{size}. | |
1863 | ||
1864 | The @var{device_offset} parameter specifies the offset into @var{device_ptr} | |
1865 | that is used as the base address for the device side of the mapping; the | |
1866 | storage size should be at least @var{device_offset} plus @var{size}. | |
1867 | ||
1868 | After the association, the host pointer can be used in a @code{map} clause and | |
1869 | in the @code{to} and @code{from} clauses of the @code{target update} directive | |
1870 | to transfer data between the associated pointers. The reference count of such | |
1871 | associated storage is infinite. The association can be removed by calling | |
1872 | @code{omp_target_disassociate_ptr} which should be done before the lifetime | |
1873 | of either either storage ends. | |
1874 | ||
1875 | The routine returns nonzero (@code{EINVAL}) when the @var{device_num} invalid, | |
1876 | for when the initial device or the associated device shares memory with the | |
1877 | host. @code{omp_target_associate_ptr} returns zero if @var{host_ptr} points | |
1878 | into already associated storage that is fully inside of a previously associated | |
1879 | memory. Otherwise, if the association was successful zero is returned; if none | |
1880 | of the cases above apply, nonzero (@code{EINVAL}) is returned. | |
1881 | ||
1882 | The @code{omp_target_is_present} routine can be used to test whether | |
1883 | associated storage for a device pointer exists. | |
1884 | ||
1885 | Running this routine in a @code{target} region except on the initial device | |
1886 | is not supported. | |
1887 | ||
1888 | @item @emph{C/C++} | |
1889 | @multitable @columnfractions .20 .80 | |
1890 | @item @emph{Prototype}: @tab @code{int omp_target_associate_ptr(const void *host_ptr,} | |
1891 | @item @tab @code{ const void *device_ptr,} | |
1892 | @item @tab @code{ size_t size,} | |
1893 | @item @tab @code{ size_t device_offset,} | |
1894 | @item @tab @code{ int device_num)} | |
1895 | @end multitable | |
1896 | ||
1897 | @item @emph{Fortran}: | |
1898 | @multitable @columnfractions .20 .80 | |
1899 | @item @emph{Interface}: @tab @code{integer(c_int) function omp_target_associate_ptr(host_ptr, &} | |
1900 | @item @tab @code{ device_ptr, size, device_offset, device_num) bind(C)} | |
1901 | @item @tab @code{use, intrinsic :: iso_c_binding, only: c_ptr, c_int, c_size_t} | |
1902 | @item @tab @code{type(c_ptr), value :: host_ptr, device_ptr} | |
1903 | @item @tab @code{integer(c_size_t), value :: size, device_offset} | |
1904 | @item @tab @code{integer(c_int), value :: device_num} | |
1905 | @end multitable | |
1906 | ||
1907 | @item @emph{See also}: | |
1908 | @ref{omp_target_disassociate_ptr}, @ref{omp_target_is_present}, | |
1909 | @ref{omp_target_alloc} | |
1910 | ||
1911 | @item @emph{Reference}: | |
1912 | @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 18.8.9 | |
1913 | @end table | |
1914 | ||
1915 | ||
1916 | ||
1917 | @node omp_target_disassociate_ptr | |
1918 | @subsection @code{omp_target_disassociate_ptr} -- Remove device--host pointer association | |
1919 | @table @asis | |
1920 | @item @emph{Description}: | |
1921 | This routine removes the storage association established by calling | |
1922 | @code{omp_target_associate_ptr} and sets the reference count to zero, | |
1923 | even if @code{omp_target_associate_ptr} was invoked multiple times for | |
1924 | for host pointer @code{ptr}. If applicable, the device memory needs | |
1925 | to be freed by the user. | |
1926 | ||
1927 | If an associated device storage location for the @var{device_num} was | |
1928 | found and has infinite reference count, the association is removed and | |
1929 | zero is returned. In all other cases, nonzero (@code{EINVAL}) is returned | |
1930 | and no other action is taken. | |
1931 | ||
1932 | Note that passing a host pointer where the association to the device pointer | |
1933 | was established with the @code{declare target} directive yields undefined | |
1934 | behavior. | |
1935 | ||
1936 | Running this routine in a @code{target} region except on the initial device | |
1937 | is not supported. | |
1938 | ||
1939 | @item @emph{C/C++} | |
1940 | @multitable @columnfractions .20 .80 | |
1941 | @item @emph{Prototype}: @tab @code{int omp_target_disassociate_ptr(const void *ptr,} | |
1942 | @item @tab @code{ int device_num)} | |
1943 | @end multitable | |
1944 | ||
1945 | @item @emph{Fortran}: | |
1946 | @multitable @columnfractions .20 .80 | |
1947 | @item @emph{Interface}: @tab @code{integer(c_int) function omp_target_disassociate_ptr(ptr, &} | |
1948 | @item @tab @code{ device_num) bind(C)} | |
1949 | @item @tab @code{use, intrinsic :: iso_c_binding, only: c_ptr, c_int} | |
1950 | @item @tab @code{type(c_ptr), value :: ptr} | |
1951 | @item @tab @code{integer(c_int), value :: device_num} | |
1952 | @end multitable | |
1953 | ||
1954 | @item @emph{See also}: | |
1955 | @ref{omp_target_associate_ptr} | |
1956 | ||
1957 | @item @emph{Reference}: | |
1958 | @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 18.8.10 | |
1959 | @end table | |
1960 | ||
1961 | ||
1962 | ||
1963 | @node omp_get_mapped_ptr | |
1964 | @subsection @code{omp_get_mapped_ptr} -- Return device pointer to a host pointer | |
1965 | @table @asis | |
1966 | @item @emph{Description}: | |
1967 | If the device number is refers to the initial device or to a device with | |
1968 | memory accessible from the host (shared memory), the @code{omp_get_mapped_ptr} | |
bc238c40 | 1969 | routines returns the value of the passed @var{ptr}. Otherwise, if associated |
e0786ba6 TB |
1970 | storage to the passed host pointer @var{ptr} exists on device associated with |
1971 | @var{device_num}, it returns that pointer. In all other cases and in cases of | |
1972 | an error, a null pointer is returned. | |
1973 | ||
1974 | The association of storage location is established either via an explicit or | |
1975 | implicit @code{map} clause, the @code{declare target} directive or the | |
1976 | @code{omp_target_associate_ptr} routine. | |
1977 | ||
1978 | Running this routine in a @code{target} region except on the initial device | |
1979 | is not supported. | |
1980 | ||
1981 | @item @emph{C/C++} | |
1982 | @multitable @columnfractions .20 .80 | |
1983 | @item @emph{Prototype}: @tab @code{void *omp_get_mapped_ptr(const void *ptr, int device_num);} | |
1984 | @end multitable | |
1985 | ||
1986 | @item @emph{Fortran}: | |
1987 | @multitable @columnfractions .20 .80 | |
1988 | @item @emph{Interface}: @tab @code{type(c_ptr) function omp_get_mapped_ptr(ptr, device_num) bind(C)} | |
1989 | @item @tab @code{use, intrinsic :: iso_c_binding, only: c_ptr, c_int} | |
1990 | @item @tab @code{type(c_ptr), value :: ptr} | |
1991 | @item @tab @code{integer(c_int), value :: device_num} | |
1992 | @end multitable | |
1993 | ||
1994 | @item @emph{See also}: | |
1995 | @ref{omp_target_associate_ptr} | |
1996 | ||
1997 | @item @emph{Reference}: | |
1998 | @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 18.8.11 | |
1999 | @end table | |
2000 | ||
2001 | ||
506f068e TB |
2002 | |
2003 | @node Lock Routines | |
2004 | @section Lock Routines | |
2005 | ||
2006 | Initialize, set, test, unset and destroy simple and nested locks. | |
2007 | The routines have C linkage and do not throw exceptions. | |
2008 | ||
2009 | @menu | |
2010 | * omp_init_lock:: Initialize simple lock | |
2011 | * omp_init_nest_lock:: Initialize nested lock | |
2012 | @c * omp_init_lock_with_hint:: <fixme> | |
2013 | @c * omp_init_nest_lock_with_hint:: <fixme> | |
2014 | * omp_destroy_lock:: Destroy simple lock | |
2015 | * omp_destroy_nest_lock:: Destroy nested lock | |
2016 | * omp_set_lock:: Wait for and set simple lock | |
2017 | * omp_set_nest_lock:: Wait for and set simple lock | |
2018 | * omp_unset_lock:: Unset simple lock | |
2019 | * omp_unset_nest_lock:: Unset nested lock | |
2020 | * omp_test_lock:: Test and set simple lock if available | |
2021 | * omp_test_nest_lock:: Test and set nested lock if available | |
2022 | @end menu | |
2023 | ||
2024 | ||
2025 | ||
d77de738 | 2026 | @node omp_init_lock |
506f068e | 2027 | @subsection @code{omp_init_lock} -- Initialize simple lock |
d77de738 ML |
2028 | @table @asis |
2029 | @item @emph{Description}: | |
2030 | Initialize a simple lock. After initialization, the lock is in | |
2031 | an unlocked state. | |
2032 | ||
2033 | @item @emph{C/C++}: | |
2034 | @multitable @columnfractions .20 .80 | |
2035 | @item @emph{Prototype}: @tab @code{void omp_init_lock(omp_lock_t *lock);} | |
2036 | @end multitable | |
2037 | ||
2038 | @item @emph{Fortran}: | |
2039 | @multitable @columnfractions .20 .80 | |
2040 | @item @emph{Interface}: @tab @code{subroutine omp_init_lock(svar)} | |
2041 | @item @tab @code{integer(omp_lock_kind), intent(out) :: svar} | |
2042 | @end multitable | |
2043 | ||
2044 | @item @emph{See also}: | |
2045 | @ref{omp_destroy_lock} | |
2046 | ||
2047 | @item @emph{Reference}: | |
2048 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.1. | |
2049 | @end table | |
2050 | ||
2051 | ||
2052 | ||
506f068e TB |
2053 | @node omp_init_nest_lock |
2054 | @subsection @code{omp_init_nest_lock} -- Initialize nested lock | |
d77de738 ML |
2055 | @table @asis |
2056 | @item @emph{Description}: | |
506f068e TB |
2057 | Initialize a nested lock. After initialization, the lock is in |
2058 | an unlocked state and the nesting count is set to zero. | |
d77de738 ML |
2059 | |
2060 | @item @emph{C/C++}: | |
2061 | @multitable @columnfractions .20 .80 | |
506f068e | 2062 | @item @emph{Prototype}: @tab @code{void omp_init_nest_lock(omp_nest_lock_t *lock);} |
d77de738 ML |
2063 | @end multitable |
2064 | ||
2065 | @item @emph{Fortran}: | |
2066 | @multitable @columnfractions .20 .80 | |
506f068e TB |
2067 | @item @emph{Interface}: @tab @code{subroutine omp_init_nest_lock(nvar)} |
2068 | @item @tab @code{integer(omp_nest_lock_kind), intent(out) :: nvar} | |
d77de738 ML |
2069 | @end multitable |
2070 | ||
2071 | @item @emph{See also}: | |
506f068e | 2072 | @ref{omp_destroy_nest_lock} |
d77de738 | 2073 | |
506f068e TB |
2074 | @item @emph{Reference}: |
2075 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.1. | |
d77de738 ML |
2076 | @end table |
2077 | ||
2078 | ||
2079 | ||
506f068e TB |
2080 | @node omp_destroy_lock |
2081 | @subsection @code{omp_destroy_lock} -- Destroy simple lock | |
d77de738 ML |
2082 | @table @asis |
2083 | @item @emph{Description}: | |
506f068e TB |
2084 | Destroy a simple lock. In order to be destroyed, a simple lock must be |
2085 | in the unlocked state. | |
d77de738 ML |
2086 | |
2087 | @item @emph{C/C++}: | |
2088 | @multitable @columnfractions .20 .80 | |
506f068e | 2089 | @item @emph{Prototype}: @tab @code{void omp_destroy_lock(omp_lock_t *lock);} |
d77de738 ML |
2090 | @end multitable |
2091 | ||
2092 | @item @emph{Fortran}: | |
2093 | @multitable @columnfractions .20 .80 | |
506f068e | 2094 | @item @emph{Interface}: @tab @code{subroutine omp_destroy_lock(svar)} |
d77de738 ML |
2095 | @item @tab @code{integer(omp_lock_kind), intent(inout) :: svar} |
2096 | @end multitable | |
2097 | ||
2098 | @item @emph{See also}: | |
506f068e | 2099 | @ref{omp_init_lock} |
d77de738 ML |
2100 | |
2101 | @item @emph{Reference}: | |
506f068e | 2102 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.3. |
d77de738 ML |
2103 | @end table |
2104 | ||
2105 | ||
2106 | ||
506f068e TB |
2107 | @node omp_destroy_nest_lock |
2108 | @subsection @code{omp_destroy_nest_lock} -- Destroy nested lock | |
d77de738 ML |
2109 | @table @asis |
2110 | @item @emph{Description}: | |
506f068e TB |
2111 | Destroy a nested lock. In order to be destroyed, a nested lock must be |
2112 | in the unlocked state and its nesting count must equal zero. | |
d77de738 ML |
2113 | |
2114 | @item @emph{C/C++}: | |
2115 | @multitable @columnfractions .20 .80 | |
506f068e | 2116 | @item @emph{Prototype}: @tab @code{void omp_destroy_nest_lock(omp_nest_lock_t *);} |
d77de738 ML |
2117 | @end multitable |
2118 | ||
2119 | @item @emph{Fortran}: | |
2120 | @multitable @columnfractions .20 .80 | |
506f068e TB |
2121 | @item @emph{Interface}: @tab @code{subroutine omp_destroy_nest_lock(nvar)} |
2122 | @item @tab @code{integer(omp_nest_lock_kind), intent(inout) :: nvar} | |
d77de738 ML |
2123 | @end multitable |
2124 | ||
2125 | @item @emph{See also}: | |
506f068e | 2126 | @ref{omp_init_lock} |
d77de738 ML |
2127 | |
2128 | @item @emph{Reference}: | |
506f068e | 2129 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.3. |
d77de738 ML |
2130 | @end table |
2131 | ||
2132 | ||
2133 | ||
506f068e TB |
2134 | @node omp_set_lock |
2135 | @subsection @code{omp_set_lock} -- Wait for and set simple lock | |
d77de738 ML |
2136 | @table @asis |
2137 | @item @emph{Description}: | |
506f068e TB |
2138 | Before setting a simple lock, the lock variable must be initialized by |
2139 | @code{omp_init_lock}. The calling thread is blocked until the lock | |
2140 | is available. If the lock is already held by the current thread, | |
2141 | a deadlock occurs. | |
d77de738 ML |
2142 | |
2143 | @item @emph{C/C++}: | |
2144 | @multitable @columnfractions .20 .80 | |
506f068e | 2145 | @item @emph{Prototype}: @tab @code{void omp_set_lock(omp_lock_t *lock);} |
d77de738 ML |
2146 | @end multitable |
2147 | ||
2148 | @item @emph{Fortran}: | |
2149 | @multitable @columnfractions .20 .80 | |
506f068e | 2150 | @item @emph{Interface}: @tab @code{subroutine omp_set_lock(svar)} |
d77de738 ML |
2151 | @item @tab @code{integer(omp_lock_kind), intent(inout) :: svar} |
2152 | @end multitable | |
2153 | ||
2154 | @item @emph{See also}: | |
506f068e | 2155 | @ref{omp_init_lock}, @ref{omp_test_lock}, @ref{omp_unset_lock} |
d77de738 ML |
2156 | |
2157 | @item @emph{Reference}: | |
506f068e | 2158 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.4. |
d77de738 ML |
2159 | @end table |
2160 | ||
2161 | ||
2162 | ||
d77de738 | 2163 | @node omp_set_nest_lock |
506f068e | 2164 | @subsection @code{omp_set_nest_lock} -- Wait for and set nested lock |
d77de738 ML |
2165 | @table @asis |
2166 | @item @emph{Description}: | |
2167 | Before setting a nested lock, the lock variable must be initialized by | |
2168 | @code{omp_init_nest_lock}. The calling thread is blocked until the lock | |
2169 | is available. If the lock is already held by the current thread, the | |
2170 | nesting count for the lock is incremented. | |
2171 | ||
2172 | @item @emph{C/C++}: | |
2173 | @multitable @columnfractions .20 .80 | |
2174 | @item @emph{Prototype}: @tab @code{void omp_set_nest_lock(omp_nest_lock_t *lock);} | |
2175 | @end multitable | |
2176 | ||
2177 | @item @emph{Fortran}: | |
2178 | @multitable @columnfractions .20 .80 | |
2179 | @item @emph{Interface}: @tab @code{subroutine omp_set_nest_lock(nvar)} | |
2180 | @item @tab @code{integer(omp_nest_lock_kind), intent(inout) :: nvar} | |
2181 | @end multitable | |
2182 | ||
2183 | @item @emph{See also}: | |
2184 | @ref{omp_init_nest_lock}, @ref{omp_unset_nest_lock} | |
2185 | ||
2186 | @item @emph{Reference}: | |
2187 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.4. | |
2188 | @end table | |
2189 | ||
2190 | ||
2191 | ||
506f068e TB |
2192 | @node omp_unset_lock |
2193 | @subsection @code{omp_unset_lock} -- Unset simple lock | |
d77de738 ML |
2194 | @table @asis |
2195 | @item @emph{Description}: | |
506f068e TB |
2196 | A simple lock about to be unset must have been locked by @code{omp_set_lock} |
2197 | or @code{omp_test_lock} before. In addition, the lock must be held by the | |
2198 | thread calling @code{omp_unset_lock}. Then, the lock becomes unlocked. If one | |
2199 | or more threads attempted to set the lock before, one of them is chosen to, | |
2200 | again, set the lock to itself. | |
d77de738 ML |
2201 | |
2202 | @item @emph{C/C++}: | |
2203 | @multitable @columnfractions .20 .80 | |
506f068e | 2204 | @item @emph{Prototype}: @tab @code{void omp_unset_lock(omp_lock_t *lock);} |
d77de738 ML |
2205 | @end multitable |
2206 | ||
2207 | @item @emph{Fortran}: | |
2208 | @multitable @columnfractions .20 .80 | |
506f068e TB |
2209 | @item @emph{Interface}: @tab @code{subroutine omp_unset_lock(svar)} |
2210 | @item @tab @code{integer(omp_lock_kind), intent(inout) :: svar} | |
d77de738 ML |
2211 | @end multitable |
2212 | ||
d77de738 | 2213 | @item @emph{See also}: |
506f068e | 2214 | @ref{omp_set_lock}, @ref{omp_test_lock} |
d77de738 ML |
2215 | |
2216 | @item @emph{Reference}: | |
506f068e | 2217 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.5. |
d77de738 ML |
2218 | @end table |
2219 | ||
2220 | ||
2221 | ||
2222 | @node omp_unset_nest_lock | |
506f068e | 2223 | @subsection @code{omp_unset_nest_lock} -- Unset nested lock |
d77de738 ML |
2224 | @table @asis |
2225 | @item @emph{Description}: | |
2226 | A nested lock about to be unset must have been locked by @code{omp_set_nested_lock} | |
2227 | or @code{omp_test_nested_lock} before. In addition, the lock must be held by the | |
2228 | thread calling @code{omp_unset_nested_lock}. If the nesting count drops to zero, the | |
2229 | lock becomes unlocked. If one ore more threads attempted to set the lock before, | |
2230 | one of them is chosen to, again, set the lock to itself. | |
2231 | ||
2232 | @item @emph{C/C++}: | |
2233 | @multitable @columnfractions .20 .80 | |
2234 | @item @emph{Prototype}: @tab @code{void omp_unset_nest_lock(omp_nest_lock_t *lock);} | |
2235 | @end multitable | |
2236 | ||
2237 | @item @emph{Fortran}: | |
2238 | @multitable @columnfractions .20 .80 | |
2239 | @item @emph{Interface}: @tab @code{subroutine omp_unset_nest_lock(nvar)} | |
2240 | @item @tab @code{integer(omp_nest_lock_kind), intent(inout) :: nvar} | |
2241 | @end multitable | |
2242 | ||
2243 | @item @emph{See also}: | |
2244 | @ref{omp_set_nest_lock} | |
2245 | ||
2246 | @item @emph{Reference}: | |
2247 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.5. | |
2248 | @end table | |
2249 | ||
2250 | ||
2251 | ||
506f068e TB |
2252 | @node omp_test_lock |
2253 | @subsection @code{omp_test_lock} -- Test and set simple lock if available | |
d77de738 ML |
2254 | @table @asis |
2255 | @item @emph{Description}: | |
506f068e TB |
2256 | Before setting a simple lock, the lock variable must be initialized by |
2257 | @code{omp_init_lock}. Contrary to @code{omp_set_lock}, @code{omp_test_lock} | |
2258 | does not block if the lock is not available. This function returns | |
2259 | @code{true} upon success, @code{false} otherwise. Here, @code{true} and | |
2260 | @code{false} represent their language-specific counterparts. | |
d77de738 ML |
2261 | |
2262 | @item @emph{C/C++}: | |
2263 | @multitable @columnfractions .20 .80 | |
506f068e | 2264 | @item @emph{Prototype}: @tab @code{int omp_test_lock(omp_lock_t *lock);} |
d77de738 ML |
2265 | @end multitable |
2266 | ||
2267 | @item @emph{Fortran}: | |
2268 | @multitable @columnfractions .20 .80 | |
506f068e TB |
2269 | @item @emph{Interface}: @tab @code{logical function omp_test_lock(svar)} |
2270 | @item @tab @code{integer(omp_lock_kind), intent(inout) :: svar} | |
2271 | @end multitable | |
2272 | ||
2273 | @item @emph{See also}: | |
2274 | @ref{omp_init_lock}, @ref{omp_set_lock}, @ref{omp_set_lock} | |
2275 | ||
2276 | @item @emph{Reference}: | |
2277 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.6. | |
2278 | @end table | |
2279 | ||
2280 | ||
2281 | ||
2282 | @node omp_test_nest_lock | |
2283 | @subsection @code{omp_test_nest_lock} -- Test and set nested lock if available | |
2284 | @table @asis | |
2285 | @item @emph{Description}: | |
2286 | Before setting a nested lock, the lock variable must be initialized by | |
2287 | @code{omp_init_nest_lock}. Contrary to @code{omp_set_nest_lock}, | |
2288 | @code{omp_test_nest_lock} does not block if the lock is not available. | |
2289 | If the lock is already held by the current thread, the new nesting count | |
2290 | is returned. Otherwise, the return value equals zero. | |
2291 | ||
2292 | @item @emph{C/C++}: | |
2293 | @multitable @columnfractions .20 .80 | |
2294 | @item @emph{Prototype}: @tab @code{int omp_test_nest_lock(omp_nest_lock_t *lock);} | |
2295 | @end multitable | |
2296 | ||
2297 | @item @emph{Fortran}: | |
2298 | @multitable @columnfractions .20 .80 | |
2299 | @item @emph{Interface}: @tab @code{logical function omp_test_nest_lock(nvar)} | |
d77de738 ML |
2300 | @item @tab @code{integer(omp_nest_lock_kind), intent(inout) :: nvar} |
2301 | @end multitable | |
2302 | ||
506f068e | 2303 | |
d77de738 | 2304 | @item @emph{See also}: |
506f068e | 2305 | @ref{omp_init_lock}, @ref{omp_set_lock}, @ref{omp_set_lock} |
d77de738 ML |
2306 | |
2307 | @item @emph{Reference}: | |
506f068e | 2308 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.3.6. |
d77de738 ML |
2309 | @end table |
2310 | ||
2311 | ||
2312 | ||
506f068e TB |
2313 | @node Timing Routines |
2314 | @section Timing Routines | |
2315 | ||
2316 | Portable, thread-based, wall clock timer. | |
2317 | The routines have C linkage and do not throw exceptions. | |
2318 | ||
2319 | @menu | |
2320 | * omp_get_wtick:: Get timer precision. | |
2321 | * omp_get_wtime:: Elapsed wall clock time. | |
2322 | @end menu | |
2323 | ||
2324 | ||
2325 | ||
d77de738 | 2326 | @node omp_get_wtick |
506f068e | 2327 | @subsection @code{omp_get_wtick} -- Get timer precision |
d77de738 ML |
2328 | @table @asis |
2329 | @item @emph{Description}: | |
2330 | Gets the timer precision, i.e., the number of seconds between two | |
2331 | successive clock ticks. | |
2332 | ||
2333 | @item @emph{C/C++}: | |
2334 | @multitable @columnfractions .20 .80 | |
2335 | @item @emph{Prototype}: @tab @code{double omp_get_wtick(void);} | |
2336 | @end multitable | |
2337 | ||
2338 | @item @emph{Fortran}: | |
2339 | @multitable @columnfractions .20 .80 | |
2340 | @item @emph{Interface}: @tab @code{double precision function omp_get_wtick()} | |
2341 | @end multitable | |
2342 | ||
2343 | @item @emph{See also}: | |
2344 | @ref{omp_get_wtime} | |
2345 | ||
2346 | @item @emph{Reference}: | |
2347 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.4.2. | |
2348 | @end table | |
2349 | ||
2350 | ||
2351 | ||
2352 | @node omp_get_wtime | |
506f068e | 2353 | @subsection @code{omp_get_wtime} -- Elapsed wall clock time |
d77de738 ML |
2354 | @table @asis |
2355 | @item @emph{Description}: | |
2356 | Elapsed wall clock time in seconds. The time is measured per thread, no | |
2357 | guarantee can be made that two distinct threads measure the same time. | |
2358 | Time is measured from some "time in the past", which is an arbitrary time | |
2359 | guaranteed not to change during the execution of the program. | |
2360 | ||
2361 | @item @emph{C/C++}: | |
2362 | @multitable @columnfractions .20 .80 | |
2363 | @item @emph{Prototype}: @tab @code{double omp_get_wtime(void);} | |
2364 | @end multitable | |
2365 | ||
2366 | @item @emph{Fortran}: | |
2367 | @multitable @columnfractions .20 .80 | |
2368 | @item @emph{Interface}: @tab @code{double precision function omp_get_wtime()} | |
2369 | @end multitable | |
2370 | ||
2371 | @item @emph{See also}: | |
2372 | @ref{omp_get_wtick} | |
2373 | ||
2374 | @item @emph{Reference}: | |
2375 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.4.1. | |
2376 | @end table | |
2377 | ||
2378 | ||
2379 | ||
506f068e TB |
2380 | @node Event Routine |
2381 | @section Event Routine | |
2382 | ||
2383 | Support for event objects. | |
2384 | The routine has C linkage and do not throw exceptions. | |
2385 | ||
2386 | @menu | |
2387 | * omp_fulfill_event:: Fulfill and destroy an OpenMP event. | |
2388 | @end menu | |
2389 | ||
2390 | ||
2391 | ||
d77de738 | 2392 | @node omp_fulfill_event |
506f068e | 2393 | @subsection @code{omp_fulfill_event} -- Fulfill and destroy an OpenMP event |
d77de738 ML |
2394 | @table @asis |
2395 | @item @emph{Description}: | |
2396 | Fulfill the event associated with the event handle argument. Currently, it | |
2397 | is only used to fulfill events generated by detach clauses on task | |
2398 | constructs - the effect of fulfilling the event is to allow the task to | |
2399 | complete. | |
2400 | ||
2401 | The result of calling @code{omp_fulfill_event} with an event handle other | |
2402 | than that generated by a detach clause is undefined. Calling it with an | |
2403 | event handle that has already been fulfilled is also undefined. | |
2404 | ||
2405 | @item @emph{C/C++}: | |
2406 | @multitable @columnfractions .20 .80 | |
2407 | @item @emph{Prototype}: @tab @code{void omp_fulfill_event(omp_event_handle_t event);} | |
2408 | @end multitable | |
2409 | ||
2410 | @item @emph{Fortran}: | |
2411 | @multitable @columnfractions .20 .80 | |
2412 | @item @emph{Interface}: @tab @code{subroutine omp_fulfill_event(event)} | |
2413 | @item @tab @code{integer (kind=omp_event_handle_kind) :: event} | |
2414 | @end multitable | |
2415 | ||
2416 | @item @emph{Reference}: | |
2417 | @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.5.1. | |
2418 | @end table | |
2419 | ||
2420 | ||
2421 | ||
506f068e TB |
2422 | @c @node Interoperability Routines |
2423 | @c @section Interoperability Routines | |
2424 | @c | |
2425 | @c Routines to obtain properties from an @code{omp_interop_t} object. | |
2426 | @c They have C linkage and do not throw exceptions. | |
2427 | @c | |
2428 | @c @menu | |
2429 | @c * omp_get_num_interop_properties:: <fixme> | |
2430 | @c * omp_get_interop_int:: <fixme> | |
2431 | @c * omp_get_interop_ptr:: <fixme> | |
2432 | @c * omp_get_interop_str:: <fixme> | |
2433 | @c * omp_get_interop_name:: <fixme> | |
2434 | @c * omp_get_interop_type_desc:: <fixme> | |
2435 | @c * omp_get_interop_rc_desc:: <fixme> | |
2436 | @c @end menu | |
2437 | ||
971f119f TB |
2438 | @node Memory Management Routines |
2439 | @section Memory Management Routines | |
2440 | ||
2441 | Routines to manage and allocate memory on the current device. | |
2442 | They have C linkage and do not throw exceptions. | |
2443 | ||
2444 | @menu | |
2445 | * omp_init_allocator:: Create an allocator | |
2446 | * omp_destroy_allocator:: Destroy an allocator | |
2447 | * omp_set_default_allocator:: Set the default allocator | |
2448 | * omp_get_default_allocator:: Get the default allocator | |
bc238c40 TB |
2449 | * omp_alloc:: Memory allocation with an allocator |
2450 | * omp_aligned_alloc:: Memory allocation with an allocator and alignment | |
2451 | * omp_free:: Freeing memory allocated with OpenMP routines | |
2452 | * omp_calloc:: Allocate nullified memory with an allocator | |
2453 | * omp_aligned_calloc:: Allocate nullified aligned memory with an allocator | |
2454 | * omp_realloc:: Reallocate memory allocated with OpenMP routines | |
506f068e TB |
2455 | @c * omp_get_memspace_num_resources:: <fixme>/TR11 |
2456 | @c * omp_get_submemspace:: <fixme>/TR11 | |
971f119f TB |
2457 | @end menu |
2458 | ||
2459 | ||
2460 | ||
2461 | @node omp_init_allocator | |
2462 | @subsection @code{omp_init_allocator} -- Create an allocator | |
2463 | @table @asis | |
2464 | @item @emph{Description}: | |
2465 | Create an allocator that uses the specified memory space and has the specified | |
2466 | traits; if an allocator that fulfills the requirements cannot be created, | |
2467 | @code{omp_null_allocator} is returned. | |
2468 | ||
2469 | The predefined memory spaces and available traits can be found at | |
2470 | @ref{OMP_ALLOCATOR}, where the trait names have to be be prefixed by | |
2471 | @code{omp_atk_} (e.g. @code{omp_atk_pinned}) and the named trait values by | |
2472 | @code{omp_atv_} (e.g. @code{omp_atv_true}); additionally, @code{omp_atv_default} | |
2473 | may be used as trait value to specify that the default value should be used. | |
2474 | ||
2475 | @item @emph{C/C++}: | |
2476 | @multitable @columnfractions .20 .80 | |
2477 | @item @emph{Prototype}: @tab @code{omp_allocator_handle_t omp_init_allocator(} | |
2478 | @item @tab @code{ omp_memspace_handle_t memspace,} | |
2479 | @item @tab @code{ int ntraits,} | |
2480 | @item @tab @code{ const omp_alloctrait_t traits[]);} | |
2481 | @end multitable | |
2482 | ||
2483 | @item @emph{Fortran}: | |
2484 | @multitable @columnfractions .20 .80 | |
2485 | @item @emph{Interface}: @tab @code{function omp_init_allocator(memspace, ntraits, traits)} | |
bc238c40 TB |
2486 | @item @tab @code{integer (omp_allocator_handle_kind) :: omp_init_allocator} |
2487 | @item @tab @code{integer (omp_memspace_handle_kind), intent(in) :: memspace} | |
971f119f TB |
2488 | @item @tab @code{integer, intent(in) :: ntraits} |
2489 | @item @tab @code{type (omp_alloctrait), intent(in) :: traits(*)} | |
2490 | @end multitable | |
2491 | ||
2492 | @item @emph{See also}: | |
2493 | @ref{OMP_ALLOCATOR}, @ref{Memory allocation}, @ref{omp_destroy_allocator} | |
2494 | ||
2495 | @item @emph{Reference}: | |
2496 | @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.7.2 | |
2497 | @end table | |
2498 | ||
2499 | ||
2500 | ||
2501 | @node omp_destroy_allocator | |
2502 | @subsection @code{omp_destroy_allocator} -- Destroy an allocator | |
2503 | @table @asis | |
2504 | @item @emph{Description}: | |
2505 | Releases all resources used by a memory allocator, which must not represent | |
2506 | a predefined memory allocator. Accessing memory after its allocator has been | |
2507 | destroyed has unspecified behavior. Passing @code{omp_null_allocator} to the | |
15886c03 | 2508 | routine is permitted but has no effect. |
971f119f TB |
2509 | |
2510 | ||
2511 | @item @emph{C/C++}: | |
2512 | @multitable @columnfractions .20 .80 | |
2513 | @item @emph{Prototype}: @tab @code{void omp_destroy_allocator (omp_allocator_handle_t allocator);} | |
2514 | @end multitable | |
2515 | ||
2516 | @item @emph{Fortran}: | |
2517 | @multitable @columnfractions .20 .80 | |
2518 | @item @emph{Interface}: @tab @code{subroutine omp_destroy_allocator(allocator)} | |
bc238c40 | 2519 | @item @tab @code{integer (omp_allocator_handle_kind), intent(in) :: allocator} |
971f119f TB |
2520 | @end multitable |
2521 | ||
2522 | @item @emph{See also}: | |
2523 | @ref{omp_init_allocator} | |
2524 | ||
2525 | @item @emph{Reference}: | |
2526 | @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.7.3 | |
2527 | @end table | |
2528 | ||
2529 | ||
2530 | ||
2531 | @node omp_set_default_allocator | |
2532 | @subsection @code{omp_set_default_allocator} -- Set the default allocator | |
2533 | @table @asis | |
2534 | @item @emph{Description}: | |
2535 | Sets the default allocator that is used when no allocator has been specified | |
2536 | in the @code{allocate} or @code{allocator} clause or if an OpenMP memory | |
2537 | routine is invoked with the @code{omp_null_allocator} allocator. | |
2538 | ||
2539 | @item @emph{C/C++}: | |
2540 | @multitable @columnfractions .20 .80 | |
2541 | @item @emph{Prototype}: @tab @code{void omp_set_default_allocator(omp_allocator_handle_t allocator);} | |
2542 | @end multitable | |
2543 | ||
2544 | @item @emph{Fortran}: | |
2545 | @multitable @columnfractions .20 .80 | |
2546 | @item @emph{Interface}: @tab @code{subroutine omp_set_default_allocator(allocator)} | |
bc238c40 | 2547 | @item @tab @code{integer (omp_allocator_handle_kind), intent(in) :: allocator} |
971f119f TB |
2548 | @end multitable |
2549 | ||
2550 | @item @emph{See also}: | |
2551 | @ref{omp_get_default_allocator}, @ref{omp_init_allocator}, @ref{OMP_ALLOCATOR}, | |
2552 | @ref{Memory allocation} | |
2553 | ||
2554 | @item @emph{Reference}: | |
2555 | @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.7.4 | |
2556 | @end table | |
2557 | ||
2558 | ||
2559 | ||
2560 | @node omp_get_default_allocator | |
2561 | @subsection @code{omp_get_default_allocator} -- Get the default allocator | |
2562 | @table @asis | |
2563 | @item @emph{Description}: | |
2564 | The routine returns the default allocator that is used when no allocator has | |
2565 | been specified in the @code{allocate} or @code{allocator} clause or if an | |
2566 | OpenMP memory routine is invoked with the @code{omp_null_allocator} allocator. | |
2567 | ||
2568 | @item @emph{C/C++}: | |
2569 | @multitable @columnfractions .20 .80 | |
2570 | @item @emph{Prototype}: @tab @code{omp_allocator_handle_t omp_get_default_allocator();} | |
2571 | @end multitable | |
2572 | ||
2573 | @item @emph{Fortran}: | |
2574 | @multitable @columnfractions .20 .80 | |
2575 | @item @emph{Interface}: @tab @code{function omp_get_default_allocator()} | |
bc238c40 | 2576 | @item @tab @code{integer (omp_allocator_handle_kind) :: omp_get_default_allocator} |
971f119f TB |
2577 | @end multitable |
2578 | ||
2579 | @item @emph{See also}: | |
2580 | @ref{omp_set_default_allocator}, @ref{OMP_ALLOCATOR} | |
2581 | ||
2582 | @item @emph{Reference}: | |
2583 | @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.7.5 | |
2584 | @end table | |
2585 | ||
2586 | ||
506f068e | 2587 | |
bc238c40 TB |
2588 | @node omp_alloc |
2589 | @subsection @code{omp_alloc} -- Memory allocation with an allocator | |
2590 | @table @asis | |
2591 | @item @emph{Description}: | |
2592 | Allocate memory with the specified allocator, which can either be a predefined | |
2593 | allocator, an allocator handle or @code{omp_null_allocator}. If the allocators | |
2594 | is @code{omp_null_allocator}, the allocator specified by the | |
2595 | @var{def-allocator-var} ICV is used. @var{size} must be a nonnegative number | |
2596 | denoting the number of bytes to be allocated; if @var{size} is zero, | |
2597 | @code{omp_alloc} will return a null pointer. If successful, a pointer to the | |
2598 | allocated memory is returned, otherwise the @code{fallback} trait of the | |
2599 | allocator determines the behavior. The content of the allocated memory is | |
2600 | unspecified. | |
2601 | ||
2602 | In @code{target} regions, either the @code{dynamic_allocators} clause must | |
2603 | appear on a @code{requires} directive in the same compilation unit -- or the | |
2604 | @var{allocator} argument may only be a constant expression with the value of | |
2605 | one of the predefined allocators and may not be @code{omp_null_allocator}. | |
2606 | ||
2607 | Memory allocated by @code{omp_alloc} must be freed using @code{omp_free}. | |
2608 | ||
2609 | @item @emph{C}: | |
2610 | @multitable @columnfractions .20 .80 | |
2611 | @item @emph{Prototype}: @tab @code{void* omp_alloc(size_t size,} | |
2612 | @item @tab @code{ omp_allocator_handle_t allocator)} | |
2613 | @end multitable | |
2614 | ||
2615 | @item @emph{C++}: | |
2616 | @multitable @columnfractions .20 .80 | |
2617 | @item @emph{Prototype}: @tab @code{void* omp_alloc(size_t size,} | |
2618 | @item @tab @code{ omp_allocator_handle_t allocator=omp_null_allocator)} | |
2619 | @end multitable | |
2620 | ||
2621 | @item @emph{Fortran}: | |
2622 | @multitable @columnfractions .20 .80 | |
2623 | @item @emph{Interface}: @tab @code{type(c_ptr) function omp_alloc(size, allocator) bind(C)} | |
2624 | @item @tab @code{use, intrinsic :: iso_c_binding, only : c_ptr, c_size_t} | |
2625 | @item @tab @code{integer (c_size_t), value :: size} | |
2626 | @item @tab @code{integer (omp_allocator_handle_kind), value :: allocator} | |
2627 | @end multitable | |
2628 | ||
2629 | @item @emph{See also}: | |
2630 | @ref{OMP_ALLOCATOR}, @ref{Memory allocation}, @ref{omp_set_default_allocator}, | |
2631 | @ref{omp_free}, @ref{omp_init_allocator} | |
2632 | ||
2633 | @item @emph{Reference}: | |
2634 | @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.7.6 | |
2635 | @end table | |
2636 | ||
2637 | ||
2638 | ||
2639 | @node omp_aligned_alloc | |
2640 | @subsection @code{omp_aligned_alloc} -- Memory allocation with an allocator and alignment | |
2641 | @table @asis | |
2642 | @item @emph{Description}: | |
2643 | Allocate memory with the specified allocator, which can either be a predefined | |
2644 | allocator, an allocator handle or @code{omp_null_allocator}. If the allocators | |
2645 | is @code{omp_null_allocator}, the allocator specified by the | |
2646 | @var{def-allocator-var} ICV is used. @var{alignment} must be a positive power | |
2647 | of two and @var{size} must be a nonnegative number that is a multiple of the | |
2648 | alignment and denotes the number of bytes to be allocated; if @var{size} is | |
2649 | zero, @code{omp_aligned_alloc} will return a null pointer. The alignment will | |
2650 | be at least the maximal value required by @code{alignment} trait of the | |
2651 | allocator and the value of the passed @var{alignment} argument. If successful, | |
2652 | a pointer to the allocated memory is returned, otherwise the @code{fallback} | |
2653 | trait of the allocator determines the behavior. The content of the allocated | |
2654 | memory is unspecified. | |
2655 | ||
2656 | In @code{target} regions, either the @code{dynamic_allocators} clause must | |
2657 | appear on a @code{requires} directive in the same compilation unit -- or the | |
2658 | @var{allocator} argument may only be a constant expression with the value of | |
2659 | one of the predefined allocators and may not be @code{omp_null_allocator}. | |
2660 | ||
2661 | Memory allocated by @code{omp_aligned_alloc} must be freed using | |
2662 | @code{omp_free}. | |
2663 | ||
2664 | @item @emph{C}: | |
2665 | @multitable @columnfractions .20 .80 | |
2666 | @item @emph{Prototype}: @tab @code{void* omp_aligned_alloc(size_t alignment,} | |
2667 | @item @tab @code{ size_t size,} | |
2668 | @item @tab @code{ omp_allocator_handle_t allocator)} | |
2669 | @end multitable | |
2670 | ||
2671 | @item @emph{C++}: | |
2672 | @multitable @columnfractions .20 .80 | |
2673 | @item @emph{Prototype}: @tab @code{void* omp_aligned_alloc(size_t alignment,} | |
2674 | @item @tab @code{ size_t size,} | |
2675 | @item @tab @code{ omp_allocator_handle_t allocator=omp_null_allocator)} | |
2676 | @end multitable | |
2677 | ||
2678 | @item @emph{Fortran}: | |
2679 | @multitable @columnfractions .20 .80 | |
2680 | @item @emph{Interface}: @tab @code{type(c_ptr) function omp_aligned_alloc(alignment, size, allocator) bind(C)} | |
2681 | @item @tab @code{use, intrinsic :: iso_c_binding, only : c_ptr, c_size_t} | |
2682 | @item @tab @code{integer (c_size_t), value :: alignment, size} | |
2683 | @item @tab @code{integer (omp_allocator_handle_kind), value :: allocator} | |
2684 | @end multitable | |
2685 | ||
2686 | @item @emph{See also}: | |
2687 | @ref{OMP_ALLOCATOR}, @ref{Memory allocation}, @ref{omp_set_default_allocator}, | |
2688 | @ref{omp_free}, @ref{omp_init_allocator} | |
2689 | ||
2690 | @item @emph{Reference}: | |
2691 | @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 3.13.6 | |
2692 | @end table | |
2693 | ||
2694 | ||
2695 | ||
2696 | @node omp_free | |
2697 | @subsection @code{omp_free} -- Freeing memory allocated with OpenMP routines | |
2698 | @table @asis | |
2699 | @item @emph{Description}: | |
2700 | The @code{omp_free} routine deallocates memory previously allocated by an | |
2701 | OpenMP memory-management routine. The @var{ptr} argument must point to such | |
2702 | memory or be a null pointer; if it is a null pointer, no operation is | |
2703 | performed. If specified, the @var{allocator} argument must be either the | |
2704 | memory allocator that was used for the allocation or @code{omp_null_allocator}; | |
2705 | if it is @code{omp_null_allocator}, the implementation will determine the value | |
2706 | automatically. | |
2707 | ||
2708 | Calling @code{omp_free} invokes undefined behavior if the memory | |
2709 | was already deallocated or when the used allocator has already been destroyed. | |
2710 | ||
2711 | @item @emph{C}: | |
2712 | @multitable @columnfractions .20 .80 | |
2713 | @item @emph{Prototype}: @tab @code{void omp_free(void *ptr,} | |
2714 | @item @tab @code{ omp_allocator_handle_t allocator)} | |
2715 | @end multitable | |
2716 | ||
2717 | @item @emph{C++}: | |
2718 | @multitable @columnfractions .20 .80 | |
2719 | @item @emph{Prototype}: @tab @code{void omp_free(void *ptr,} | |
2720 | @item @tab @code{ omp_allocator_handle_t allocator=omp_null_allocator)} | |
2721 | @end multitable | |
2722 | ||
2723 | @item @emph{Fortran}: | |
2724 | @multitable @columnfractions .20 .80 | |
2725 | @item @emph{Interface}: @tab @code{subroutine omp_free(ptr, allocator) bind(C)} | |
2726 | @item @tab @code{use, intrinsic :: iso_c_binding, only : c_ptr} | |
2727 | @item @tab @code{type (c_ptr), value :: ptr} | |
2728 | @item @tab @code{integer (omp_allocator_handle_kind), value :: allocator} | |
2729 | @end multitable | |
2730 | ||
2731 | @item @emph{See also}: | |
2732 | @ref{omp_alloc}, @ref{omp_aligned_alloc}, @ref{omp_calloc}, | |
2733 | @ref{omp_aligned_calloc}, @ref{omp_realloc} | |
2734 | ||
2735 | @item @emph{Reference}: | |
2736 | @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.7.7 | |
2737 | @end table | |
2738 | ||
2739 | ||
2740 | ||
2741 | @node omp_calloc | |
2742 | @subsection @code{omp_calloc} -- Allocate nullified memory with an allocator | |
2743 | @table @asis | |
2744 | @item @emph{Description}: | |
2745 | Allocate zero-initialized memory with the specified allocator, which can either | |
2746 | be a predefined allocator, an allocator handle or @code{omp_null_allocator}. If | |
2747 | the allocators is @code{omp_null_allocator}, the allocator specified by the | |
2748 | @var{def-allocator-var} ICV is used. The to-be allocated memory is for an | |
2749 | array with @var{nmemb} elements, each having a size of @var{size} bytes. Both | |
2750 | @var{nmemb} and @var{size} must be nonnegative numbers; if either of them is | |
2751 | zero, @code{omp_calloc} will return a null pointer. If successful, a pointer to | |
2752 | the zero-initialized allocated memory is returned, otherwise the @code{fallback} | |
2753 | trait of the allocator determines the behavior. | |
2754 | ||
2755 | In @code{target} regions, either the @code{dynamic_allocators} clause must | |
2756 | appear on a @code{requires} directive in the same compilation unit -- or the | |
2757 | @var{allocator} argument may only be a constant expression with the value of | |
2758 | one of the predefined allocators and may not be @code{omp_null_allocator}. | |
2759 | ||
2760 | Memory allocated by @code{omp_calloc} must be freed using @code{omp_free}. | |
2761 | ||
2762 | @item @emph{C}: | |
2763 | @multitable @columnfractions .20 .80 | |
2764 | @item @emph{Prototype}: @tab @code{void* omp_calloc(size_t nmemb, size_t size,} | |
2765 | @item @tab @code{ omp_allocator_handle_t allocator)} | |
2766 | @end multitable | |
2767 | ||
2768 | @item @emph{C++}: | |
2769 | @multitable @columnfractions .20 .80 | |
2770 | @item @emph{Prototype}: @tab @code{void* omp_calloc(size_t nmemb, size_t size,} | |
2771 | @item @tab @code{ omp_allocator_handle_t allocator=omp_null_allocator)} | |
2772 | @end multitable | |
2773 | ||
2774 | @item @emph{Fortran}: | |
2775 | @multitable @columnfractions .20 .80 | |
2776 | @item @emph{Interface}: @tab @code{type(c_ptr) function omp_calloc(nmemb, size, allocator) bind(C)} | |
2777 | @item @tab @code{use, intrinsic :: iso_c_binding, only : c_ptr, c_size_t} | |
2778 | @item @tab @code{integer (c_size_t), value :: nmemb, size} | |
2779 | @item @tab @code{integer (omp_allocator_handle_kind), value :: allocator} | |
2780 | @end multitable | |
2781 | ||
2782 | @item @emph{See also}: | |
2783 | @ref{OMP_ALLOCATOR}, @ref{Memory allocation}, @ref{omp_set_default_allocator}, | |
2784 | @ref{omp_free}, @ref{omp_init_allocator} | |
2785 | ||
2786 | @item @emph{Reference}: | |
2787 | @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 3.13.8 | |
2788 | @end table | |
2789 | ||
2790 | ||
2791 | ||
2792 | @node omp_aligned_calloc | |
2793 | @subsection @code{omp_aligned_calloc} -- Allocate aligned nullified memory with an allocator | |
2794 | @table @asis | |
2795 | @item @emph{Description}: | |
2796 | Allocate zero-initialized memory with the specified allocator, which can either | |
2797 | be a predefined allocator, an allocator handle or @code{omp_null_allocator}. If | |
2798 | the allocators is @code{omp_null_allocator}, the allocator specified by the | |
2799 | @var{def-allocator-var} ICV is used. The to-be allocated memory is for an | |
2800 | array with @var{nmemb} elements, each having a size of @var{size} bytes. Both | |
2801 | @var{nmemb} and @var{size} must be nonnegative numbers; if either of them is | |
2802 | zero, @code{omp_aligned_calloc} will return a null pointer. @var{alignment} | |
2803 | must be a positive power of two and @var{size} must be a multiple of the | |
2804 | alignment; the alignment will be at least the maximal value required by | |
2805 | @code{alignment} trait of the allocator and the value of the passed | |
2806 | @var{alignment} argument. If successful, a pointer to the zero-initialized | |
2807 | allocated memory is returned, otherwise the @code{fallback} trait of the | |
2808 | allocator determines the behavior. | |
2809 | ||
2810 | In @code{target} regions, either the @code{dynamic_allocators} clause must | |
2811 | appear on a @code{requires} directive in the same compilation unit -- or the | |
2812 | @var{allocator} argument may only be a constant expression with the value of | |
2813 | one of the predefined allocators and may not be @code{omp_null_allocator}. | |
2814 | ||
2815 | Memory allocated by @code{omp_aligned_calloc} must be freed using | |
2816 | @code{omp_free}. | |
2817 | ||
2818 | @item @emph{C}: | |
2819 | @multitable @columnfractions .20 .80 | |
2820 | @item @emph{Prototype}: @tab @code{void* omp_aligned_calloc(size_t nmemb, size_t size,} | |
2821 | @item @tab @code{ omp_allocator_handle_t allocator)} | |
2822 | @end multitable | |
2823 | ||
2824 | @item @emph{C++}: | |
2825 | @multitable @columnfractions .20 .80 | |
2826 | @item @emph{Prototype}: @tab @code{void* omp_aligned_calloc(size_t nmemb, size_t size,} | |
2827 | @item @tab @code{ omp_allocator_handle_t allocator=omp_null_allocator)} | |
2828 | @end multitable | |
2829 | ||
2830 | @item @emph{Fortran}: | |
2831 | @multitable @columnfractions .20 .80 | |
2832 | @item @emph{Interface}: @tab @code{type(c_ptr) function omp_aligned_calloc(nmemb, size, allocator) bind(C)} | |
2833 | @item @tab @code{use, intrinsic :: iso_c_binding, only : c_ptr, c_size_t} | |
2834 | @item @tab @code{integer (c_size_t), value :: nmemb, size} | |
2835 | @item @tab @code{integer (omp_allocator_handle_kind), value :: allocator} | |
2836 | @end multitable | |
2837 | ||
2838 | @item @emph{See also}: | |
2839 | @ref{OMP_ALLOCATOR}, @ref{Memory allocation}, @ref{omp_set_default_allocator}, | |
2840 | @ref{omp_free}, @ref{omp_init_allocator} | |
2841 | ||
2842 | @item @emph{Reference}: | |
2843 | @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 3.13.8 | |
2844 | @end table | |
2845 | ||
2846 | ||
2847 | ||
2848 | @node omp_realloc | |
2849 | @subsection @code{omp_realloc} -- Reallocate memory allocated with OpenMP routines | |
2850 | @table @asis | |
2851 | @item @emph{Description}: | |
2852 | The @code{omp_realloc} routine deallocates memory to which @var{ptr} points to | |
2853 | and allocates new memory with the specified @var{allocator} argument; the | |
2854 | new memory will have the content of the old memory up to the minimum of the | |
2855 | old size and the new @var{size}, otherwise the content of the returned memory | |
2856 | is unspecified. If the new allocator is the same as the old one, the routine | |
2857 | tries to resize the existing memory allocation, returning the same address as | |
2858 | @var{ptr} if successful. @var{ptr} must point to memory allocated by an OpenMP | |
2859 | memory-management routine. | |
2860 | ||
2861 | The @var{allocator} and @var{free_allocator} arguments must be a predefined | |
2862 | allocator, an allocator handle or @code{omp_null_allocator}. If | |
2863 | @var{free_allocator} is @code{omp_null_allocator}, the implementation | |
2864 | automatically determines the allocator used for the allocation of @var{ptr}. | |
2865 | If @var{allocator} is @code{omp_null_allocator} and @var{ptr} is is not a | |
2866 | null pointer, the same allocator as @code{free_allocator} is used and | |
2867 | when @var{ptr} is a null pointer the allocator specified by the | |
2868 | @var{def-allocator-var} ICV is used. | |
2869 | ||
2870 | The @var{size} must be a nonnegative number denoting the number of bytes to be | |
2871 | allocated; if @var{size} is zero, @code{omp_realloc} will return free the | |
2872 | memory and return a null pointer. When @var{size} is nonzero: if successful, | |
2873 | a pointer to the allocated memory is returned, otherwise the @code{fallback} | |
2874 | trait of the allocator determines the behavior. | |
2875 | ||
2876 | In @code{target} regions, either the @code{dynamic_allocators} clause must | |
2877 | appear on a @code{requires} directive in the same compilation unit -- or the | |
2878 | @var{free_allocator} and @var{allocator} arguments may only be a constant | |
2879 | expression with the value of one of the predefined allocators and may not be | |
2880 | @code{omp_null_allocator}. | |
2881 | ||
2882 | Memory allocated by @code{omp_realloc} must be freed using @code{omp_free}. | |
2883 | Calling @code{omp_free} invokes undefined behavior if the memory | |
2884 | was already deallocated or when the used allocator has already been destroyed. | |
2885 | ||
2886 | @item @emph{C}: | |
2887 | @multitable @columnfractions .20 .80 | |
2888 | @item @emph{Prototype}: @tab @code{void* omp_realloc(void *ptr, size_t size,} | |
2889 | @item @tab @code{ omp_allocator_handle_t allocator,} | |
2890 | @item @tab @code{ omp_allocator_handle_t free_allocator)} | |
2891 | @end multitable | |
2892 | ||
2893 | @item @emph{C++}: | |
2894 | @multitable @columnfractions .20 .80 | |
2895 | @item @emph{Prototype}: @tab @code{void* omp_realloc(void *ptr, size_t size,} | |
2896 | @item @tab @code{ omp_allocator_handle_t allocator=omp_null_allocator,} | |
2897 | @item @tab @code{ omp_allocator_handle_t free_allocator=omp_null_allocator)} | |
2898 | @end multitable | |
2899 | ||
2900 | @item @emph{Fortran}: | |
2901 | @multitable @columnfractions .20 .80 | |
2902 | @item @emph{Interface}: @tab @code{type(c_ptr) function omp_realloc(ptr, size, allocator, free_allocator) bind(C)} | |
2903 | @item @tab @code{use, intrinsic :: iso_c_binding, only : c_ptr, c_size_t} | |
2904 | @item @tab @code{type(C_ptr), value :: ptr} | |
2905 | @item @tab @code{integer (c_size_t), value :: size} | |
2906 | @item @tab @code{integer (omp_allocator_handle_kind), value :: allocator, free_allocator} | |
2907 | @end multitable | |
2908 | ||
2909 | @item @emph{See also}: | |
2910 | @ref{OMP_ALLOCATOR}, @ref{Memory allocation}, @ref{omp_set_default_allocator}, | |
2911 | @ref{omp_free}, @ref{omp_init_allocator} | |
2912 | ||
2913 | @item @emph{Reference}: | |
2914 | @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.7.9 | |
2915 | @end table | |
2916 | ||
2917 | ||
2918 | ||
506f068e TB |
2919 | @c @node Tool Control Routine |
2920 | @c | |
2921 | @c FIXME | |
2922 | ||
2923 | @c @node Environment Display Routine | |
2924 | @c @section Environment Display Routine | |
2925 | @c | |
2926 | @c Routine to display the OpenMP number and the initial value of ICVs. | |
2927 | @c It has C linkage and do not throw exceptions. | |
2928 | @c | |
2929 | @c menu | |
2930 | @c * omp_display_env:: <fixme> | |
2931 | @c end menu | |
2932 | ||
d77de738 ML |
2933 | @c --------------------------------------------------------------------- |
2934 | @c OpenMP Environment Variables | |
2935 | @c --------------------------------------------------------------------- | |
2936 | ||
2937 | @node Environment Variables | |
2938 | @chapter OpenMP Environment Variables | |
2939 | ||
2940 | The environment variables which beginning with @env{OMP_} are defined by | |
2cd0689a TB |
2941 | section 4 of the OpenMP specification in version 4.5 or in a later version |
2942 | of the specification, while those beginning with @env{GOMP_} are GNU extensions. | |
2943 | Most @env{OMP_} environment variables have an associated internal control | |
2944 | variable (ICV). | |
2945 | ||
2946 | For any OpenMP environment variable that sets an ICV and is neither | |
2947 | @code{OMP_DEFAULT_DEVICE} nor has global ICV scope, associated | |
2948 | device-specific environment variables exist. For them, the environment | |
2949 | variable without suffix affects the host. The suffix @code{_DEV_} followed | |
2950 | by a non-negative device number less that the number of available devices sets | |
2951 | the ICV for the corresponding device. The suffix @code{_DEV} sets the ICV | |
2952 | of all non-host devices for which a device-specific corresponding environment | |
2953 | variable has not been set while the @code{_ALL} suffix sets the ICV of all | |
2954 | host and non-host devices for which a more specific corresponding environment | |
2955 | variable is not set. | |
d77de738 ML |
2956 | |
2957 | @menu | |
73a0d3bf TB |
2958 | * OMP_ALLOCATOR:: Set the default allocator |
2959 | * OMP_AFFINITY_FORMAT:: Set the format string used for affinity display | |
d77de738 | 2960 | * OMP_CANCELLATION:: Set whether cancellation is activated |
73a0d3bf | 2961 | * OMP_DISPLAY_AFFINITY:: Display thread affinity information |
d77de738 ML |
2962 | * OMP_DISPLAY_ENV:: Show OpenMP version and environment variables |
2963 | * OMP_DEFAULT_DEVICE:: Set the device used in target regions | |
2964 | * OMP_DYNAMIC:: Dynamic adjustment of threads | |
2965 | * OMP_MAX_ACTIVE_LEVELS:: Set the maximum number of nested parallel regions | |
2966 | * OMP_MAX_TASK_PRIORITY:: Set the maximum task priority value | |
2967 | * OMP_NESTED:: Nested parallel regions | |
2968 | * OMP_NUM_TEAMS:: Specifies the number of teams to use by teams region | |
2969 | * OMP_NUM_THREADS:: Specifies the number of threads to use | |
0b9bd33d JJ |
2970 | * OMP_PROC_BIND:: Whether threads may be moved between CPUs |
2971 | * OMP_PLACES:: Specifies on which CPUs the threads should be placed | |
d77de738 ML |
2972 | * OMP_STACKSIZE:: Set default thread stack size |
2973 | * OMP_SCHEDULE:: How threads are scheduled | |
bc238c40 | 2974 | * OMP_TARGET_OFFLOAD:: Controls offloading behavior |
d77de738 ML |
2975 | * OMP_TEAMS_THREAD_LIMIT:: Set the maximum number of threads imposed by teams |
2976 | * OMP_THREAD_LIMIT:: Set the maximum number of threads | |
2977 | * OMP_WAIT_POLICY:: How waiting threads are handled | |
2978 | * GOMP_CPU_AFFINITY:: Bind threads to specific CPUs | |
2979 | * GOMP_DEBUG:: Enable debugging output | |
2980 | * GOMP_STACKSIZE:: Set default thread stack size | |
2981 | * GOMP_SPINCOUNT:: Set the busy-wait spin count | |
2982 | * GOMP_RTEMS_THREAD_POOLS:: Set the RTEMS specific thread pools | |
2983 | @end menu | |
2984 | ||
2985 | ||
73a0d3bf TB |
2986 | @node OMP_ALLOCATOR |
2987 | @section @env{OMP_ALLOCATOR} -- Set the default allocator | |
2988 | @cindex Environment Variable | |
2989 | @table @asis | |
971f119f | 2990 | @item @emph{ICV:} @var{def-allocator-var} |
2cd0689a | 2991 | @item @emph{Scope:} data environment |
73a0d3bf TB |
2992 | @item @emph{Description}: |
2993 | Sets the default allocator that is used when no allocator has been specified | |
2994 | in the @code{allocate} or @code{allocator} clause or if an OpenMP memory | |
2995 | routine is invoked with the @code{omp_null_allocator} allocator. | |
2996 | If unset, @code{omp_default_mem_alloc} is used. | |
2997 | ||
2998 | The value can either be a predefined allocator or a predefined memory space | |
2999 | or a predefined memory space followed by a colon and a comma-separated list | |
3000 | of memory trait and value pairs, separated by @code{=}. | |
3001 | ||
2cd0689a TB |
3002 | Note: The corresponding device environment variables are currently not |
3003 | supported. Therefore, the non-host @var{def-allocator-var} ICVs are always | |
3004 | initialized to @code{omp_default_mem_alloc}. However, on all devices, | |
3005 | the @code{omp_set_default_allocator} API routine can be used to change | |
3006 | value. | |
3007 | ||
73a0d3bf | 3008 | @multitable @columnfractions .45 .45 |
a85a106c | 3009 | @headitem Predefined allocators @tab Associated predefined memory spaces |
73a0d3bf TB |
3010 | @item omp_default_mem_alloc @tab omp_default_mem_space |
3011 | @item omp_large_cap_mem_alloc @tab omp_large_cap_mem_space | |
3012 | @item omp_const_mem_alloc @tab omp_const_mem_space | |
3013 | @item omp_high_bw_mem_alloc @tab omp_high_bw_mem_space | |
3014 | @item omp_low_lat_mem_alloc @tab omp_low_lat_mem_space | |
3015 | @item omp_cgroup_mem_alloc @tab -- | |
3016 | @item omp_pteam_mem_alloc @tab -- | |
3017 | @item omp_thread_mem_alloc @tab -- | |
3018 | @end multitable | |
3019 | ||
a85a106c TB |
3020 | The predefined allocators use the default values for the traits, |
3021 | as listed below. Except that the last three allocators have the | |
3022 | @code{access} trait set to @code{cgroup}, @code{pteam}, and | |
3023 | @code{thread}, respectively. | |
3024 | ||
3025 | @multitable @columnfractions .25 .40 .25 | |
3026 | @headitem Trait @tab Allowed values @tab Default value | |
73a0d3bf TB |
3027 | @item @code{sync_hint} @tab @code{contended}, @code{uncontended}, |
3028 | @code{serialized}, @code{private} | |
a85a106c | 3029 | @tab @code{contended} |
73a0d3bf | 3030 | @item @code{alignment} @tab Positive integer being a power of two |
a85a106c | 3031 | @tab 1 byte |
73a0d3bf TB |
3032 | @item @code{access} @tab @code{all}, @code{cgroup}, |
3033 | @code{pteam}, @code{thread} | |
a85a106c | 3034 | @tab @code{all} |
73a0d3bf | 3035 | @item @code{pool_size} @tab Positive integer |
a85a106c | 3036 | @tab See @ref{Memory allocation} |
73a0d3bf TB |
3037 | @item @code{fallback} @tab @code{default_mem_fb}, @code{null_fb}, |
3038 | @code{abort_fb}, @code{allocator_fb} | |
a85a106c | 3039 | @tab See below |
73a0d3bf | 3040 | @item @code{fb_data} @tab @emph{unsupported as it needs an allocator handle} |
a85a106c | 3041 | @tab (none) |
73a0d3bf | 3042 | @item @code{pinned} @tab @code{true}, @code{false} |
a85a106c | 3043 | @tab @code{false} |
73a0d3bf TB |
3044 | @item @code{partition} @tab @code{environment}, @code{nearest}, |
3045 | @code{blocked}, @code{interleaved} | |
a85a106c | 3046 | @tab @code{environment} |
73a0d3bf TB |
3047 | @end multitable |
3048 | ||
a85a106c TB |
3049 | For the @code{fallback} trait, the default value is @code{null_fb} for the |
3050 | @code{omp_default_mem_alloc} allocator and any allocator that is associated | |
3051 | with device memory; for all other other allocators, it is @code{default_mem_fb} | |
3052 | by default. | |
3053 | ||
73a0d3bf TB |
3054 | Examples: |
3055 | @smallexample | |
3056 | OMP_ALLOCATOR=omp_high_bw_mem_alloc | |
3057 | OMP_ALLOCATOR=omp_large_cap_mem_space | |
506f068e | 3058 | OMP_ALLOCATOR=omp_low_lat_mem_space:pinned=true,partition=nearest |
73a0d3bf TB |
3059 | @end smallexample |
3060 | ||
a85a106c | 3061 | @item @emph{See also}: |
971f119f TB |
3062 | @ref{Memory allocation}, @ref{omp_get_default_allocator}, |
3063 | @ref{omp_set_default_allocator} | |
73a0d3bf TB |
3064 | |
3065 | @item @emph{Reference}: | |
3066 | @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 6.21 | |
3067 | @end table | |
3068 | ||
3069 | ||
3070 | ||
3071 | @node OMP_AFFINITY_FORMAT | |
3072 | @section @env{OMP_AFFINITY_FORMAT} -- Set the format string used for affinity display | |
3073 | @cindex Environment Variable | |
3074 | @table @asis | |
2cd0689a TB |
3075 | @item @emph{ICV:} @var{affinity-format-var} |
3076 | @item @emph{Scope:} device | |
73a0d3bf TB |
3077 | @item @emph{Description}: |
3078 | Sets the format string used when displaying OpenMP thread affinity information. | |
3079 | Special values are output using @code{%} followed by an optional size | |
3080 | specification and then either the single-character field type or its long | |
15886c03 | 3081 | name enclosed in curly braces; using @code{%%} displays a literal percent. |
73a0d3bf | 3082 | The size specification consists of an optional @code{0.} or @code{.} followed |
450b05ce | 3083 | by a positive integer, specifying the minimal width of the output. With |
73a0d3bf TB |
3084 | @code{0.} and numerical values, the output is padded with zeros on the left; |
3085 | with @code{.}, the output is padded by spaces on the left; otherwise, the | |
3086 | output is padded by spaces on the right. If unset, the value is | |
3087 | ``@code{level %L thread %i affinity %A}''. | |
3088 | ||
3089 | Supported field types are: | |
3090 | ||
3091 | @multitable @columnfractions .10 .25 .60 | |
3092 | @item t @tab team_num @tab value returned by @code{omp_get_team_num} | |
3093 | @item T @tab num_teams @tab value returned by @code{omp_get_num_teams} | |
3094 | @item L @tab nesting_level @tab value returned by @code{omp_get_level} | |
3095 | @item n @tab thread_num @tab value returned by @code{omp_get_thread_num} | |
3096 | @item N @tab num_threads @tab value returned by @code{omp_get_num_threads} | |
3097 | @item a @tab ancestor_tnum | |
3098 | @tab value returned by | |
3099 | @code{omp_get_ancestor_thread_num(omp_get_level()-1)} | |
3100 | @item H @tab host @tab name of the host that executes the thread | |
450b05ce TB |
3101 | @item P @tab process_id @tab process identifier |
3102 | @item i @tab native_thread_id @tab native thread identifier | |
73a0d3bf TB |
3103 | @item A @tab thread_affinity |
3104 | @tab comma separated list of integer values or ranges, representing the | |
3105 | processors on which a process might execute, subject to affinity | |
3106 | mechanisms | |
3107 | @end multitable | |
3108 | ||
3109 | For instance, after setting | |
3110 | ||
3111 | @smallexample | |
3112 | OMP_AFFINITY_FORMAT="%0.2a!%n!%.4L!%N;%.2t;%0.2T;%@{team_num@};%@{num_teams@};%A" | |
3113 | @end smallexample | |
3114 | ||
3115 | with either @code{OMP_DISPLAY_AFFINITY} being set or when calling | |
3116 | @code{omp_display_affinity} with @code{NULL} or an empty string, the program | |
3117 | might display the following: | |
3118 | ||
3119 | @smallexample | |
3120 | 00!0! 1!4; 0;01;0;1;0-11 | |
3121 | 00!3! 1!4; 0;01;0;1;0-11 | |
3122 | 00!2! 1!4; 0;01;0;1;0-11 | |
3123 | 00!1! 1!4; 0;01;0;1;0-11 | |
3124 | @end smallexample | |
3125 | ||
3126 | @item @emph{See also}: | |
3127 | @ref{OMP_DISPLAY_AFFINITY} | |
3128 | ||
3129 | @item @emph{Reference}: | |
3130 | @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 6.14 | |
3131 | @end table | |
3132 | ||
3133 | ||
3134 | ||
d77de738 ML |
3135 | @node OMP_CANCELLATION |
3136 | @section @env{OMP_CANCELLATION} -- Set whether cancellation is activated | |
3137 | @cindex Environment Variable | |
3138 | @table @asis | |
2cd0689a TB |
3139 | @item @emph{ICV:} @var{cancel-var} |
3140 | @item @emph{Scope:} global | |
d77de738 ML |
3141 | @item @emph{Description}: |
3142 | If set to @code{TRUE}, the cancellation is activated. If set to @code{FALSE} or | |
3143 | if unset, cancellation is disabled and the @code{cancel} construct is ignored. | |
3144 | ||
3145 | @item @emph{See also}: | |
3146 | @ref{omp_get_cancellation} | |
3147 | ||
3148 | @item @emph{Reference}: | |
3149 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.11 | |
3150 | @end table | |
3151 | ||
3152 | ||
3153 | ||
73a0d3bf TB |
3154 | @node OMP_DISPLAY_AFFINITY |
3155 | @section @env{OMP_DISPLAY_AFFINITY} -- Display thread affinity information | |
3156 | @cindex Environment Variable | |
3157 | @table @asis | |
2cd0689a TB |
3158 | @item @emph{ICV:} @var{display-affinity-var} |
3159 | @item @emph{Scope:} global | |
73a0d3bf TB |
3160 | @item @emph{Description}: |
3161 | If set to @code{FALSE} or if unset, affinity displaying is disabled. | |
15886c03 | 3162 | If set to @code{TRUE}, the runtime displays affinity information about |
73a0d3bf TB |
3163 | OpenMP threads in a parallel region upon entering the region and every time |
3164 | any change occurs. | |
3165 | ||
3166 | @item @emph{See also}: | |
3167 | @ref{OMP_AFFINITY_FORMAT} | |
3168 | ||
3169 | @item @emph{Reference}: | |
3170 | @uref{https://www.openmp.org, OpenMP specification v5.0}, Section 6.13 | |
3171 | @end table | |
3172 | ||
3173 | ||
3174 | ||
3175 | ||
d77de738 ML |
3176 | @node OMP_DISPLAY_ENV |
3177 | @section @env{OMP_DISPLAY_ENV} -- Show OpenMP version and environment variables | |
3178 | @cindex Environment Variable | |
3179 | @table @asis | |
2cd0689a TB |
3180 | @item @emph{ICV:} none |
3181 | @item @emph{Scope:} not applicable | |
d77de738 ML |
3182 | @item @emph{Description}: |
3183 | If set to @code{TRUE}, the OpenMP version number and the values | |
3184 | associated with the OpenMP environment variables are printed to @code{stderr}. | |
3185 | If set to @code{VERBOSE}, it additionally shows the value of the environment | |
3186 | variables which are GNU extensions. If undefined or set to @code{FALSE}, | |
15886c03 | 3187 | this information is not shown. |
d77de738 ML |
3188 | |
3189 | ||
3190 | @item @emph{Reference}: | |
3191 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.12 | |
3192 | @end table | |
3193 | ||
3194 | ||
3195 | ||
3196 | @node OMP_DEFAULT_DEVICE | |
3197 | @section @env{OMP_DEFAULT_DEVICE} -- Set the device used in target regions | |
3198 | @cindex Environment Variable | |
3199 | @table @asis | |
2cd0689a TB |
3200 | @item @emph{ICV:} @var{default-device-var} |
3201 | @item @emph{Scope:} data environment | |
d77de738 ML |
3202 | @item @emph{Description}: |
3203 | Set to choose the device which is used in a @code{target} region, unless the | |
3204 | value is overridden by @code{omp_set_default_device} or by a @code{device} | |
3205 | clause. The value shall be the nonnegative device number. If no device with | |
3206 | the given device number exists, the code is executed on the host. If unset, | |
18c8b56c TB |
3207 | @env{OMP_TARGET_OFFLOAD} is @code{mandatory} and no non-host devices are |
3208 | available, it is set to @code{omp_invalid_device}. Otherwise, if unset, | |
15886c03 | 3209 | device number 0 is used. |
d77de738 ML |
3210 | |
3211 | ||
3212 | @item @emph{See also}: | |
3213 | @ref{omp_get_default_device}, @ref{omp_set_default_device}, | |
8bd11fa4 | 3214 | @ref{OMP_TARGET_OFFLOAD} |
d77de738 ML |
3215 | |
3216 | @item @emph{Reference}: | |
8bd11fa4 | 3217 | @uref{https://www.openmp.org, OpenMP specification v5.2}, Section 21.2.7 |
d77de738 ML |
3218 | @end table |
3219 | ||
3220 | ||
3221 | ||
3222 | @node OMP_DYNAMIC | |
3223 | @section @env{OMP_DYNAMIC} -- Dynamic adjustment of threads | |
3224 | @cindex Environment Variable | |
3225 | @table @asis | |
2cd0689a TB |
3226 | @item @emph{ICV:} @var{dyn-var} |
3227 | @item @emph{Scope:} global | |
d77de738 ML |
3228 | @item @emph{Description}: |
3229 | Enable or disable the dynamic adjustment of the number of threads | |
3230 | within a team. The value of this environment variable shall be | |
3231 | @code{TRUE} or @code{FALSE}. If undefined, dynamic adjustment is | |
3232 | disabled by default. | |
3233 | ||
3234 | @item @emph{See also}: | |
3235 | @ref{omp_set_dynamic} | |
3236 | ||
3237 | @item @emph{Reference}: | |
3238 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.3 | |
3239 | @end table | |
3240 | ||
3241 | ||
3242 | ||
3243 | @node OMP_MAX_ACTIVE_LEVELS | |
3244 | @section @env{OMP_MAX_ACTIVE_LEVELS} -- Set the maximum number of nested parallel regions | |
3245 | @cindex Environment Variable | |
3246 | @table @asis | |
2cd0689a TB |
3247 | @item @emph{ICV:} @var{max-active-levels-var} |
3248 | @item @emph{Scope:} data environment | |
d77de738 ML |
3249 | @item @emph{Description}: |
3250 | Specifies the initial value for the maximum number of nested parallel | |
3251 | regions. The value of this variable shall be a positive integer. | |
3252 | If undefined, then if @env{OMP_NESTED} is defined and set to true, or | |
3253 | if @env{OMP_NUM_THREADS} or @env{OMP_PROC_BIND} are defined and set to | |
3254 | a list with more than one item, the maximum number of nested parallel | |
15886c03 TB |
3255 | regions is initialized to the largest number supported, otherwise |
3256 | it is set to one. | |
d77de738 ML |
3257 | |
3258 | @item @emph{See also}: | |
2cd0689a TB |
3259 | @ref{omp_set_max_active_levels}, @ref{OMP_NESTED}, @ref{OMP_PROC_BIND}, |
3260 | @ref{OMP_NUM_THREADS} | |
3261 | ||
d77de738 ML |
3262 | |
3263 | @item @emph{Reference}: | |
3264 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.9 | |
3265 | @end table | |
3266 | ||
3267 | ||
3268 | ||
3269 | @node OMP_MAX_TASK_PRIORITY | |
3270 | @section @env{OMP_MAX_TASK_PRIORITY} -- Set the maximum priority | |
3271 | number that can be set for a task. | |
3272 | @cindex Environment Variable | |
3273 | @table @asis | |
2cd0689a TB |
3274 | @item @emph{ICV:} @var{max-task-priority-var} |
3275 | @item @emph{Scope:} global | |
d77de738 ML |
3276 | @item @emph{Description}: |
3277 | Specifies the initial value for the maximum priority value that can be | |
3278 | set for a task. The value of this variable shall be a non-negative | |
3279 | integer, and zero is allowed. If undefined, the default priority is | |
3280 | 0. | |
3281 | ||
3282 | @item @emph{See also}: | |
3283 | @ref{omp_get_max_task_priority} | |
3284 | ||
3285 | @item @emph{Reference}: | |
3286 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.14 | |
3287 | @end table | |
3288 | ||
3289 | ||
3290 | ||
3291 | @node OMP_NESTED | |
3292 | @section @env{OMP_NESTED} -- Nested parallel regions | |
3293 | @cindex Environment Variable | |
3294 | @cindex Implementation specific setting | |
3295 | @table @asis | |
2cd0689a TB |
3296 | @item @emph{ICV:} @var{max-active-levels-var} |
3297 | @item @emph{Scope:} data environment | |
d77de738 ML |
3298 | @item @emph{Description}: |
3299 | Enable or disable nested parallel regions, i.e., whether team members | |
3300 | are allowed to create new teams. The value of this environment variable | |
3301 | shall be @code{TRUE} or @code{FALSE}. If set to @code{TRUE}, the number | |
15886c03 TB |
3302 | of maximum active nested regions supported is by default set to the |
3303 | maximum supported, otherwise it is set to one. If | |
3304 | @env{OMP_MAX_ACTIVE_LEVELS} is defined, its setting overrides this | |
d77de738 ML |
3305 | setting. If both are undefined, nested parallel regions are enabled if |
3306 | @env{OMP_NUM_THREADS} or @env{OMP_PROC_BINDS} are defined to a list with | |
3307 | more than one item, otherwise they are disabled by default. | |
3308 | ||
2cd0689a TB |
3309 | Note that the @code{OMP_NESTED} environment variable was deprecated in |
3310 | the OpenMP specification 5.2 in favor of @code{OMP_MAX_ACTIVE_LEVELS}. | |
3311 | ||
d77de738 | 3312 | @item @emph{See also}: |
2cd0689a TB |
3313 | @ref{omp_set_max_active_levels}, @ref{omp_set_nested}, |
3314 | @ref{OMP_MAX_ACTIVE_LEVELS} | |
d77de738 ML |
3315 | |
3316 | @item @emph{Reference}: | |
3317 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.6 | |
3318 | @end table | |
3319 | ||
3320 | ||
3321 | ||
3322 | @node OMP_NUM_TEAMS | |
3323 | @section @env{OMP_NUM_TEAMS} -- Specifies the number of teams to use by teams region | |
3324 | @cindex Environment Variable | |
3325 | @table @asis | |
2cd0689a TB |
3326 | @item @emph{ICV:} @var{nteams-var} |
3327 | @item @emph{Scope:} device | |
d77de738 ML |
3328 | @item @emph{Description}: |
3329 | Specifies the upper bound for number of teams to use in teams regions | |
3330 | without explicit @code{num_teams} clause. The value of this variable shall | |
3331 | be a positive integer. If undefined it defaults to 0 which means | |
3332 | implementation defined upper bound. | |
3333 | ||
3334 | @item @emph{See also}: | |
3335 | @ref{omp_set_num_teams} | |
3336 | ||
3337 | @item @emph{Reference}: | |
3338 | @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 6.23 | |
3339 | @end table | |
3340 | ||
3341 | ||
3342 | ||
3343 | @node OMP_NUM_THREADS | |
3344 | @section @env{OMP_NUM_THREADS} -- Specifies the number of threads to use | |
3345 | @cindex Environment Variable | |
3346 | @cindex Implementation specific setting | |
3347 | @table @asis | |
2cd0689a TB |
3348 | @item @emph{ICV:} @var{nthreads-var} |
3349 | @item @emph{Scope:} data environment | |
d77de738 ML |
3350 | @item @emph{Description}: |
3351 | Specifies the default number of threads to use in parallel regions. The | |
3352 | value of this variable shall be a comma-separated list of positive integers; | |
3353 | the value specifies the number of threads to use for the corresponding nested | |
15886c03 | 3354 | level. Specifying more than one item in the list automatically enables |
d77de738 ML |
3355 | nesting by default. If undefined one thread per CPU is used. |
3356 | ||
2cd0689a TB |
3357 | When a list with more than value is specified, it also affects the |
3358 | @var{max-active-levels-var} ICV as described in @ref{OMP_MAX_ACTIVE_LEVELS}. | |
3359 | ||
d77de738 | 3360 | @item @emph{See also}: |
2cd0689a | 3361 | @ref{omp_set_num_threads}, @ref{OMP_MAX_ACTIVE_LEVELS} |
d77de738 ML |
3362 | |
3363 | @item @emph{Reference}: | |
3364 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.2 | |
3365 | @end table | |
3366 | ||
3367 | ||
3368 | ||
3369 | @node OMP_PROC_BIND | |
0b9bd33d | 3370 | @section @env{OMP_PROC_BIND} -- Whether threads may be moved between CPUs |
d77de738 ML |
3371 | @cindex Environment Variable |
3372 | @table @asis | |
2cd0689a TB |
3373 | @item @emph{ICV:} @var{bind-var} |
3374 | @item @emph{Scope:} data environment | |
d77de738 ML |
3375 | @item @emph{Description}: |
3376 | Specifies whether threads may be moved between processors. If set to | |
0b9bd33d | 3377 | @code{TRUE}, OpenMP threads should not be moved; if set to @code{FALSE} |
d77de738 ML |
3378 | they may be moved. Alternatively, a comma separated list with the |
3379 | values @code{PRIMARY}, @code{MASTER}, @code{CLOSE} and @code{SPREAD} can | |
3380 | be used to specify the thread affinity policy for the corresponding nesting | |
3381 | level. With @code{PRIMARY} and @code{MASTER} the worker threads are in the | |
3382 | same place partition as the primary thread. With @code{CLOSE} those are | |
3383 | kept close to the primary thread in contiguous place partitions. And | |
3384 | with @code{SPREAD} a sparse distribution | |
3385 | across the place partitions is used. Specifying more than one item in the | |
15886c03 | 3386 | list automatically enables nesting by default. |
d77de738 | 3387 | |
2cd0689a TB |
3388 | When a list is specified, it also affects the @var{max-active-levels-var} ICV |
3389 | as described in @ref{OMP_MAX_ACTIVE_LEVELS}. | |
3390 | ||
d77de738 ML |
3391 | When undefined, @env{OMP_PROC_BIND} defaults to @code{TRUE} when |
3392 | @env{OMP_PLACES} or @env{GOMP_CPU_AFFINITY} is set and @code{FALSE} otherwise. | |
3393 | ||
3394 | @item @emph{See also}: | |
2cd0689a TB |
3395 | @ref{omp_get_proc_bind}, @ref{GOMP_CPU_AFFINITY}, @ref{OMP_PLACES}, |
3396 | @ref{OMP_MAX_ACTIVE_LEVELS} | |
d77de738 ML |
3397 | |
3398 | @item @emph{Reference}: | |
3399 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.4 | |
3400 | @end table | |
3401 | ||
3402 | ||
3403 | ||
3404 | @node OMP_PLACES | |
0b9bd33d | 3405 | @section @env{OMP_PLACES} -- Specifies on which CPUs the threads should be placed |
d77de738 ML |
3406 | @cindex Environment Variable |
3407 | @table @asis | |
2cd0689a TB |
3408 | @item @emph{ICV:} @var{place-partition-var} |
3409 | @item @emph{Scope:} implicit tasks | |
d77de738 ML |
3410 | @item @emph{Description}: |
3411 | The thread placement can be either specified using an abstract name or by an | |
3412 | explicit list of the places. The abstract names @code{threads}, @code{cores}, | |
3413 | @code{sockets}, @code{ll_caches} and @code{numa_domains} can be optionally | |
3414 | followed by a positive number in parentheses, which denotes the how many places | |
3415 | shall be created. With @code{threads} each place corresponds to a single | |
3416 | hardware thread; @code{cores} to a single core with the corresponding number of | |
3417 | hardware threads; with @code{sockets} the place corresponds to a single | |
3418 | socket; with @code{ll_caches} to a set of cores that shares the last level | |
3419 | cache on the device; and @code{numa_domains} to a set of cores for which their | |
3420 | closest memory on the device is the same memory and at a similar distance from | |
3421 | the cores. The resulting placement can be shown by setting the | |
3422 | @env{OMP_DISPLAY_ENV} environment variable. | |
3423 | ||
3424 | Alternatively, the placement can be specified explicitly as comma-separated | |
3425 | list of places. A place is specified by set of nonnegative numbers in curly | |
3426 | braces, denoting the hardware threads. The curly braces can be omitted | |
3427 | when only a single number has been specified. The hardware threads | |
3428 | belonging to a place can either be specified as comma-separated list of | |
3429 | nonnegative thread numbers or using an interval. Multiple places can also be | |
3430 | either specified by a comma-separated list of places or by an interval. To | |
3431 | specify an interval, a colon followed by the count is placed after | |
3432 | the hardware thread number or the place. Optionally, the length can be | |
3433 | followed by a colon and the stride number -- otherwise a unit stride is | |
3434 | assumed. Placing an exclamation mark (@code{!}) directly before a curly | |
15886c03 TB |
3435 | brace or numbers inside the curly braces (excluding intervals) |
3436 | excludes those hardware threads. | |
d77de738 ML |
3437 | |
3438 | For instance, the following specifies the same places list: | |
3439 | @code{"@{0,1,2@}, @{3,4,6@}, @{7,8,9@}, @{10,11,12@}"}; | |
3440 | @code{"@{0:3@}, @{3:3@}, @{7:3@}, @{10:3@}"}; and @code{"@{0:2@}:4:3"}. | |
3441 | ||
3442 | If @env{OMP_PLACES} and @env{GOMP_CPU_AFFINITY} are unset and | |
3443 | @env{OMP_PROC_BIND} is either unset or @code{false}, threads may be moved | |
3444 | between CPUs following no placement policy. | |
3445 | ||
3446 | @item @emph{See also}: | |
3447 | @ref{OMP_PROC_BIND}, @ref{GOMP_CPU_AFFINITY}, @ref{omp_get_proc_bind}, | |
3448 | @ref{OMP_DISPLAY_ENV} | |
3449 | ||
3450 | @item @emph{Reference}: | |
3451 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.5 | |
3452 | @end table | |
3453 | ||
3454 | ||
3455 | ||
3456 | @node OMP_STACKSIZE | |
3457 | @section @env{OMP_STACKSIZE} -- Set default thread stack size | |
3458 | @cindex Environment Variable | |
3459 | @table @asis | |
2cd0689a TB |
3460 | @item @emph{ICV:} @var{stacksize-var} |
3461 | @item @emph{Scope:} device | |
d77de738 ML |
3462 | @item @emph{Description}: |
3463 | Set the default thread stack size in kilobytes, unless the number | |
3464 | is suffixed by @code{B}, @code{K}, @code{M} or @code{G}, in which | |
3465 | case the size is, respectively, in bytes, kilobytes, megabytes | |
3466 | or gigabytes. This is different from @code{pthread_attr_setstacksize} | |
3467 | which gets the number of bytes as an argument. If the stack size cannot | |
3468 | be set due to system constraints, an error is reported and the initial | |
3469 | stack size is left unchanged. If undefined, the stack size is system | |
3470 | dependent. | |
3471 | ||
2cd0689a TB |
3472 | @item @emph{See also}: |
3473 | @ref{GOMP_STACKSIZE} | |
3474 | ||
d77de738 ML |
3475 | @item @emph{Reference}: |
3476 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.7 | |
3477 | @end table | |
3478 | ||
3479 | ||
3480 | ||
3481 | @node OMP_SCHEDULE | |
3482 | @section @env{OMP_SCHEDULE} -- How threads are scheduled | |
3483 | @cindex Environment Variable | |
3484 | @cindex Implementation specific setting | |
3485 | @table @asis | |
2cd0689a TB |
3486 | @item @emph{ICV:} @var{run-sched-var} |
3487 | @item @emph{Scope:} data environment | |
d77de738 ML |
3488 | @item @emph{Description}: |
3489 | Allows to specify @code{schedule type} and @code{chunk size}. | |
3490 | The value of the variable shall have the form: @code{type[,chunk]} where | |
3491 | @code{type} is one of @code{static}, @code{dynamic}, @code{guided} or @code{auto} | |
3492 | The optional @code{chunk} size shall be a positive integer. If undefined, | |
3493 | dynamic scheduling and a chunk size of 1 is used. | |
3494 | ||
3495 | @item @emph{See also}: | |
3496 | @ref{omp_set_schedule} | |
3497 | ||
3498 | @item @emph{Reference}: | |
3499 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Sections 2.7.1.1 and 4.1 | |
3500 | @end table | |
3501 | ||
3502 | ||
3503 | ||
3504 | @node OMP_TARGET_OFFLOAD | |
bc238c40 | 3505 | @section @env{OMP_TARGET_OFFLOAD} -- Controls offloading behavior |
d77de738 ML |
3506 | @cindex Environment Variable |
3507 | @cindex Implementation specific setting | |
3508 | @table @asis | |
2cd0689a TB |
3509 | @item @emph{ICV:} @var{target-offload-var} |
3510 | @item @emph{Scope:} global | |
d77de738 | 3511 | @item @emph{Description}: |
bc238c40 | 3512 | Specifies the behavior with regard to offloading code to a device. This |
d77de738 ML |
3513 | variable can be set to one of three values - @code{MANDATORY}, @code{DISABLED} |
3514 | or @code{DEFAULT}. | |
3515 | ||
15886c03 | 3516 | If set to @code{MANDATORY}, the program terminates with an error if |
8bd11fa4 TB |
3517 | any device construct or device memory routine uses a device that is unavailable |
3518 | or not supported by the implementation, or uses a non-conforming device number. | |
15886c03 TB |
3519 | If set to @code{DISABLED}, then offloading is disabled and all code runs on |
3520 | the host. If set to @code{DEFAULT}, the program tries offloading to the | |
3521 | device first, then falls back to running code on the host if it cannot. | |
d77de738 | 3522 | |
15886c03 | 3523 | If undefined, then the program behaves as if @code{DEFAULT} was set. |
d77de738 | 3524 | |
15886c03 | 3525 | Note: Even with @code{MANDATORY}, no run-time termination is performed when |
8bd11fa4 TB |
3526 | the device number in a @code{device} clause or argument to a device memory |
3527 | routine is for host, which includes using the device number in the | |
3528 | @var{default-device-var} ICV. However, the initial value of | |
3529 | the @var{default-device-var} ICV is affected by @code{MANDATORY}. | |
3530 | ||
3531 | @item @emph{See also}: | |
3532 | @ref{OMP_DEFAULT_DEVICE} | |
3533 | ||
d77de738 | 3534 | @item @emph{Reference}: |
8bd11fa4 | 3535 | @uref{https://www.openmp.org, OpenMP specification v5.2}, Section 21.2.8 |
d77de738 ML |
3536 | @end table |
3537 | ||
3538 | ||
3539 | ||
3540 | @node OMP_TEAMS_THREAD_LIMIT | |
3541 | @section @env{OMP_TEAMS_THREAD_LIMIT} -- Set the maximum number of threads imposed by teams | |
3542 | @cindex Environment Variable | |
3543 | @table @asis | |
2cd0689a TB |
3544 | @item @emph{ICV:} @var{teams-thread-limit-var} |
3545 | @item @emph{Scope:} device | |
d77de738 ML |
3546 | @item @emph{Description}: |
3547 | Specifies an upper bound for the number of threads to use by each contention | |
3548 | group created by a teams construct without explicit @code{thread_limit} | |
3549 | clause. The value of this variable shall be a positive integer. If undefined, | |
3550 | the value of 0 is used which stands for an implementation defined upper | |
3551 | limit. | |
3552 | ||
3553 | @item @emph{See also}: | |
3554 | @ref{OMP_THREAD_LIMIT}, @ref{omp_set_teams_thread_limit} | |
3555 | ||
3556 | @item @emph{Reference}: | |
3557 | @uref{https://www.openmp.org, OpenMP specification v5.1}, Section 6.24 | |
3558 | @end table | |
3559 | ||
3560 | ||
3561 | ||
3562 | @node OMP_THREAD_LIMIT | |
3563 | @section @env{OMP_THREAD_LIMIT} -- Set the maximum number of threads | |
3564 | @cindex Environment Variable | |
3565 | @table @asis | |
2cd0689a TB |
3566 | @item @emph{ICV:} @var{thread-limit-var} |
3567 | @item @emph{Scope:} data environment | |
d77de738 ML |
3568 | @item @emph{Description}: |
3569 | Specifies the number of threads to use for the whole program. The | |
3570 | value of this variable shall be a positive integer. If undefined, | |
3571 | the number of threads is not limited. | |
3572 | ||
3573 | @item @emph{See also}: | |
3574 | @ref{OMP_NUM_THREADS}, @ref{omp_get_thread_limit} | |
3575 | ||
3576 | @item @emph{Reference}: | |
3577 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.10 | |
3578 | @end table | |
3579 | ||
3580 | ||
3581 | ||
3582 | @node OMP_WAIT_POLICY | |
3583 | @section @env{OMP_WAIT_POLICY} -- How waiting threads are handled | |
3584 | @cindex Environment Variable | |
3585 | @table @asis | |
3586 | @item @emph{Description}: | |
3587 | Specifies whether waiting threads should be active or passive. If | |
3588 | the value is @code{PASSIVE}, waiting threads should not consume CPU | |
3589 | power while waiting; while the value is @code{ACTIVE} specifies that | |
3590 | they should. If undefined, threads wait actively for a short time | |
3591 | before waiting passively. | |
3592 | ||
3593 | @item @emph{See also}: | |
3594 | @ref{GOMP_SPINCOUNT} | |
3595 | ||
3596 | @item @emph{Reference}: | |
3597 | @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.8 | |
3598 | @end table | |
3599 | ||
3600 | ||
3601 | ||
3602 | @node GOMP_CPU_AFFINITY | |
3603 | @section @env{GOMP_CPU_AFFINITY} -- Bind threads to specific CPUs | |
3604 | @cindex Environment Variable | |
3605 | @table @asis | |
3606 | @item @emph{Description}: | |
3607 | Binds threads to specific CPUs. The variable should contain a space-separated | |
3608 | or comma-separated list of CPUs. This list may contain different kinds of | |
3609 | entries: either single CPU numbers in any order, a range of CPUs (M-N) | |
3610 | or a range with some stride (M-N:S). CPU numbers are zero based. For example, | |
15886c03 | 3611 | @code{GOMP_CPU_AFFINITY="0 3 1-2 4-15:2"} binds the initial thread |
d77de738 ML |
3612 | to CPU 0, the second to CPU 3, the third to CPU 1, the fourth to |
3613 | CPU 2, the fifth to CPU 4, the sixth through tenth to CPUs 6, 8, 10, 12, | |
15886c03 | 3614 | and 14 respectively and then starts assigning back from the beginning of |
d77de738 ML |
3615 | the list. @code{GOMP_CPU_AFFINITY=0} binds all threads to CPU 0. |
3616 | ||
3617 | There is no libgomp library routine to determine whether a CPU affinity | |
3618 | specification is in effect. As a workaround, language-specific library | |
3619 | functions, e.g., @code{getenv} in C or @code{GET_ENVIRONMENT_VARIABLE} in | |
3620 | Fortran, may be used to query the setting of the @code{GOMP_CPU_AFFINITY} | |
3621 | environment variable. A defined CPU affinity on startup cannot be changed | |
3622 | or disabled during the runtime of the application. | |
3623 | ||
3624 | If both @env{GOMP_CPU_AFFINITY} and @env{OMP_PROC_BIND} are set, | |
3625 | @env{OMP_PROC_BIND} has a higher precedence. If neither has been set and | |
3626 | @env{OMP_PROC_BIND} is unset, or when @env{OMP_PROC_BIND} is set to | |
15886c03 | 3627 | @code{FALSE}, the host system handles the assignment of threads to CPUs. |
d77de738 ML |
3628 | |
3629 | @item @emph{See also}: | |
3630 | @ref{OMP_PLACES}, @ref{OMP_PROC_BIND} | |
3631 | @end table | |
3632 | ||
3633 | ||
3634 | ||
3635 | @node GOMP_DEBUG | |
3636 | @section @env{GOMP_DEBUG} -- Enable debugging output | |
3637 | @cindex Environment Variable | |
3638 | @table @asis | |
3639 | @item @emph{Description}: | |
3640 | Enable debugging output. The variable should be set to @code{0} | |
3641 | (disabled, also the default if not set), or @code{1} (enabled). | |
3642 | ||
15886c03 | 3643 | If enabled, some debugging output is printed during execution. |
d77de738 ML |
3644 | This is currently not specified in more detail, and subject to change. |
3645 | @end table | |
3646 | ||
3647 | ||
3648 | ||
3649 | @node GOMP_STACKSIZE | |
3650 | @section @env{GOMP_STACKSIZE} -- Set default thread stack size | |
3651 | @cindex Environment Variable | |
3652 | @cindex Implementation specific setting | |
3653 | @table @asis | |
3654 | @item @emph{Description}: | |
3655 | Set the default thread stack size in kilobytes. This is different from | |
3656 | @code{pthread_attr_setstacksize} which gets the number of bytes as an | |
3657 | argument. If the stack size cannot be set due to system constraints, an | |
3658 | error is reported and the initial stack size is left unchanged. If undefined, | |
3659 | the stack size is system dependent. | |
3660 | ||
3661 | @item @emph{See also}: | |
3662 | @ref{OMP_STACKSIZE} | |
3663 | ||
3664 | @item @emph{Reference}: | |
3665 | @uref{https://gcc.gnu.org/ml/gcc-patches/2006-06/msg00493.html, | |
3666 | GCC Patches Mailinglist}, | |
3667 | @uref{https://gcc.gnu.org/ml/gcc-patches/2006-06/msg00496.html, | |
3668 | GCC Patches Mailinglist} | |
3669 | @end table | |
3670 | ||
3671 | ||
3672 | ||
3673 | @node GOMP_SPINCOUNT | |
3674 | @section @env{GOMP_SPINCOUNT} -- Set the busy-wait spin count | |
3675 | @cindex Environment Variable | |
3676 | @cindex Implementation specific setting | |
3677 | @table @asis | |
3678 | @item @emph{Description}: | |
3679 | Determines how long a threads waits actively with consuming CPU power | |
3680 | before waiting passively without consuming CPU power. The value may be | |
3681 | either @code{INFINITE}, @code{INFINITY} to always wait actively or an | |
3682 | integer which gives the number of spins of the busy-wait loop. The | |
3683 | integer may optionally be followed by the following suffixes acting | |
3684 | as multiplication factors: @code{k} (kilo, thousand), @code{M} (mega, | |
3685 | million), @code{G} (giga, billion), or @code{T} (tera, trillion). | |
3686 | If undefined, 0 is used when @env{OMP_WAIT_POLICY} is @code{PASSIVE}, | |
3687 | 300,000 is used when @env{OMP_WAIT_POLICY} is undefined and | |
3688 | 30 billion is used when @env{OMP_WAIT_POLICY} is @code{ACTIVE}. | |
3689 | If there are more OpenMP threads than available CPUs, 1000 and 100 | |
3690 | spins are used for @env{OMP_WAIT_POLICY} being @code{ACTIVE} or | |
3691 | undefined, respectively; unless the @env{GOMP_SPINCOUNT} is lower | |
3692 | or @env{OMP_WAIT_POLICY} is @code{PASSIVE}. | |
3693 | ||
3694 | @item @emph{See also}: | |
3695 | @ref{OMP_WAIT_POLICY} | |
3696 | @end table | |
3697 | ||
3698 | ||
3699 | ||
3700 | @node GOMP_RTEMS_THREAD_POOLS | |
3701 | @section @env{GOMP_RTEMS_THREAD_POOLS} -- Set the RTEMS specific thread pools | |
3702 | @cindex Environment Variable | |
3703 | @cindex Implementation specific setting | |
3704 | @table @asis | |
3705 | @item @emph{Description}: | |
3706 | This environment variable is only used on the RTEMS real-time operating system. | |
3707 | It determines the scheduler instance specific thread pools. The format for | |
3708 | @env{GOMP_RTEMS_THREAD_POOLS} is a list of optional | |
3709 | @code{<thread-pool-count>[$<priority>]@@<scheduler-name>} configurations | |
3710 | separated by @code{:} where: | |
3711 | @itemize @bullet | |
3712 | @item @code{<thread-pool-count>} is the thread pool count for this scheduler | |
3713 | instance. | |
3714 | @item @code{$<priority>} is an optional priority for the worker threads of a | |
3715 | thread pool according to @code{pthread_setschedparam}. In case a priority | |
15886c03 | 3716 | value is omitted, then a worker thread inherits the priority of the OpenMP |
d77de738 ML |
3717 | primary thread that created it. The priority of the worker thread is not |
3718 | changed after creation, even if a new OpenMP primary thread using the worker has | |
3719 | a different priority. | |
3720 | @item @code{@@<scheduler-name>} is the scheduler instance name according to the | |
3721 | RTEMS application configuration. | |
3722 | @end itemize | |
3723 | In case no thread pool configuration is specified for a scheduler instance, | |
15886c03 | 3724 | then each OpenMP primary thread of this scheduler instance uses its own |
d77de738 ML |
3725 | dynamically allocated thread pool. To limit the worker thread count of the |
3726 | thread pools, each OpenMP primary thread must call @code{omp_set_num_threads}. | |
3727 | @item @emph{Example}: | |
3728 | Lets suppose we have three scheduler instances @code{IO}, @code{WRK0}, and | |
3729 | @code{WRK1} with @env{GOMP_RTEMS_THREAD_POOLS} set to | |
3730 | @code{"1@@WRK0:3$4@@WRK1"}. Then there are no thread pool restrictions for | |
3731 | scheduler instance @code{IO}. In the scheduler instance @code{WRK0} there is | |
3732 | one thread pool available. Since no priority is specified for this scheduler | |
3733 | instance, the worker thread inherits the priority of the OpenMP primary thread | |
3734 | that created it. In the scheduler instance @code{WRK1} there are three thread | |
3735 | pools available and their worker threads run at priority four. | |
3736 | @end table | |
3737 | ||
3738 | ||
3739 | ||
3740 | @c --------------------------------------------------------------------- | |
3741 | @c Enabling OpenACC | |
3742 | @c --------------------------------------------------------------------- | |
3743 | ||
3744 | @node Enabling OpenACC | |
3745 | @chapter Enabling OpenACC | |
3746 | ||
3747 | To activate the OpenACC extensions for C/C++ and Fortran, the compile-time | |
3748 | flag @option{-fopenacc} must be specified. This enables the OpenACC directive | |
643a5223 TB |
3749 | @samp{#pragma acc} in C/C++ and, in Fortran, the @samp{!$acc} sentinel in free |
3750 | source form and the @samp{c$acc}, @samp{*$acc} and @samp{!$acc} sentinels in | |
3751 | fixed source form. The flag also arranges for automatic linking of the OpenACC | |
3752 | runtime library (@ref{OpenACC Runtime Library Routines}). | |
d77de738 ML |
3753 | |
3754 | See @uref{https://gcc.gnu.org/wiki/OpenACC} for more information. | |
3755 | ||
3756 | A complete description of all OpenACC directives accepted may be found in | |
3757 | the @uref{https://www.openacc.org, OpenACC} Application Programming | |
3758 | Interface manual, version 2.6. | |
3759 | ||
3760 | ||
3761 | ||
3762 | @c --------------------------------------------------------------------- | |
3763 | @c OpenACC Runtime Library Routines | |
3764 | @c --------------------------------------------------------------------- | |
3765 | ||
3766 | @node OpenACC Runtime Library Routines | |
3767 | @chapter OpenACC Runtime Library Routines | |
3768 | ||
3769 | The runtime routines described here are defined by section 3 of the OpenACC | |
3770 | specifications in version 2.6. | |
3771 | They have C linkage, and do not throw exceptions. | |
3772 | Generally, they are available only for the host, with the exception of | |
3773 | @code{acc_on_device}, which is available for both the host and the | |
3774 | acceleration device. | |
3775 | ||
3776 | @menu | |
3777 | * acc_get_num_devices:: Get number of devices for the given device | |
3778 | type. | |
3779 | * acc_set_device_type:: Set type of device accelerator to use. | |
3780 | * acc_get_device_type:: Get type of device accelerator to be used. | |
3781 | * acc_set_device_num:: Set device number to use. | |
3782 | * acc_get_device_num:: Get device number to be used. | |
3783 | * acc_get_property:: Get device property. | |
3784 | * acc_async_test:: Tests for completion of a specific asynchronous | |
3785 | operation. | |
3786 | * acc_async_test_all:: Tests for completion of all asynchronous | |
3787 | operations. | |
3788 | * acc_wait:: Wait for completion of a specific asynchronous | |
3789 | operation. | |
3790 | * acc_wait_all:: Waits for completion of all asynchronous | |
3791 | operations. | |
3792 | * acc_wait_all_async:: Wait for completion of all asynchronous | |
3793 | operations. | |
3794 | * acc_wait_async:: Wait for completion of asynchronous operations. | |
3795 | * acc_init:: Initialize runtime for a specific device type. | |
3796 | * acc_shutdown:: Shuts down the runtime for a specific device | |
3797 | type. | |
3798 | * acc_on_device:: Whether executing on a particular device | |
3799 | * acc_malloc:: Allocate device memory. | |
3800 | * acc_free:: Free device memory. | |
3801 | * acc_copyin:: Allocate device memory and copy host memory to | |
3802 | it. | |
3803 | * acc_present_or_copyin:: If the data is not present on the device, | |
3804 | allocate device memory and copy from host | |
3805 | memory. | |
3806 | * acc_create:: Allocate device memory and map it to host | |
3807 | memory. | |
3808 | * acc_present_or_create:: If the data is not present on the device, | |
3809 | allocate device memory and map it to host | |
3810 | memory. | |
3811 | * acc_copyout:: Copy device memory to host memory. | |
3812 | * acc_delete:: Free device memory. | |
3813 | * acc_update_device:: Update device memory from mapped host memory. | |
3814 | * acc_update_self:: Update host memory from mapped device memory. | |
3815 | * acc_map_data:: Map previously allocated device memory to host | |
3816 | memory. | |
3817 | * acc_unmap_data:: Unmap device memory from host memory. | |
3818 | * acc_deviceptr:: Get device pointer associated with specific | |
3819 | host address. | |
3820 | * acc_hostptr:: Get host pointer associated with specific | |
3821 | device address. | |
3822 | * acc_is_present:: Indicate whether host variable / array is | |
3823 | present on device. | |
3824 | * acc_memcpy_to_device:: Copy host memory to device memory. | |
3825 | * acc_memcpy_from_device:: Copy device memory to host memory. | |
3826 | * acc_attach:: Let device pointer point to device-pointer target. | |
3827 | * acc_detach:: Let device pointer point to host-pointer target. | |
3828 | ||
3829 | API routines for target platforms. | |
3830 | ||
3831 | * acc_get_current_cuda_device:: Get CUDA device handle. | |
3832 | * acc_get_current_cuda_context::Get CUDA context handle. | |
3833 | * acc_get_cuda_stream:: Get CUDA stream handle. | |
3834 | * acc_set_cuda_stream:: Set CUDA stream handle. | |
3835 | ||
3836 | API routines for the OpenACC Profiling Interface. | |
3837 | ||
3838 | * acc_prof_register:: Register callbacks. | |
3839 | * acc_prof_unregister:: Unregister callbacks. | |
3840 | * acc_prof_lookup:: Obtain inquiry functions. | |
3841 | * acc_register_library:: Library registration. | |
3842 | @end menu | |
3843 | ||
3844 | ||
3845 | ||
3846 | @node acc_get_num_devices | |
3847 | @section @code{acc_get_num_devices} -- Get number of devices for given device type | |
3848 | @table @asis | |
3849 | @item @emph{Description} | |
3850 | This function returns a value indicating the number of devices available | |
3851 | for the device type specified in @var{devicetype}. | |
3852 | ||
3853 | @item @emph{C/C++}: | |
3854 | @multitable @columnfractions .20 .80 | |
3855 | @item @emph{Prototype}: @tab @code{int acc_get_num_devices(acc_device_t devicetype);} | |
3856 | @end multitable | |
3857 | ||
3858 | @item @emph{Fortran}: | |
3859 | @multitable @columnfractions .20 .80 | |
3860 | @item @emph{Interface}: @tab @code{integer function acc_get_num_devices(devicetype)} | |
3861 | @item @tab @code{integer(kind=acc_device_kind) devicetype} | |
3862 | @end multitable | |
3863 | ||
3864 | @item @emph{Reference}: | |
3865 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
3866 | 3.2.1. | |
3867 | @end table | |
3868 | ||
3869 | ||
3870 | ||
3871 | @node acc_set_device_type | |
3872 | @section @code{acc_set_device_type} -- Set type of device accelerator to use. | |
3873 | @table @asis | |
3874 | @item @emph{Description} | |
3875 | This function indicates to the runtime library which device type, specified | |
3876 | in @var{devicetype}, to use when executing a parallel or kernels region. | |
3877 | ||
3878 | @item @emph{C/C++}: | |
3879 | @multitable @columnfractions .20 .80 | |
3880 | @item @emph{Prototype}: @tab @code{acc_set_device_type(acc_device_t devicetype);} | |
3881 | @end multitable | |
3882 | ||
3883 | @item @emph{Fortran}: | |
3884 | @multitable @columnfractions .20 .80 | |
3885 | @item @emph{Interface}: @tab @code{subroutine acc_set_device_type(devicetype)} | |
3886 | @item @tab @code{integer(kind=acc_device_kind) devicetype} | |
3887 | @end multitable | |
3888 | ||
3889 | @item @emph{Reference}: | |
3890 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
3891 | 3.2.2. | |
3892 | @end table | |
3893 | ||
3894 | ||
3895 | ||
3896 | @node acc_get_device_type | |
3897 | @section @code{acc_get_device_type} -- Get type of device accelerator to be used. | |
3898 | @table @asis | |
3899 | @item @emph{Description} | |
3900 | This function returns what device type will be used when executing a | |
3901 | parallel or kernels region. | |
3902 | ||
3903 | This function returns @code{acc_device_none} if | |
3904 | @code{acc_get_device_type} is called from | |
3905 | @code{acc_ev_device_init_start}, @code{acc_ev_device_init_end} | |
3906 | callbacks of the OpenACC Profiling Interface (@ref{OpenACC Profiling | |
3907 | Interface}), that is, if the device is currently being initialized. | |
3908 | ||
3909 | @item @emph{C/C++}: | |
3910 | @multitable @columnfractions .20 .80 | |
3911 | @item @emph{Prototype}: @tab @code{acc_device_t acc_get_device_type(void);} | |
3912 | @end multitable | |
3913 | ||
3914 | @item @emph{Fortran}: | |
3915 | @multitable @columnfractions .20 .80 | |
3916 | @item @emph{Interface}: @tab @code{function acc_get_device_type(void)} | |
3917 | @item @tab @code{integer(kind=acc_device_kind) acc_get_device_type} | |
3918 | @end multitable | |
3919 | ||
3920 | @item @emph{Reference}: | |
3921 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
3922 | 3.2.3. | |
3923 | @end table | |
3924 | ||
3925 | ||
3926 | ||
3927 | @node acc_set_device_num | |
3928 | @section @code{acc_set_device_num} -- Set device number to use. | |
3929 | @table @asis | |
3930 | @item @emph{Description} | |
3931 | This function will indicate to the runtime which device number, | |
3932 | specified by @var{devicenum}, associated with the specified device | |
3933 | type @var{devicetype}. | |
3934 | ||
3935 | @item @emph{C/C++}: | |
3936 | @multitable @columnfractions .20 .80 | |
3937 | @item @emph{Prototype}: @tab @code{acc_set_device_num(int devicenum, acc_device_t devicetype);} | |
3938 | @end multitable | |
3939 | ||
3940 | @item @emph{Fortran}: | |
3941 | @multitable @columnfractions .20 .80 | |
3942 | @item @emph{Interface}: @tab @code{subroutine acc_set_device_num(devicenum, devicetype)} | |
3943 | @item @tab @code{integer devicenum} | |
3944 | @item @tab @code{integer(kind=acc_device_kind) devicetype} | |
3945 | @end multitable | |
3946 | ||
3947 | @item @emph{Reference}: | |
3948 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
3949 | 3.2.4. | |
3950 | @end table | |
3951 | ||
3952 | ||
3953 | ||
3954 | @node acc_get_device_num | |
3955 | @section @code{acc_get_device_num} -- Get device number to be used. | |
3956 | @table @asis | |
3957 | @item @emph{Description} | |
3958 | This function returns which device number associated with the specified device | |
3959 | type @var{devicetype}, will be used when executing a parallel or kernels | |
3960 | region. | |
3961 | ||
3962 | @item @emph{C/C++}: | |
3963 | @multitable @columnfractions .20 .80 | |
3964 | @item @emph{Prototype}: @tab @code{int acc_get_device_num(acc_device_t devicetype);} | |
3965 | @end multitable | |
3966 | ||
3967 | @item @emph{Fortran}: | |
3968 | @multitable @columnfractions .20 .80 | |
3969 | @item @emph{Interface}: @tab @code{function acc_get_device_num(devicetype)} | |
3970 | @item @tab @code{integer(kind=acc_device_kind) devicetype} | |
3971 | @item @tab @code{integer acc_get_device_num} | |
3972 | @end multitable | |
3973 | ||
3974 | @item @emph{Reference}: | |
3975 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
3976 | 3.2.5. | |
3977 | @end table | |
3978 | ||
3979 | ||
3980 | ||
3981 | @node acc_get_property | |
3982 | @section @code{acc_get_property} -- Get device property. | |
3983 | @cindex acc_get_property | |
3984 | @cindex acc_get_property_string | |
3985 | @table @asis | |
3986 | @item @emph{Description} | |
3987 | These routines return the value of the specified @var{property} for the | |
3988 | device being queried according to @var{devicenum} and @var{devicetype}. | |
3989 | Integer-valued and string-valued properties are returned by | |
3990 | @code{acc_get_property} and @code{acc_get_property_string} respectively. | |
3991 | The Fortran @code{acc_get_property_string} subroutine returns the string | |
3992 | retrieved in its fourth argument while the remaining entry points are | |
3993 | functions, which pass the return value as their result. | |
3994 | ||
3995 | Note for Fortran, only: the OpenACC technical committee corrected and, hence, | |
3996 | modified the interface introduced in OpenACC 2.6. The kind-value parameter | |
3997 | @code{acc_device_property} has been renamed to @code{acc_device_property_kind} | |
3998 | for consistency and the return type of the @code{acc_get_property} function is | |
3999 | now a @code{c_size_t} integer instead of a @code{acc_device_property} integer. | |
15886c03 | 4000 | The parameter @code{acc_device_property} is still provided, |
d77de738 ML |
4001 | but might be removed in a future version of GCC. |
4002 | ||
4003 | @item @emph{C/C++}: | |
4004 | @multitable @columnfractions .20 .80 | |
4005 | @item @emph{Prototype}: @tab @code{size_t acc_get_property(int devicenum, acc_device_t devicetype, acc_device_property_t property);} | |
4006 | @item @emph{Prototype}: @tab @code{const char *acc_get_property_string(int devicenum, acc_device_t devicetype, acc_device_property_t property);} | |
4007 | @end multitable | |
4008 | ||
4009 | @item @emph{Fortran}: | |
4010 | @multitable @columnfractions .20 .80 | |
4011 | @item @emph{Interface}: @tab @code{function acc_get_property(devicenum, devicetype, property)} | |
4012 | @item @emph{Interface}: @tab @code{subroutine acc_get_property_string(devicenum, devicetype, property, string)} | |
4013 | @item @tab @code{use ISO_C_Binding, only: c_size_t} | |
4014 | @item @tab @code{integer devicenum} | |
4015 | @item @tab @code{integer(kind=acc_device_kind) devicetype} | |
4016 | @item @tab @code{integer(kind=acc_device_property_kind) property} | |
4017 | @item @tab @code{integer(kind=c_size_t) acc_get_property} | |
4018 | @item @tab @code{character(*) string} | |
4019 | @end multitable | |
4020 | ||
4021 | @item @emph{Reference}: | |
4022 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4023 | 3.2.6. | |
4024 | @end table | |
4025 | ||
4026 | ||
4027 | ||
4028 | @node acc_async_test | |
4029 | @section @code{acc_async_test} -- Test for completion of a specific asynchronous operation. | |
4030 | @table @asis | |
4031 | @item @emph{Description} | |
4032 | This function tests for completion of the asynchronous operation specified | |
15886c03 TB |
4033 | in @var{arg}. In C/C++, a non-zero value is returned to indicate |
4034 | the specified asynchronous operation has completed while Fortran returns | |
4035 | @code{true}. If the asynchronous operation has not completed, C/C++ returns | |
4036 | zero and Fortran returns @code{false}. | |
d77de738 ML |
4037 | |
4038 | @item @emph{C/C++}: | |
4039 | @multitable @columnfractions .20 .80 | |
4040 | @item @emph{Prototype}: @tab @code{int acc_async_test(int arg);} | |
4041 | @end multitable | |
4042 | ||
4043 | @item @emph{Fortran}: | |
4044 | @multitable @columnfractions .20 .80 | |
4045 | @item @emph{Interface}: @tab @code{function acc_async_test(arg)} | |
4046 | @item @tab @code{integer(kind=acc_handle_kind) arg} | |
4047 | @item @tab @code{logical acc_async_test} | |
4048 | @end multitable | |
4049 | ||
4050 | @item @emph{Reference}: | |
4051 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4052 | 3.2.9. | |
4053 | @end table | |
4054 | ||
4055 | ||
4056 | ||
4057 | @node acc_async_test_all | |
4058 | @section @code{acc_async_test_all} -- Tests for completion of all asynchronous operations. | |
4059 | @table @asis | |
4060 | @item @emph{Description} | |
4061 | This function tests for completion of all asynchronous operations. | |
15886c03 TB |
4062 | In C/C++, a non-zero value is returned to indicate all asynchronous |
4063 | operations have completed while Fortran returns @code{true}. If | |
4064 | any asynchronous operation has not completed, C/C++ returns zero and | |
4065 | Fortran returns @code{false}. | |
d77de738 ML |
4066 | |
4067 | @item @emph{C/C++}: | |
4068 | @multitable @columnfractions .20 .80 | |
4069 | @item @emph{Prototype}: @tab @code{int acc_async_test_all(void);} | |
4070 | @end multitable | |
4071 | ||
4072 | @item @emph{Fortran}: | |
4073 | @multitable @columnfractions .20 .80 | |
4074 | @item @emph{Interface}: @tab @code{function acc_async_test()} | |
4075 | @item @tab @code{logical acc_get_device_num} | |
4076 | @end multitable | |
4077 | ||
4078 | @item @emph{Reference}: | |
4079 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4080 | 3.2.10. | |
4081 | @end table | |
4082 | ||
4083 | ||
4084 | ||
4085 | @node acc_wait | |
4086 | @section @code{acc_wait} -- Wait for completion of a specific asynchronous operation. | |
4087 | @table @asis | |
4088 | @item @emph{Description} | |
4089 | This function waits for completion of the asynchronous operation | |
4090 | specified in @var{arg}. | |
4091 | ||
4092 | @item @emph{C/C++}: | |
4093 | @multitable @columnfractions .20 .80 | |
4094 | @item @emph{Prototype}: @tab @code{acc_wait(arg);} | |
4095 | @item @emph{Prototype (OpenACC 1.0 compatibility)}: @tab @code{acc_async_wait(arg);} | |
4096 | @end multitable | |
4097 | ||
4098 | @item @emph{Fortran}: | |
4099 | @multitable @columnfractions .20 .80 | |
4100 | @item @emph{Interface}: @tab @code{subroutine acc_wait(arg)} | |
4101 | @item @tab @code{integer(acc_handle_kind) arg} | |
4102 | @item @emph{Interface (OpenACC 1.0 compatibility)}: @tab @code{subroutine acc_async_wait(arg)} | |
4103 | @item @tab @code{integer(acc_handle_kind) arg} | |
4104 | @end multitable | |
4105 | ||
4106 | @item @emph{Reference}: | |
4107 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4108 | 3.2.11. | |
4109 | @end table | |
4110 | ||
4111 | ||
4112 | ||
4113 | @node acc_wait_all | |
4114 | @section @code{acc_wait_all} -- Waits for completion of all asynchronous operations. | |
4115 | @table @asis | |
4116 | @item @emph{Description} | |
4117 | This function waits for the completion of all asynchronous operations. | |
4118 | ||
4119 | @item @emph{C/C++}: | |
4120 | @multitable @columnfractions .20 .80 | |
4121 | @item @emph{Prototype}: @tab @code{acc_wait_all(void);} | |
4122 | @item @emph{Prototype (OpenACC 1.0 compatibility)}: @tab @code{acc_async_wait_all(void);} | |
4123 | @end multitable | |
4124 | ||
4125 | @item @emph{Fortran}: | |
4126 | @multitable @columnfractions .20 .80 | |
4127 | @item @emph{Interface}: @tab @code{subroutine acc_wait_all()} | |
4128 | @item @emph{Interface (OpenACC 1.0 compatibility)}: @tab @code{subroutine acc_async_wait_all()} | |
4129 | @end multitable | |
4130 | ||
4131 | @item @emph{Reference}: | |
4132 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4133 | 3.2.13. | |
4134 | @end table | |
4135 | ||
4136 | ||
4137 | ||
4138 | @node acc_wait_all_async | |
4139 | @section @code{acc_wait_all_async} -- Wait for completion of all asynchronous operations. | |
4140 | @table @asis | |
4141 | @item @emph{Description} | |
4142 | This function enqueues a wait operation on the queue @var{async} for any | |
4143 | and all asynchronous operations that have been previously enqueued on | |
4144 | any queue. | |
4145 | ||
4146 | @item @emph{C/C++}: | |
4147 | @multitable @columnfractions .20 .80 | |
4148 | @item @emph{Prototype}: @tab @code{acc_wait_all_async(int async);} | |
4149 | @end multitable | |
4150 | ||
4151 | @item @emph{Fortran}: | |
4152 | @multitable @columnfractions .20 .80 | |
4153 | @item @emph{Interface}: @tab @code{subroutine acc_wait_all_async(async)} | |
4154 | @item @tab @code{integer(acc_handle_kind) async} | |
4155 | @end multitable | |
4156 | ||
4157 | @item @emph{Reference}: | |
4158 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4159 | 3.2.14. | |
4160 | @end table | |
4161 | ||
4162 | ||
4163 | ||
4164 | @node acc_wait_async | |
4165 | @section @code{acc_wait_async} -- Wait for completion of asynchronous operations. | |
4166 | @table @asis | |
4167 | @item @emph{Description} | |
4168 | This function enqueues a wait operation on queue @var{async} for any and all | |
4169 | asynchronous operations enqueued on queue @var{arg}. | |
4170 | ||
4171 | @item @emph{C/C++}: | |
4172 | @multitable @columnfractions .20 .80 | |
4173 | @item @emph{Prototype}: @tab @code{acc_wait_async(int arg, int async);} | |
4174 | @end multitable | |
4175 | ||
4176 | @item @emph{Fortran}: | |
4177 | @multitable @columnfractions .20 .80 | |
4178 | @item @emph{Interface}: @tab @code{subroutine acc_wait_async(arg, async)} | |
4179 | @item @tab @code{integer(acc_handle_kind) arg, async} | |
4180 | @end multitable | |
4181 | ||
4182 | @item @emph{Reference}: | |
4183 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4184 | 3.2.12. | |
4185 | @end table | |
4186 | ||
4187 | ||
4188 | ||
4189 | @node acc_init | |
4190 | @section @code{acc_init} -- Initialize runtime for a specific device type. | |
4191 | @table @asis | |
4192 | @item @emph{Description} | |
4193 | This function initializes the runtime for the device type specified in | |
4194 | @var{devicetype}. | |
4195 | ||
4196 | @item @emph{C/C++}: | |
4197 | @multitable @columnfractions .20 .80 | |
4198 | @item @emph{Prototype}: @tab @code{acc_init(acc_device_t devicetype);} | |
4199 | @end multitable | |
4200 | ||
4201 | @item @emph{Fortran}: | |
4202 | @multitable @columnfractions .20 .80 | |
4203 | @item @emph{Interface}: @tab @code{subroutine acc_init(devicetype)} | |
4204 | @item @tab @code{integer(acc_device_kind) devicetype} | |
4205 | @end multitable | |
4206 | ||
4207 | @item @emph{Reference}: | |
4208 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4209 | 3.2.7. | |
4210 | @end table | |
4211 | ||
4212 | ||
4213 | ||
4214 | @node acc_shutdown | |
4215 | @section @code{acc_shutdown} -- Shuts down the runtime for a specific device type. | |
4216 | @table @asis | |
4217 | @item @emph{Description} | |
4218 | This function shuts down the runtime for the device type specified in | |
4219 | @var{devicetype}. | |
4220 | ||
4221 | @item @emph{C/C++}: | |
4222 | @multitable @columnfractions .20 .80 | |
4223 | @item @emph{Prototype}: @tab @code{acc_shutdown(acc_device_t devicetype);} | |
4224 | @end multitable | |
4225 | ||
4226 | @item @emph{Fortran}: | |
4227 | @multitable @columnfractions .20 .80 | |
4228 | @item @emph{Interface}: @tab @code{subroutine acc_shutdown(devicetype)} | |
4229 | @item @tab @code{integer(acc_device_kind) devicetype} | |
4230 | @end multitable | |
4231 | ||
4232 | @item @emph{Reference}: | |
4233 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4234 | 3.2.8. | |
4235 | @end table | |
4236 | ||
4237 | ||
4238 | ||
4239 | @node acc_on_device | |
4240 | @section @code{acc_on_device} -- Whether executing on a particular device | |
4241 | @table @asis | |
4242 | @item @emph{Description}: | |
4243 | This function returns whether the program is executing on a particular | |
4244 | device specified in @var{devicetype}. In C/C++ a non-zero value is | |
4245 | returned to indicate the device is executing on the specified device type. | |
15886c03 TB |
4246 | In Fortran, @code{true} is returned. If the program is not executing |
4247 | on the specified device type C/C++ returns zero, while Fortran | |
4248 | returns @code{false}. | |
d77de738 ML |
4249 | |
4250 | @item @emph{C/C++}: | |
4251 | @multitable @columnfractions .20 .80 | |
4252 | @item @emph{Prototype}: @tab @code{acc_on_device(acc_device_t devicetype);} | |
4253 | @end multitable | |
4254 | ||
4255 | @item @emph{Fortran}: | |
4256 | @multitable @columnfractions .20 .80 | |
4257 | @item @emph{Interface}: @tab @code{function acc_on_device(devicetype)} | |
4258 | @item @tab @code{integer(acc_device_kind) devicetype} | |
4259 | @item @tab @code{logical acc_on_device} | |
4260 | @end multitable | |
4261 | ||
4262 | ||
4263 | @item @emph{Reference}: | |
4264 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4265 | 3.2.17. | |
4266 | @end table | |
4267 | ||
4268 | ||
4269 | ||
4270 | @node acc_malloc | |
4271 | @section @code{acc_malloc} -- Allocate device memory. | |
4272 | @table @asis | |
4273 | @item @emph{Description} | |
4274 | This function allocates @var{len} bytes of device memory. It returns | |
4275 | the device address of the allocated memory. | |
4276 | ||
4277 | @item @emph{C/C++}: | |
4278 | @multitable @columnfractions .20 .80 | |
4279 | @item @emph{Prototype}: @tab @code{d_void* acc_malloc(size_t len);} | |
4280 | @end multitable | |
4281 | ||
4282 | @item @emph{Reference}: | |
4283 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4284 | 3.2.18. | |
4285 | @end table | |
4286 | ||
4287 | ||
4288 | ||
4289 | @node acc_free | |
4290 | @section @code{acc_free} -- Free device memory. | |
4291 | @table @asis | |
4292 | @item @emph{Description} | |
4293 | Free previously allocated device memory at the device address @code{a}. | |
4294 | ||
4295 | @item @emph{C/C++}: | |
4296 | @multitable @columnfractions .20 .80 | |
4297 | @item @emph{Prototype}: @tab @code{acc_free(d_void *a);} | |
4298 | @end multitable | |
4299 | ||
4300 | @item @emph{Reference}: | |
4301 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4302 | 3.2.19. | |
4303 | @end table | |
4304 | ||
4305 | ||
4306 | ||
4307 | @node acc_copyin | |
4308 | @section @code{acc_copyin} -- Allocate device memory and copy host memory to it. | |
4309 | @table @asis | |
4310 | @item @emph{Description} | |
4311 | In C/C++, this function allocates @var{len} bytes of device memory | |
4312 | and maps it to the specified host address in @var{a}. The device | |
4313 | address of the newly allocated device memory is returned. | |
4314 | ||
4315 | In Fortran, two (2) forms are supported. In the first form, @var{a} specifies | |
4316 | a contiguous array section. The second form @var{a} specifies a | |
4317 | variable or array element and @var{len} specifies the length in bytes. | |
4318 | ||
4319 | @item @emph{C/C++}: | |
4320 | @multitable @columnfractions .20 .80 | |
4321 | @item @emph{Prototype}: @tab @code{void *acc_copyin(h_void *a, size_t len);} | |
4322 | @item @emph{Prototype}: @tab @code{void *acc_copyin_async(h_void *a, size_t len, int async);} | |
4323 | @end multitable | |
4324 | ||
4325 | @item @emph{Fortran}: | |
4326 | @multitable @columnfractions .20 .80 | |
4327 | @item @emph{Interface}: @tab @code{subroutine acc_copyin(a)} | |
4328 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4329 | @item @emph{Interface}: @tab @code{subroutine acc_copyin(a, len)} | |
4330 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4331 | @item @tab @code{integer len} | |
4332 | @item @emph{Interface}: @tab @code{subroutine acc_copyin_async(a, async)} | |
4333 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4334 | @item @tab @code{integer(acc_handle_kind) :: async} | |
4335 | @item @emph{Interface}: @tab @code{subroutine acc_copyin_async(a, len, async)} | |
4336 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4337 | @item @tab @code{integer len} | |
4338 | @item @tab @code{integer(acc_handle_kind) :: async} | |
4339 | @end multitable | |
4340 | ||
4341 | @item @emph{Reference}: | |
4342 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4343 | 3.2.20. | |
4344 | @end table | |
4345 | ||
4346 | ||
4347 | ||
4348 | @node acc_present_or_copyin | |
4349 | @section @code{acc_present_or_copyin} -- If the data is not present on the device, allocate device memory and copy from host memory. | |
4350 | @table @asis | |
4351 | @item @emph{Description} | |
4352 | This function tests if the host data specified by @var{a} and of length | |
15886c03 TB |
4353 | @var{len} is present or not. If it is not present, device memory |
4354 | is allocated and the host memory copied. The device address of | |
d77de738 ML |
4355 | the newly allocated device memory is returned. |
4356 | ||
4357 | In Fortran, two (2) forms are supported. In the first form, @var{a} specifies | |
4358 | a contiguous array section. The second form @var{a} specifies a variable or | |
4359 | array element and @var{len} specifies the length in bytes. | |
4360 | ||
4361 | Note that @code{acc_present_or_copyin} and @code{acc_pcopyin} exist for | |
4362 | backward compatibility with OpenACC 2.0; use @ref{acc_copyin} instead. | |
4363 | ||
4364 | @item @emph{C/C++}: | |
4365 | @multitable @columnfractions .20 .80 | |
4366 | @item @emph{Prototype}: @tab @code{void *acc_present_or_copyin(h_void *a, size_t len);} | |
4367 | @item @emph{Prototype}: @tab @code{void *acc_pcopyin(h_void *a, size_t len);} | |
4368 | @end multitable | |
4369 | ||
4370 | @item @emph{Fortran}: | |
4371 | @multitable @columnfractions .20 .80 | |
4372 | @item @emph{Interface}: @tab @code{subroutine acc_present_or_copyin(a)} | |
4373 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4374 | @item @emph{Interface}: @tab @code{subroutine acc_present_or_copyin(a, len)} | |
4375 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4376 | @item @tab @code{integer len} | |
4377 | @item @emph{Interface}: @tab @code{subroutine acc_pcopyin(a)} | |
4378 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4379 | @item @emph{Interface}: @tab @code{subroutine acc_pcopyin(a, len)} | |
4380 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4381 | @item @tab @code{integer len} | |
4382 | @end multitable | |
4383 | ||
4384 | @item @emph{Reference}: | |
4385 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4386 | 3.2.20. | |
4387 | @end table | |
4388 | ||
4389 | ||
4390 | ||
4391 | @node acc_create | |
4392 | @section @code{acc_create} -- Allocate device memory and map it to host memory. | |
4393 | @table @asis | |
4394 | @item @emph{Description} | |
4395 | This function allocates device memory and maps it to host memory specified | |
4396 | by the host address @var{a} with a length of @var{len} bytes. In C/C++, | |
4397 | the function returns the device address of the allocated device memory. | |
4398 | ||
4399 | In Fortran, two (2) forms are supported. In the first form, @var{a} specifies | |
4400 | a contiguous array section. The second form @var{a} specifies a variable or | |
4401 | array element and @var{len} specifies the length in bytes. | |
4402 | ||
4403 | @item @emph{C/C++}: | |
4404 | @multitable @columnfractions .20 .80 | |
4405 | @item @emph{Prototype}: @tab @code{void *acc_create(h_void *a, size_t len);} | |
4406 | @item @emph{Prototype}: @tab @code{void *acc_create_async(h_void *a, size_t len, int async);} | |
4407 | @end multitable | |
4408 | ||
4409 | @item @emph{Fortran}: | |
4410 | @multitable @columnfractions .20 .80 | |
4411 | @item @emph{Interface}: @tab @code{subroutine acc_create(a)} | |
4412 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4413 | @item @emph{Interface}: @tab @code{subroutine acc_create(a, len)} | |
4414 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4415 | @item @tab @code{integer len} | |
4416 | @item @emph{Interface}: @tab @code{subroutine acc_create_async(a, async)} | |
4417 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4418 | @item @tab @code{integer(acc_handle_kind) :: async} | |
4419 | @item @emph{Interface}: @tab @code{subroutine acc_create_async(a, len, async)} | |
4420 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4421 | @item @tab @code{integer len} | |
4422 | @item @tab @code{integer(acc_handle_kind) :: async} | |
4423 | @end multitable | |
4424 | ||
4425 | @item @emph{Reference}: | |
4426 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4427 | 3.2.21. | |
4428 | @end table | |
4429 | ||
4430 | ||
4431 | ||
4432 | @node acc_present_or_create | |
4433 | @section @code{acc_present_or_create} -- If the data is not present on the device, allocate device memory and map it to host memory. | |
4434 | @table @asis | |
4435 | @item @emph{Description} | |
4436 | This function tests if the host data specified by @var{a} and of length | |
15886c03 TB |
4437 | @var{len} is present or not. If it is not present, device memory |
4438 | is allocated and mapped to host memory. In C/C++, the device address | |
d77de738 ML |
4439 | of the newly allocated device memory is returned. |
4440 | ||
4441 | In Fortran, two (2) forms are supported. In the first form, @var{a} specifies | |
4442 | a contiguous array section. The second form @var{a} specifies a variable or | |
4443 | array element and @var{len} specifies the length in bytes. | |
4444 | ||
4445 | Note that @code{acc_present_or_create} and @code{acc_pcreate} exist for | |
4446 | backward compatibility with OpenACC 2.0; use @ref{acc_create} instead. | |
4447 | ||
4448 | @item @emph{C/C++}: | |
4449 | @multitable @columnfractions .20 .80 | |
4450 | @item @emph{Prototype}: @tab @code{void *acc_present_or_create(h_void *a, size_t len)} | |
4451 | @item @emph{Prototype}: @tab @code{void *acc_pcreate(h_void *a, size_t len)} | |
4452 | @end multitable | |
4453 | ||
4454 | @item @emph{Fortran}: | |
4455 | @multitable @columnfractions .20 .80 | |
4456 | @item @emph{Interface}: @tab @code{subroutine acc_present_or_create(a)} | |
4457 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4458 | @item @emph{Interface}: @tab @code{subroutine acc_present_or_create(a, len)} | |
4459 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4460 | @item @tab @code{integer len} | |
4461 | @item @emph{Interface}: @tab @code{subroutine acc_pcreate(a)} | |
4462 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4463 | @item @emph{Interface}: @tab @code{subroutine acc_pcreate(a, len)} | |
4464 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4465 | @item @tab @code{integer len} | |
4466 | @end multitable | |
4467 | ||
4468 | @item @emph{Reference}: | |
4469 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4470 | 3.2.21. | |
4471 | @end table | |
4472 | ||
4473 | ||
4474 | ||
4475 | @node acc_copyout | |
4476 | @section @code{acc_copyout} -- Copy device memory to host memory. | |
4477 | @table @asis | |
4478 | @item @emph{Description} | |
4479 | This function copies mapped device memory to host memory which is specified | |
4480 | by host address @var{a} for a length @var{len} bytes in C/C++. | |
4481 | ||
4482 | In Fortran, two (2) forms are supported. In the first form, @var{a} specifies | |
4483 | a contiguous array section. The second form @var{a} specifies a variable or | |
4484 | array element and @var{len} specifies the length in bytes. | |
4485 | ||
4486 | @item @emph{C/C++}: | |
4487 | @multitable @columnfractions .20 .80 | |
4488 | @item @emph{Prototype}: @tab @code{acc_copyout(h_void *a, size_t len);} | |
4489 | @item @emph{Prototype}: @tab @code{acc_copyout_async(h_void *a, size_t len, int async);} | |
4490 | @item @emph{Prototype}: @tab @code{acc_copyout_finalize(h_void *a, size_t len);} | |
4491 | @item @emph{Prototype}: @tab @code{acc_copyout_finalize_async(h_void *a, size_t len, int async);} | |
4492 | @end multitable | |
4493 | ||
4494 | @item @emph{Fortran}: | |
4495 | @multitable @columnfractions .20 .80 | |
4496 | @item @emph{Interface}: @tab @code{subroutine acc_copyout(a)} | |
4497 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4498 | @item @emph{Interface}: @tab @code{subroutine acc_copyout(a, len)} | |
4499 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4500 | @item @tab @code{integer len} | |
4501 | @item @emph{Interface}: @tab @code{subroutine acc_copyout_async(a, async)} | |
4502 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4503 | @item @tab @code{integer(acc_handle_kind) :: async} | |
4504 | @item @emph{Interface}: @tab @code{subroutine acc_copyout_async(a, len, async)} | |
4505 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4506 | @item @tab @code{integer len} | |
4507 | @item @tab @code{integer(acc_handle_kind) :: async} | |
4508 | @item @emph{Interface}: @tab @code{subroutine acc_copyout_finalize(a)} | |
4509 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4510 | @item @emph{Interface}: @tab @code{subroutine acc_copyout_finalize(a, len)} | |
4511 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4512 | @item @tab @code{integer len} | |
4513 | @item @emph{Interface}: @tab @code{subroutine acc_copyout_finalize_async(a, async)} | |
4514 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4515 | @item @tab @code{integer(acc_handle_kind) :: async} | |
4516 | @item @emph{Interface}: @tab @code{subroutine acc_copyout_finalize_async(a, len, async)} | |
4517 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4518 | @item @tab @code{integer len} | |
4519 | @item @tab @code{integer(acc_handle_kind) :: async} | |
4520 | @end multitable | |
4521 | ||
4522 | @item @emph{Reference}: | |
4523 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4524 | 3.2.22. | |
4525 | @end table | |
4526 | ||
4527 | ||
4528 | ||
4529 | @node acc_delete | |
4530 | @section @code{acc_delete} -- Free device memory. | |
4531 | @table @asis | |
4532 | @item @emph{Description} | |
4533 | This function frees previously allocated device memory specified by | |
4534 | the device address @var{a} and the length of @var{len} bytes. | |
4535 | ||
4536 | In Fortran, two (2) forms are supported. In the first form, @var{a} specifies | |
4537 | a contiguous array section. The second form @var{a} specifies a variable or | |
4538 | array element and @var{len} specifies the length in bytes. | |
4539 | ||
4540 | @item @emph{C/C++}: | |
4541 | @multitable @columnfractions .20 .80 | |
4542 | @item @emph{Prototype}: @tab @code{acc_delete(h_void *a, size_t len);} | |
4543 | @item @emph{Prototype}: @tab @code{acc_delete_async(h_void *a, size_t len, int async);} | |
4544 | @item @emph{Prototype}: @tab @code{acc_delete_finalize(h_void *a, size_t len);} | |
4545 | @item @emph{Prototype}: @tab @code{acc_delete_finalize_async(h_void *a, size_t len, int async);} | |
4546 | @end multitable | |
4547 | ||
4548 | @item @emph{Fortran}: | |
4549 | @multitable @columnfractions .20 .80 | |
4550 | @item @emph{Interface}: @tab @code{subroutine acc_delete(a)} | |
4551 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4552 | @item @emph{Interface}: @tab @code{subroutine acc_delete(a, len)} | |
4553 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4554 | @item @tab @code{integer len} | |
4555 | @item @emph{Interface}: @tab @code{subroutine acc_delete_async(a, async)} | |
4556 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4557 | @item @tab @code{integer(acc_handle_kind) :: async} | |
4558 | @item @emph{Interface}: @tab @code{subroutine acc_delete_async(a, len, async)} | |
4559 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4560 | @item @tab @code{integer len} | |
4561 | @item @tab @code{integer(acc_handle_kind) :: async} | |
4562 | @item @emph{Interface}: @tab @code{subroutine acc_delete_finalize(a)} | |
4563 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4564 | @item @emph{Interface}: @tab @code{subroutine acc_delete_finalize(a, len)} | |
4565 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4566 | @item @tab @code{integer len} | |
4567 | @item @emph{Interface}: @tab @code{subroutine acc_delete_async_finalize(a, async)} | |
4568 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4569 | @item @tab @code{integer(acc_handle_kind) :: async} | |
4570 | @item @emph{Interface}: @tab @code{subroutine acc_delete_async_finalize(a, len, async)} | |
4571 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4572 | @item @tab @code{integer len} | |
4573 | @item @tab @code{integer(acc_handle_kind) :: async} | |
4574 | @end multitable | |
4575 | ||
4576 | @item @emph{Reference}: | |
4577 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4578 | 3.2.23. | |
4579 | @end table | |
4580 | ||
4581 | ||
4582 | ||
4583 | @node acc_update_device | |
4584 | @section @code{acc_update_device} -- Update device memory from mapped host memory. | |
4585 | @table @asis | |
4586 | @item @emph{Description} | |
4587 | This function updates the device copy from the previously mapped host memory. | |
4588 | The host memory is specified with the host address @var{a} and a length of | |
4589 | @var{len} bytes. | |
4590 | ||
4591 | In Fortran, two (2) forms are supported. In the first form, @var{a} specifies | |
4592 | a contiguous array section. The second form @var{a} specifies a variable or | |
4593 | array element and @var{len} specifies the length in bytes. | |
4594 | ||
4595 | @item @emph{C/C++}: | |
4596 | @multitable @columnfractions .20 .80 | |
4597 | @item @emph{Prototype}: @tab @code{acc_update_device(h_void *a, size_t len);} | |
4598 | @item @emph{Prototype}: @tab @code{acc_update_device(h_void *a, size_t len, async);} | |
4599 | @end multitable | |
4600 | ||
4601 | @item @emph{Fortran}: | |
4602 | @multitable @columnfractions .20 .80 | |
4603 | @item @emph{Interface}: @tab @code{subroutine acc_update_device(a)} | |
4604 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4605 | @item @emph{Interface}: @tab @code{subroutine acc_update_device(a, len)} | |
4606 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4607 | @item @tab @code{integer len} | |
4608 | @item @emph{Interface}: @tab @code{subroutine acc_update_device_async(a, async)} | |
4609 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4610 | @item @tab @code{integer(acc_handle_kind) :: async} | |
4611 | @item @emph{Interface}: @tab @code{subroutine acc_update_device_async(a, len, async)} | |
4612 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4613 | @item @tab @code{integer len} | |
4614 | @item @tab @code{integer(acc_handle_kind) :: async} | |
4615 | @end multitable | |
4616 | ||
4617 | @item @emph{Reference}: | |
4618 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4619 | 3.2.24. | |
4620 | @end table | |
4621 | ||
4622 | ||
4623 | ||
4624 | @node acc_update_self | |
4625 | @section @code{acc_update_self} -- Update host memory from mapped device memory. | |
4626 | @table @asis | |
4627 | @item @emph{Description} | |
4628 | This function updates the host copy from the previously mapped device memory. | |
4629 | The host memory is specified with the host address @var{a} and a length of | |
4630 | @var{len} bytes. | |
4631 | ||
4632 | In Fortran, two (2) forms are supported. In the first form, @var{a} specifies | |
4633 | a contiguous array section. The second form @var{a} specifies a variable or | |
4634 | array element and @var{len} specifies the length in bytes. | |
4635 | ||
4636 | @item @emph{C/C++}: | |
4637 | @multitable @columnfractions .20 .80 | |
4638 | @item @emph{Prototype}: @tab @code{acc_update_self(h_void *a, size_t len);} | |
4639 | @item @emph{Prototype}: @tab @code{acc_update_self_async(h_void *a, size_t len, int async);} | |
4640 | @end multitable | |
4641 | ||
4642 | @item @emph{Fortran}: | |
4643 | @multitable @columnfractions .20 .80 | |
4644 | @item @emph{Interface}: @tab @code{subroutine acc_update_self(a)} | |
4645 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4646 | @item @emph{Interface}: @tab @code{subroutine acc_update_self(a, len)} | |
4647 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4648 | @item @tab @code{integer len} | |
4649 | @item @emph{Interface}: @tab @code{subroutine acc_update_self_async(a, async)} | |
4650 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4651 | @item @tab @code{integer(acc_handle_kind) :: async} | |
4652 | @item @emph{Interface}: @tab @code{subroutine acc_update_self_async(a, len, async)} | |
4653 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4654 | @item @tab @code{integer len} | |
4655 | @item @tab @code{integer(acc_handle_kind) :: async} | |
4656 | @end multitable | |
4657 | ||
4658 | @item @emph{Reference}: | |
4659 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4660 | 3.2.25. | |
4661 | @end table | |
4662 | ||
4663 | ||
4664 | ||
4665 | @node acc_map_data | |
4666 | @section @code{acc_map_data} -- Map previously allocated device memory to host memory. | |
4667 | @table @asis | |
4668 | @item @emph{Description} | |
4669 | This function maps previously allocated device and host memory. The device | |
4670 | memory is specified with the device address @var{d}. The host memory is | |
4671 | specified with the host address @var{h} and a length of @var{len}. | |
4672 | ||
4673 | @item @emph{C/C++}: | |
4674 | @multitable @columnfractions .20 .80 | |
4675 | @item @emph{Prototype}: @tab @code{acc_map_data(h_void *h, d_void *d, size_t len);} | |
4676 | @end multitable | |
4677 | ||
4678 | @item @emph{Reference}: | |
4679 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4680 | 3.2.26. | |
4681 | @end table | |
4682 | ||
4683 | ||
4684 | ||
4685 | @node acc_unmap_data | |
4686 | @section @code{acc_unmap_data} -- Unmap device memory from host memory. | |
4687 | @table @asis | |
4688 | @item @emph{Description} | |
4689 | This function unmaps previously mapped device and host memory. The latter | |
4690 | specified by @var{h}. | |
4691 | ||
4692 | @item @emph{C/C++}: | |
4693 | @multitable @columnfractions .20 .80 | |
4694 | @item @emph{Prototype}: @tab @code{acc_unmap_data(h_void *h);} | |
4695 | @end multitable | |
4696 | ||
4697 | @item @emph{Reference}: | |
4698 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4699 | 3.2.27. | |
4700 | @end table | |
4701 | ||
4702 | ||
4703 | ||
4704 | @node acc_deviceptr | |
4705 | @section @code{acc_deviceptr} -- Get device pointer associated with specific host address. | |
4706 | @table @asis | |
4707 | @item @emph{Description} | |
4708 | This function returns the device address that has been mapped to the | |
4709 | host address specified by @var{h}. | |
4710 | ||
4711 | @item @emph{C/C++}: | |
4712 | @multitable @columnfractions .20 .80 | |
4713 | @item @emph{Prototype}: @tab @code{void *acc_deviceptr(h_void *h);} | |
4714 | @end multitable | |
4715 | ||
4716 | @item @emph{Reference}: | |
4717 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4718 | 3.2.28. | |
4719 | @end table | |
4720 | ||
4721 | ||
4722 | ||
4723 | @node acc_hostptr | |
4724 | @section @code{acc_hostptr} -- Get host pointer associated with specific device address. | |
4725 | @table @asis | |
4726 | @item @emph{Description} | |
4727 | This function returns the host address that has been mapped to the | |
4728 | device address specified by @var{d}. | |
4729 | ||
4730 | @item @emph{C/C++}: | |
4731 | @multitable @columnfractions .20 .80 | |
4732 | @item @emph{Prototype}: @tab @code{void *acc_hostptr(d_void *d);} | |
4733 | @end multitable | |
4734 | ||
4735 | @item @emph{Reference}: | |
4736 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4737 | 3.2.29. | |
4738 | @end table | |
4739 | ||
4740 | ||
4741 | ||
4742 | @node acc_is_present | |
4743 | @section @code{acc_is_present} -- Indicate whether host variable / array is present on device. | |
4744 | @table @asis | |
4745 | @item @emph{Description} | |
4746 | This function indicates whether the specified host address in @var{a} and a | |
4747 | length of @var{len} bytes is present on the device. In C/C++, a non-zero | |
4748 | value is returned to indicate the presence of the mapped memory on the | |
4749 | device. A zero is returned to indicate the memory is not mapped on the | |
4750 | device. | |
4751 | ||
4752 | In Fortran, two (2) forms are supported. In the first form, @var{a} specifies | |
4753 | a contiguous array section. The second form @var{a} specifies a variable or | |
4754 | array element and @var{len} specifies the length in bytes. If the host | |
4755 | memory is mapped to device memory, then a @code{true} is returned. Otherwise, | |
4756 | a @code{false} is return to indicate the mapped memory is not present. | |
4757 | ||
4758 | @item @emph{C/C++}: | |
4759 | @multitable @columnfractions .20 .80 | |
4760 | @item @emph{Prototype}: @tab @code{int acc_is_present(h_void *a, size_t len);} | |
4761 | @end multitable | |
4762 | ||
4763 | @item @emph{Fortran}: | |
4764 | @multitable @columnfractions .20 .80 | |
4765 | @item @emph{Interface}: @tab @code{function acc_is_present(a)} | |
4766 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4767 | @item @tab @code{logical acc_is_present} | |
4768 | @item @emph{Interface}: @tab @code{function acc_is_present(a, len)} | |
4769 | @item @tab @code{type, dimension(:[,:]...) :: a} | |
4770 | @item @tab @code{integer len} | |
4771 | @item @tab @code{logical acc_is_present} | |
4772 | @end multitable | |
4773 | ||
4774 | @item @emph{Reference}: | |
4775 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4776 | 3.2.30. | |
4777 | @end table | |
4778 | ||
4779 | ||
4780 | ||
4781 | @node acc_memcpy_to_device | |
4782 | @section @code{acc_memcpy_to_device} -- Copy host memory to device memory. | |
4783 | @table @asis | |
4784 | @item @emph{Description} | |
4785 | This function copies host memory specified by host address of @var{src} to | |
4786 | device memory specified by the device address @var{dest} for a length of | |
4787 | @var{bytes} bytes. | |
4788 | ||
4789 | @item @emph{C/C++}: | |
4790 | @multitable @columnfractions .20 .80 | |
4791 | @item @emph{Prototype}: @tab @code{acc_memcpy_to_device(d_void *dest, h_void *src, size_t bytes);} | |
4792 | @end multitable | |
4793 | ||
4794 | @item @emph{Reference}: | |
4795 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4796 | 3.2.31. | |
4797 | @end table | |
4798 | ||
4799 | ||
4800 | ||
4801 | @node acc_memcpy_from_device | |
4802 | @section @code{acc_memcpy_from_device} -- Copy device memory to host memory. | |
4803 | @table @asis | |
4804 | @item @emph{Description} | |
4805 | This function copies host memory specified by host address of @var{src} from | |
4806 | device memory specified by the device address @var{dest} for a length of | |
4807 | @var{bytes} bytes. | |
4808 | ||
4809 | @item @emph{C/C++}: | |
4810 | @multitable @columnfractions .20 .80 | |
4811 | @item @emph{Prototype}: @tab @code{acc_memcpy_from_device(d_void *dest, h_void *src, size_t bytes);} | |
4812 | @end multitable | |
4813 | ||
4814 | @item @emph{Reference}: | |
4815 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4816 | 3.2.32. | |
4817 | @end table | |
4818 | ||
4819 | ||
4820 | ||
4821 | @node acc_attach | |
4822 | @section @code{acc_attach} -- Let device pointer point to device-pointer target. | |
4823 | @table @asis | |
4824 | @item @emph{Description} | |
4825 | This function updates a pointer on the device from pointing to a host-pointer | |
4826 | address to pointing to the corresponding device data. | |
4827 | ||
4828 | @item @emph{C/C++}: | |
4829 | @multitable @columnfractions .20 .80 | |
4830 | @item @emph{Prototype}: @tab @code{acc_attach(h_void **ptr);} | |
4831 | @item @emph{Prototype}: @tab @code{acc_attach_async(h_void **ptr, int async);} | |
4832 | @end multitable | |
4833 | ||
4834 | @item @emph{Reference}: | |
4835 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4836 | 3.2.34. | |
4837 | @end table | |
4838 | ||
4839 | ||
4840 | ||
4841 | @node acc_detach | |
4842 | @section @code{acc_detach} -- Let device pointer point to host-pointer target. | |
4843 | @table @asis | |
4844 | @item @emph{Description} | |
4845 | This function updates a pointer on the device from pointing to a device-pointer | |
4846 | address to pointing to the corresponding host data. | |
4847 | ||
4848 | @item @emph{C/C++}: | |
4849 | @multitable @columnfractions .20 .80 | |
4850 | @item @emph{Prototype}: @tab @code{acc_detach(h_void **ptr);} | |
4851 | @item @emph{Prototype}: @tab @code{acc_detach_async(h_void **ptr, int async);} | |
4852 | @item @emph{Prototype}: @tab @code{acc_detach_finalize(h_void **ptr);} | |
4853 | @item @emph{Prototype}: @tab @code{acc_detach_finalize_async(h_void **ptr, int async);} | |
4854 | @end multitable | |
4855 | ||
4856 | @item @emph{Reference}: | |
4857 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4858 | 3.2.35. | |
4859 | @end table | |
4860 | ||
4861 | ||
4862 | ||
4863 | @node acc_get_current_cuda_device | |
4864 | @section @code{acc_get_current_cuda_device} -- Get CUDA device handle. | |
4865 | @table @asis | |
4866 | @item @emph{Description} | |
4867 | This function returns the CUDA device handle. This handle is the same | |
4868 | as used by the CUDA Runtime or Driver API's. | |
4869 | ||
4870 | @item @emph{C/C++}: | |
4871 | @multitable @columnfractions .20 .80 | |
4872 | @item @emph{Prototype}: @tab @code{void *acc_get_current_cuda_device(void);} | |
4873 | @end multitable | |
4874 | ||
4875 | @item @emph{Reference}: | |
4876 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4877 | A.2.1.1. | |
4878 | @end table | |
4879 | ||
4880 | ||
4881 | ||
4882 | @node acc_get_current_cuda_context | |
4883 | @section @code{acc_get_current_cuda_context} -- Get CUDA context handle. | |
4884 | @table @asis | |
4885 | @item @emph{Description} | |
4886 | This function returns the CUDA context handle. This handle is the same | |
4887 | as used by the CUDA Runtime or Driver API's. | |
4888 | ||
4889 | @item @emph{C/C++}: | |
4890 | @multitable @columnfractions .20 .80 | |
4891 | @item @emph{Prototype}: @tab @code{void *acc_get_current_cuda_context(void);} | |
4892 | @end multitable | |
4893 | ||
4894 | @item @emph{Reference}: | |
4895 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4896 | A.2.1.2. | |
4897 | @end table | |
4898 | ||
4899 | ||
4900 | ||
4901 | @node acc_get_cuda_stream | |
4902 | @section @code{acc_get_cuda_stream} -- Get CUDA stream handle. | |
4903 | @table @asis | |
4904 | @item @emph{Description} | |
4905 | This function returns the CUDA stream handle for the queue @var{async}. | |
4906 | This handle is the same as used by the CUDA Runtime or Driver API's. | |
4907 | ||
4908 | @item @emph{C/C++}: | |
4909 | @multitable @columnfractions .20 .80 | |
4910 | @item @emph{Prototype}: @tab @code{void *acc_get_cuda_stream(int async);} | |
4911 | @end multitable | |
4912 | ||
4913 | @item @emph{Reference}: | |
4914 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4915 | A.2.1.3. | |
4916 | @end table | |
4917 | ||
4918 | ||
4919 | ||
4920 | @node acc_set_cuda_stream | |
4921 | @section @code{acc_set_cuda_stream} -- Set CUDA stream handle. | |
4922 | @table @asis | |
4923 | @item @emph{Description} | |
4924 | This function associates the stream handle specified by @var{stream} with | |
4925 | the queue @var{async}. | |
4926 | ||
4927 | This cannot be used to change the stream handle associated with | |
4928 | @code{acc_async_sync}. | |
4929 | ||
4930 | The return value is not specified. | |
4931 | ||
4932 | @item @emph{C/C++}: | |
4933 | @multitable @columnfractions .20 .80 | |
4934 | @item @emph{Prototype}: @tab @code{int acc_set_cuda_stream(int async, void *stream);} | |
4935 | @end multitable | |
4936 | ||
4937 | @item @emph{Reference}: | |
4938 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4939 | A.2.1.4. | |
4940 | @end table | |
4941 | ||
4942 | ||
4943 | ||
4944 | @node acc_prof_register | |
4945 | @section @code{acc_prof_register} -- Register callbacks. | |
4946 | @table @asis | |
4947 | @item @emph{Description}: | |
4948 | This function registers callbacks. | |
4949 | ||
4950 | @item @emph{C/C++}: | |
4951 | @multitable @columnfractions .20 .80 | |
4952 | @item @emph{Prototype}: @tab @code{void acc_prof_register (acc_event_t, acc_prof_callback, acc_register_t);} | |
4953 | @end multitable | |
4954 | ||
4955 | @item @emph{See also}: | |
4956 | @ref{OpenACC Profiling Interface} | |
4957 | ||
4958 | @item @emph{Reference}: | |
4959 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4960 | 5.3. | |
4961 | @end table | |
4962 | ||
4963 | ||
4964 | ||
4965 | @node acc_prof_unregister | |
4966 | @section @code{acc_prof_unregister} -- Unregister callbacks. | |
4967 | @table @asis | |
4968 | @item @emph{Description}: | |
4969 | This function unregisters callbacks. | |
4970 | ||
4971 | @item @emph{C/C++}: | |
4972 | @multitable @columnfractions .20 .80 | |
4973 | @item @emph{Prototype}: @tab @code{void acc_prof_unregister (acc_event_t, acc_prof_callback, acc_register_t);} | |
4974 | @end multitable | |
4975 | ||
4976 | @item @emph{See also}: | |
4977 | @ref{OpenACC Profiling Interface} | |
4978 | ||
4979 | @item @emph{Reference}: | |
4980 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
4981 | 5.3. | |
4982 | @end table | |
4983 | ||
4984 | ||
4985 | ||
4986 | @node acc_prof_lookup | |
4987 | @section @code{acc_prof_lookup} -- Obtain inquiry functions. | |
4988 | @table @asis | |
4989 | @item @emph{Description}: | |
4990 | Function to obtain inquiry functions. | |
4991 | ||
4992 | @item @emph{C/C++}: | |
4993 | @multitable @columnfractions .20 .80 | |
4994 | @item @emph{Prototype}: @tab @code{acc_query_fn acc_prof_lookup (const char *);} | |
4995 | @end multitable | |
4996 | ||
4997 | @item @emph{See also}: | |
4998 | @ref{OpenACC Profiling Interface} | |
4999 | ||
5000 | @item @emph{Reference}: | |
5001 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
5002 | 5.3. | |
5003 | @end table | |
5004 | ||
5005 | ||
5006 | ||
5007 | @node acc_register_library | |
5008 | @section @code{acc_register_library} -- Library registration. | |
5009 | @table @asis | |
5010 | @item @emph{Description}: | |
5011 | Function for library registration. | |
5012 | ||
5013 | @item @emph{C/C++}: | |
5014 | @multitable @columnfractions .20 .80 | |
5015 | @item @emph{Prototype}: @tab @code{void acc_register_library (acc_prof_reg, acc_prof_reg, acc_prof_lookup_func);} | |
5016 | @end multitable | |
5017 | ||
5018 | @item @emph{See also}: | |
5019 | @ref{OpenACC Profiling Interface}, @ref{ACC_PROFLIB} | |
5020 | ||
5021 | @item @emph{Reference}: | |
5022 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
5023 | 5.3. | |
5024 | @end table | |
5025 | ||
5026 | ||
5027 | ||
5028 | @c --------------------------------------------------------------------- | |
5029 | @c OpenACC Environment Variables | |
5030 | @c --------------------------------------------------------------------- | |
5031 | ||
5032 | @node OpenACC Environment Variables | |
5033 | @chapter OpenACC Environment Variables | |
5034 | ||
5035 | The variables @env{ACC_DEVICE_TYPE} and @env{ACC_DEVICE_NUM} | |
5036 | are defined by section 4 of the OpenACC specification in version 2.0. | |
5037 | The variable @env{ACC_PROFLIB} | |
5038 | is defined by section 4 of the OpenACC specification in version 2.6. | |
d77de738 ML |
5039 | |
5040 | @menu | |
5041 | * ACC_DEVICE_TYPE:: | |
5042 | * ACC_DEVICE_NUM:: | |
5043 | * ACC_PROFLIB:: | |
d77de738 ML |
5044 | @end menu |
5045 | ||
5046 | ||
5047 | ||
5048 | @node ACC_DEVICE_TYPE | |
5049 | @section @code{ACC_DEVICE_TYPE} | |
5050 | @table @asis | |
67f5d368 TB |
5051 | @item @emph{Description}: |
5052 | Control the default device type to use when executing compute regions. | |
5053 | If unset, the code can be run on any device type, favoring a non-host | |
5054 | device type. | |
5055 | ||
5056 | Supported values in GCC (if compiled in) are | |
5057 | @itemize | |
5058 | @item @code{host} | |
5059 | @item @code{nvidia} | |
5060 | @item @code{radeon} | |
5061 | @end itemize | |
d77de738 ML |
5062 | @item @emph{Reference}: |
5063 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
5064 | 4.1. | |
5065 | @end table | |
5066 | ||
5067 | ||
5068 | ||
5069 | @node ACC_DEVICE_NUM | |
5070 | @section @code{ACC_DEVICE_NUM} | |
5071 | @table @asis | |
67f5d368 TB |
5072 | @item @emph{Description}: |
5073 | Control which device, identified by device number, is the default device. | |
5074 | The value must be a nonnegative integer less than the number of devices. | |
5075 | If unset, device number zero is used. | |
d77de738 ML |
5076 | @item @emph{Reference}: |
5077 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
5078 | 4.2. | |
5079 | @end table | |
5080 | ||
5081 | ||
5082 | ||
5083 | @node ACC_PROFLIB | |
5084 | @section @code{ACC_PROFLIB} | |
5085 | @table @asis | |
67f5d368 TB |
5086 | @item @emph{Description}: |
5087 | Semicolon-separated list of dynamic libraries that are loaded as profiling | |
5088 | libraries. Each library must provide at least the @code{acc_register_library} | |
5089 | routine. Each library file is found as described by the documentation of | |
5090 | @code{dlopen} of your operating system. | |
d77de738 ML |
5091 | @item @emph{See also}: |
5092 | @ref{acc_register_library}, @ref{OpenACC Profiling Interface} | |
5093 | ||
5094 | @item @emph{Reference}: | |
5095 | @uref{https://www.openacc.org, OpenACC specification v2.6}, section | |
5096 | 4.3. | |
5097 | @end table | |
5098 | ||
5099 | ||
5100 | ||
d77de738 ML |
5101 | @c --------------------------------------------------------------------- |
5102 | @c CUDA Streams Usage | |
5103 | @c --------------------------------------------------------------------- | |
5104 | ||
5105 | @node CUDA Streams Usage | |
5106 | @chapter CUDA Streams Usage | |
5107 | ||
5108 | This applies to the @code{nvptx} plugin only. | |
5109 | ||
5110 | The library provides elements that perform asynchronous movement of | |
5111 | data and asynchronous operation of computing constructs. This | |
5112 | asynchronous functionality is implemented by making use of CUDA | |
5113 | streams@footnote{See "Stream Management" in "CUDA Driver API", | |
5114 | TRM-06703-001, Version 5.5, for additional information}. | |
5115 | ||
5116 | The primary means by that the asynchronous functionality is accessed | |
5117 | is through the use of those OpenACC directives which make use of the | |
5118 | @code{async} and @code{wait} clauses. When the @code{async} clause is | |
5119 | first used with a directive, it creates a CUDA stream. If an | |
5120 | @code{async-argument} is used with the @code{async} clause, then the | |
5121 | stream is associated with the specified @code{async-argument}. | |
5122 | ||
5123 | Following the creation of an association between a CUDA stream and the | |
5124 | @code{async-argument} of an @code{async} clause, both the @code{wait} | |
5125 | clause and the @code{wait} directive can be used. When either the | |
5126 | clause or directive is used after stream creation, it creates a | |
5127 | rendezvous point whereby execution waits until all operations | |
5128 | associated with the @code{async-argument}, that is, stream, have | |
5129 | completed. | |
5130 | ||
5131 | Normally, the management of the streams that are created as a result of | |
5132 | using the @code{async} clause, is done without any intervention by the | |
5133 | caller. This implies the association between the @code{async-argument} | |
15886c03 | 5134 | and the CUDA stream is maintained for the lifetime of the program. |
d77de738 ML |
5135 | However, this association can be changed through the use of the library |
5136 | function @code{acc_set_cuda_stream}. When the function | |
5137 | @code{acc_set_cuda_stream} is called, the CUDA stream that was | |
15886c03 | 5138 | originally associated with the @code{async} clause is destroyed. |
d77de738 ML |
5139 | Caution should be taken when changing the association as subsequent |
5140 | references to the @code{async-argument} refer to a different | |
5141 | CUDA stream. | |
5142 | ||
5143 | ||
5144 | ||
5145 | @c --------------------------------------------------------------------- | |
5146 | @c OpenACC Library Interoperability | |
5147 | @c --------------------------------------------------------------------- | |
5148 | ||
5149 | @node OpenACC Library Interoperability | |
5150 | @chapter OpenACC Library Interoperability | |
5151 | ||
5152 | @section Introduction | |
5153 | ||
5154 | The OpenACC library uses the CUDA Driver API, and may interact with | |
5155 | programs that use the Runtime library directly, or another library | |
5156 | based on the Runtime library, e.g., CUBLAS@footnote{See section 2.26, | |
5157 | "Interactions with the CUDA Driver API" in | |
5158 | "CUDA Runtime API", Version 5.5, and section 2.27, "VDPAU | |
5159 | Interoperability", in "CUDA Driver API", TRM-06703-001, Version 5.5, | |
5160 | for additional information on library interoperability.}. | |
5161 | This chapter describes the use cases and what changes are | |
5162 | required in order to use both the OpenACC library and the CUBLAS and Runtime | |
5163 | libraries within a program. | |
5164 | ||
5165 | @section First invocation: NVIDIA CUBLAS library API | |
5166 | ||
5167 | In this first use case (see below), a function in the CUBLAS library is called | |
5168 | prior to any of the functions in the OpenACC library. More specifically, the | |
5169 | function @code{cublasCreate()}. | |
5170 | ||
5171 | When invoked, the function initializes the library and allocates the | |
5172 | hardware resources on the host and the device on behalf of the caller. Once | |
5173 | the initialization and allocation has completed, a handle is returned to the | |
5174 | caller. The OpenACC library also requires initialization and allocation of | |
5175 | hardware resources. Since the CUBLAS library has already allocated the | |
5176 | hardware resources for the device, all that is left to do is to initialize | |
5177 | the OpenACC library and acquire the hardware resources on the host. | |
5178 | ||
5179 | Prior to calling the OpenACC function that initializes the library and | |
5180 | allocate the host hardware resources, you need to acquire the device number | |
5181 | that was allocated during the call to @code{cublasCreate()}. The invoking of the | |
5182 | runtime library function @code{cudaGetDevice()} accomplishes this. Once | |
5183 | acquired, the device number is passed along with the device type as | |
5184 | parameters to the OpenACC library function @code{acc_set_device_num()}. | |
5185 | ||
5186 | Once the call to @code{acc_set_device_num()} has completed, the OpenACC | |
5187 | library uses the context that was created during the call to | |
15886c03 | 5188 | @code{cublasCreate()}. In other words, both libraries share the |
d77de738 ML |
5189 | same context. |
5190 | ||
5191 | @smallexample | |
5192 | /* Create the handle */ | |
5193 | s = cublasCreate(&h); | |
5194 | if (s != CUBLAS_STATUS_SUCCESS) | |
5195 | @{ | |
5196 | fprintf(stderr, "cublasCreate failed %d\n", s); | |
5197 | exit(EXIT_FAILURE); | |
5198 | @} | |
5199 | ||
5200 | /* Get the device number */ | |
5201 | e = cudaGetDevice(&dev); | |
5202 | if (e != cudaSuccess) | |
5203 | @{ | |
5204 | fprintf(stderr, "cudaGetDevice failed %d\n", e); | |
5205 | exit(EXIT_FAILURE); | |
5206 | @} | |
5207 | ||
5208 | /* Initialize OpenACC library and use device 'dev' */ | |
5209 | acc_set_device_num(dev, acc_device_nvidia); | |
5210 | ||
5211 | @end smallexample | |
5212 | @center Use Case 1 | |
5213 | ||
5214 | @section First invocation: OpenACC library API | |
5215 | ||
5216 | In this second use case (see below), a function in the OpenACC library is | |
eda38850 | 5217 | called prior to any of the functions in the CUBLAS library. More specifically, |
d77de738 ML |
5218 | the function @code{acc_set_device_num()}. |
5219 | ||
5220 | In the use case presented here, the function @code{acc_set_device_num()} | |
5221 | is used to both initialize the OpenACC library and allocate the hardware | |
5222 | resources on the host and the device. In the call to the function, the | |
5223 | call parameters specify which device to use and what device | |
5224 | type to use, i.e., @code{acc_device_nvidia}. It should be noted that this | |
5225 | is but one method to initialize the OpenACC library and allocate the | |
5226 | appropriate hardware resources. Other methods are available through the | |
15886c03 | 5227 | use of environment variables and these is discussed in the next section. |
d77de738 ML |
5228 | |
5229 | Once the call to @code{acc_set_device_num()} has completed, other OpenACC | |
5230 | functions can be called as seen with multiple calls being made to | |
5231 | @code{acc_copyin()}. In addition, calls can be made to functions in the | |
5232 | CUBLAS library. In the use case a call to @code{cublasCreate()} is made | |
5233 | subsequent to the calls to @code{acc_copyin()}. | |
5234 | As seen in the previous use case, a call to @code{cublasCreate()} | |
5235 | initializes the CUBLAS library and allocates the hardware resources on the | |
5236 | host and the device. However, since the device has already been allocated, | |
15886c03 | 5237 | @code{cublasCreate()} only initializes the CUBLAS library and allocates |
d77de738 ML |
5238 | the appropriate hardware resources on the host. The context that was created |
5239 | as part of the OpenACC initialization is shared with the CUBLAS library, | |
5240 | similarly to the first use case. | |
5241 | ||
5242 | @smallexample | |
5243 | dev = 0; | |
5244 | ||
5245 | acc_set_device_num(dev, acc_device_nvidia); | |
5246 | ||
5247 | /* Copy the first set to the device */ | |
5248 | d_X = acc_copyin(&h_X[0], N * sizeof (float)); | |
5249 | if (d_X == NULL) | |
5250 | @{ | |
5251 | fprintf(stderr, "copyin error h_X\n"); | |
5252 | exit(EXIT_FAILURE); | |
5253 | @} | |
5254 | ||
5255 | /* Copy the second set to the device */ | |
5256 | d_Y = acc_copyin(&h_Y1[0], N * sizeof (float)); | |
5257 | if (d_Y == NULL) | |
5258 | @{ | |
5259 | fprintf(stderr, "copyin error h_Y1\n"); | |
5260 | exit(EXIT_FAILURE); | |
5261 | @} | |
5262 | ||
5263 | /* Create the handle */ | |
5264 | s = cublasCreate(&h); | |
5265 | if (s != CUBLAS_STATUS_SUCCESS) | |
5266 | @{ | |
5267 | fprintf(stderr, "cublasCreate failed %d\n", s); | |
5268 | exit(EXIT_FAILURE); | |
5269 | @} | |
5270 | ||
5271 | /* Perform saxpy using CUBLAS library function */ | |
5272 | s = cublasSaxpy(h, N, &alpha, d_X, 1, d_Y, 1); | |
5273 | if (s != CUBLAS_STATUS_SUCCESS) | |
5274 | @{ | |
5275 | fprintf(stderr, "cublasSaxpy failed %d\n", s); | |
5276 | exit(EXIT_FAILURE); | |
5277 | @} | |
5278 | ||
5279 | /* Copy the results from the device */ | |
5280 | acc_memcpy_from_device(&h_Y1[0], d_Y, N * sizeof (float)); | |
5281 | ||
5282 | @end smallexample | |
5283 | @center Use Case 2 | |
5284 | ||
5285 | @section OpenACC library and environment variables | |
5286 | ||
5287 | There are two environment variables associated with the OpenACC library | |
5288 | that may be used to control the device type and device number: | |
5289 | @env{ACC_DEVICE_TYPE} and @env{ACC_DEVICE_NUM}, respectively. These two | |
5290 | environment variables can be used as an alternative to calling | |
5291 | @code{acc_set_device_num()}. As seen in the second use case, the device | |
5292 | type and device number were specified using @code{acc_set_device_num()}. | |
5293 | If however, the aforementioned environment variables were set, then the | |
5294 | call to @code{acc_set_device_num()} would not be required. | |
5295 | ||
5296 | ||
5297 | The use of the environment variables is only relevant when an OpenACC function | |
5298 | is called prior to a call to @code{cudaCreate()}. If @code{cudaCreate()} | |
5299 | is called prior to a call to an OpenACC function, then you must call | |
5300 | @code{acc_set_device_num()}@footnote{More complete information | |
5301 | about @env{ACC_DEVICE_TYPE} and @env{ACC_DEVICE_NUM} can be found in | |
5302 | sections 4.1 and 4.2 of the @uref{https://www.openacc.org, OpenACC} | |
5303 | Application Programming Interface”, Version 2.6.} | |
5304 | ||
5305 | ||
5306 | ||
5307 | @c --------------------------------------------------------------------- | |
5308 | @c OpenACC Profiling Interface | |
5309 | @c --------------------------------------------------------------------- | |
5310 | ||
5311 | @node OpenACC Profiling Interface | |
5312 | @chapter OpenACC Profiling Interface | |
5313 | ||
5314 | @section Implementation Status and Implementation-Defined Behavior | |
5315 | ||
5316 | We're implementing the OpenACC Profiling Interface as defined by the | |
5317 | OpenACC 2.6 specification. We're clarifying some aspects here as | |
5318 | @emph{implementation-defined behavior}, while they're still under | |
5319 | discussion within the OpenACC Technical Committee. | |
5320 | ||
5321 | This implementation is tuned to keep the performance impact as low as | |
5322 | possible for the (very common) case that the Profiling Interface is | |
5323 | not enabled. This is relevant, as the Profiling Interface affects all | |
5324 | the @emph{hot} code paths (in the target code, not in the offloaded | |
5325 | code). Users of the OpenACC Profiling Interface can be expected to | |
15886c03 TB |
5326 | understand that performance is impacted to some degree once the |
5327 | Profiling Interface is enabled: for example, because of the | |
d77de738 ML |
5328 | @emph{runtime} (libgomp) calling into a third-party @emph{library} for |
5329 | every event that has been registered. | |
5330 | ||
5331 | We're not yet accounting for the fact that @cite{OpenACC events may | |
5332 | occur during event processing}. | |
5333 | We just handle one case specially, as required by CUDA 9.0 | |
5334 | @command{nvprof}, that @code{acc_get_device_type} | |
5335 | (@ref{acc_get_device_type})) may be called from | |
5336 | @code{acc_ev_device_init_start}, @code{acc_ev_device_init_end} | |
5337 | callbacks. | |
5338 | ||
5339 | We're not yet implementing initialization via a | |
5340 | @code{acc_register_library} function that is either statically linked | |
5341 | in, or dynamically via @env{LD_PRELOAD}. | |
5342 | Initialization via @code{acc_register_library} functions dynamically | |
5343 | loaded via the @env{ACC_PROFLIB} environment variable does work, as | |
5344 | does directly calling @code{acc_prof_register}, | |
5345 | @code{acc_prof_unregister}, @code{acc_prof_lookup}. | |
5346 | ||
5347 | As currently there are no inquiry functions defined, calls to | |
15886c03 | 5348 | @code{acc_prof_lookup} always returns @code{NULL}. |
d77de738 ML |
5349 | |
5350 | There aren't separate @emph{start}, @emph{stop} events defined for the | |
5351 | event types @code{acc_ev_create}, @code{acc_ev_delete}, | |
5352 | @code{acc_ev_alloc}, @code{acc_ev_free}. It's not clear if these | |
5353 | should be triggered before or after the actual device-specific call is | |
5354 | made. We trigger them after. | |
5355 | ||
5356 | Remarks about data provided to callbacks: | |
5357 | ||
5358 | @table @asis | |
5359 | ||
5360 | @item @code{acc_prof_info.event_type} | |
5361 | It's not clear if for @emph{nested} event callbacks (for example, | |
5362 | @code{acc_ev_enqueue_launch_start} as part of a parent compute | |
5363 | construct), this should be set for the nested event | |
5364 | (@code{acc_ev_enqueue_launch_start}), or if the value of the parent | |
5365 | construct should remain (@code{acc_ev_compute_construct_start}). In | |
15886c03 | 5366 | this implementation, the value generally corresponds to the |
d77de738 ML |
5367 | innermost nested event type. |
5368 | ||
5369 | @item @code{acc_prof_info.device_type} | |
5370 | @itemize | |
5371 | ||
5372 | @item | |
5373 | For @code{acc_ev_compute_construct_start}, and in presence of an | |
15886c03 | 5374 | @code{if} clause with @emph{false} argument, this still refers to |
d77de738 ML |
5375 | the offloading device type. |
5376 | It's not clear if that's the expected behavior. | |
5377 | ||
5378 | @item | |
5379 | Complementary to the item before, for | |
5380 | @code{acc_ev_compute_construct_end}, this is set to | |
5381 | @code{acc_device_host} in presence of an @code{if} clause with | |
5382 | @emph{false} argument. | |
5383 | It's not clear if that's the expected behavior. | |
5384 | ||
5385 | @end itemize | |
5386 | ||
5387 | @item @code{acc_prof_info.thread_id} | |
5388 | Always @code{-1}; not yet implemented. | |
5389 | ||
5390 | @item @code{acc_prof_info.async} | |
5391 | @itemize | |
5392 | ||
5393 | @item | |
5394 | Not yet implemented correctly for | |
5395 | @code{acc_ev_compute_construct_start}. | |
5396 | ||
5397 | @item | |
5398 | In a compute construct, for host-fallback | |
15886c03 | 5399 | execution/@code{acc_device_host} it always is |
d77de738 | 5400 | @code{acc_async_sync}. |
15886c03 | 5401 | It is unclear if that is the expected behavior. |
d77de738 ML |
5402 | |
5403 | @item | |
5404 | For @code{acc_ev_device_init_start} and @code{acc_ev_device_init_end}, | |
5405 | it will always be @code{acc_async_sync}. | |
15886c03 | 5406 | It is unclear if that is the expected behavior. |
d77de738 ML |
5407 | |
5408 | @end itemize | |
5409 | ||
5410 | @item @code{acc_prof_info.async_queue} | |
5411 | There is no @cite{limited number of asynchronous queues} in libgomp. | |
15886c03 | 5412 | This always has the same value as @code{acc_prof_info.async}. |
d77de738 ML |
5413 | |
5414 | @item @code{acc_prof_info.src_file} | |
5415 | Always @code{NULL}; not yet implemented. | |
5416 | ||
5417 | @item @code{acc_prof_info.func_name} | |
5418 | Always @code{NULL}; not yet implemented. | |
5419 | ||
5420 | @item @code{acc_prof_info.line_no} | |
5421 | Always @code{-1}; not yet implemented. | |
5422 | ||
5423 | @item @code{acc_prof_info.end_line_no} | |
5424 | Always @code{-1}; not yet implemented. | |
5425 | ||
5426 | @item @code{acc_prof_info.func_line_no} | |
5427 | Always @code{-1}; not yet implemented. | |
5428 | ||
5429 | @item @code{acc_prof_info.func_end_line_no} | |
5430 | Always @code{-1}; not yet implemented. | |
5431 | ||
5432 | @item @code{acc_event_info.event_type}, @code{acc_event_info.*.event_type} | |
5433 | Relating to @code{acc_prof_info.event_type} discussed above, in this | |
5434 | implementation, this will always be the same value as | |
5435 | @code{acc_prof_info.event_type}. | |
5436 | ||
5437 | @item @code{acc_event_info.*.parent_construct} | |
5438 | @itemize | |
5439 | ||
5440 | @item | |
5441 | Will be @code{acc_construct_parallel} for all OpenACC compute | |
5442 | constructs as well as many OpenACC Runtime API calls; should be the | |
5443 | one matching the actual construct, or | |
5444 | @code{acc_construct_runtime_api}, respectively. | |
5445 | ||
5446 | @item | |
5447 | Will be @code{acc_construct_enter_data} or | |
5448 | @code{acc_construct_exit_data} when processing variable mappings | |
5449 | specified in OpenACC @emph{declare} directives; should be | |
5450 | @code{acc_construct_declare}. | |
5451 | ||
5452 | @item | |
5453 | For implicit @code{acc_ev_device_init_start}, | |
5454 | @code{acc_ev_device_init_end}, and explicit as well as implicit | |
5455 | @code{acc_ev_alloc}, @code{acc_ev_free}, | |
5456 | @code{acc_ev_enqueue_upload_start}, @code{acc_ev_enqueue_upload_end}, | |
5457 | @code{acc_ev_enqueue_download_start}, and | |
5458 | @code{acc_ev_enqueue_download_end}, will be | |
5459 | @code{acc_construct_parallel}; should reflect the real parent | |
5460 | construct. | |
5461 | ||
5462 | @end itemize | |
5463 | ||
5464 | @item @code{acc_event_info.*.implicit} | |
5465 | For @code{acc_ev_alloc}, @code{acc_ev_free}, | |
5466 | @code{acc_ev_enqueue_upload_start}, @code{acc_ev_enqueue_upload_end}, | |
5467 | @code{acc_ev_enqueue_download_start}, and | |
5468 | @code{acc_ev_enqueue_download_end}, this currently will be @code{1} | |
5469 | also for explicit usage. | |
5470 | ||
5471 | @item @code{acc_event_info.data_event.var_name} | |
5472 | Always @code{NULL}; not yet implemented. | |
5473 | ||
5474 | @item @code{acc_event_info.data_event.host_ptr} | |
5475 | For @code{acc_ev_alloc}, and @code{acc_ev_free}, this is always | |
5476 | @code{NULL}. | |
5477 | ||
5478 | @item @code{typedef union acc_api_info} | |
5479 | @dots{} as printed in @cite{5.2.3. Third Argument: API-Specific | |
5480 | Information}. This should obviously be @code{typedef @emph{struct} | |
5481 | acc_api_info}. | |
5482 | ||
5483 | @item @code{acc_api_info.device_api} | |
5484 | Possibly not yet implemented correctly for | |
5485 | @code{acc_ev_compute_construct_start}, | |
5486 | @code{acc_ev_device_init_start}, @code{acc_ev_device_init_end}: | |
5487 | will always be @code{acc_device_api_none} for these event types. | |
5488 | For @code{acc_ev_enter_data_start}, it will be | |
5489 | @code{acc_device_api_none} in some cases. | |
5490 | ||
5491 | @item @code{acc_api_info.device_type} | |
5492 | Always the same as @code{acc_prof_info.device_type}. | |
5493 | ||
5494 | @item @code{acc_api_info.vendor} | |
5495 | Always @code{-1}; not yet implemented. | |
5496 | ||
5497 | @item @code{acc_api_info.device_handle} | |
5498 | Always @code{NULL}; not yet implemented. | |
5499 | ||
5500 | @item @code{acc_api_info.context_handle} | |
5501 | Always @code{NULL}; not yet implemented. | |
5502 | ||
5503 | @item @code{acc_api_info.async_handle} | |
5504 | Always @code{NULL}; not yet implemented. | |
5505 | ||
5506 | @end table | |
5507 | ||
5508 | Remarks about certain event types: | |
5509 | ||
5510 | @table @asis | |
5511 | ||
5512 | @item @code{acc_ev_device_init_start}, @code{acc_ev_device_init_end} | |
5513 | @itemize | |
5514 | ||
5515 | @item | |
5516 | @c See 'DEVICE_INIT_INSIDE_COMPUTE_CONSTRUCT' in | |
5517 | @c 'libgomp.oacc-c-c++-common/acc_prof-kernels-1.c', | |
5518 | @c 'libgomp.oacc-c-c++-common/acc_prof-parallel-1.c'. | |
5519 | When a compute construct triggers implicit | |
5520 | @code{acc_ev_device_init_start} and @code{acc_ev_device_init_end} | |
5521 | events, they currently aren't @emph{nested within} the corresponding | |
5522 | @code{acc_ev_compute_construct_start} and | |
5523 | @code{acc_ev_compute_construct_end}, but they're currently observed | |
5524 | @emph{before} @code{acc_ev_compute_construct_start}. | |
5525 | It's not clear what to do: the standard asks us provide a lot of | |
5526 | details to the @code{acc_ev_compute_construct_start} callback, without | |
5527 | (implicitly) initializing a device before? | |
5528 | ||
5529 | @item | |
5530 | Callbacks for these event types will not be invoked for calls to the | |
5531 | @code{acc_set_device_type} and @code{acc_set_device_num} functions. | |
5532 | It's not clear if they should be. | |
5533 | ||
5534 | @end itemize | |
5535 | ||
5536 | @item @code{acc_ev_enter_data_start}, @code{acc_ev_enter_data_end}, @code{acc_ev_exit_data_start}, @code{acc_ev_exit_data_end} | |
5537 | @itemize | |
5538 | ||
5539 | @item | |
5540 | Callbacks for these event types will also be invoked for OpenACC | |
5541 | @emph{host_data} constructs. | |
5542 | It's not clear if they should be. | |
5543 | ||
5544 | @item | |
5545 | Callbacks for these event types will also be invoked when processing | |
5546 | variable mappings specified in OpenACC @emph{declare} directives. | |
5547 | It's not clear if they should be. | |
5548 | ||
5549 | @end itemize | |
5550 | ||
5551 | @end table | |
5552 | ||
5553 | Callbacks for the following event types will be invoked, but dispatch | |
5554 | and information provided therein has not yet been thoroughly reviewed: | |
5555 | ||
5556 | @itemize | |
5557 | @item @code{acc_ev_alloc} | |
5558 | @item @code{acc_ev_free} | |
5559 | @item @code{acc_ev_update_start}, @code{acc_ev_update_end} | |
5560 | @item @code{acc_ev_enqueue_upload_start}, @code{acc_ev_enqueue_upload_end} | |
5561 | @item @code{acc_ev_enqueue_download_start}, @code{acc_ev_enqueue_download_end} | |
5562 | @end itemize | |
5563 | ||
5564 | During device initialization, and finalization, respectively, | |
5565 | callbacks for the following event types will not yet be invoked: | |
5566 | ||
5567 | @itemize | |
5568 | @item @code{acc_ev_alloc} | |
5569 | @item @code{acc_ev_free} | |
5570 | @end itemize | |
5571 | ||
5572 | Callbacks for the following event types have not yet been implemented, | |
5573 | so currently won't be invoked: | |
5574 | ||
5575 | @itemize | |
5576 | @item @code{acc_ev_device_shutdown_start}, @code{acc_ev_device_shutdown_end} | |
5577 | @item @code{acc_ev_runtime_shutdown} | |
5578 | @item @code{acc_ev_create}, @code{acc_ev_delete} | |
5579 | @item @code{acc_ev_wait_start}, @code{acc_ev_wait_end} | |
5580 | @end itemize | |
5581 | ||
5582 | For the following runtime library functions, not all expected | |
5583 | callbacks will be invoked (mostly concerning implicit device | |
5584 | initialization): | |
5585 | ||
5586 | @itemize | |
5587 | @item @code{acc_get_num_devices} | |
5588 | @item @code{acc_set_device_type} | |
5589 | @item @code{acc_get_device_type} | |
5590 | @item @code{acc_set_device_num} | |
5591 | @item @code{acc_get_device_num} | |
5592 | @item @code{acc_init} | |
5593 | @item @code{acc_shutdown} | |
5594 | @end itemize | |
5595 | ||
5596 | Aside from implicit device initialization, for the following runtime | |
5597 | library functions, no callbacks will be invoked for shared-memory | |
5598 | offloading devices (it's not clear if they should be): | |
5599 | ||
5600 | @itemize | |
5601 | @item @code{acc_malloc} | |
5602 | @item @code{acc_free} | |
5603 | @item @code{acc_copyin}, @code{acc_present_or_copyin}, @code{acc_copyin_async} | |
5604 | @item @code{acc_create}, @code{acc_present_or_create}, @code{acc_create_async} | |
5605 | @item @code{acc_copyout}, @code{acc_copyout_async}, @code{acc_copyout_finalize}, @code{acc_copyout_finalize_async} | |
5606 | @item @code{acc_delete}, @code{acc_delete_async}, @code{acc_delete_finalize}, @code{acc_delete_finalize_async} | |
5607 | @item @code{acc_update_device}, @code{acc_update_device_async} | |
5608 | @item @code{acc_update_self}, @code{acc_update_self_async} | |
5609 | @item @code{acc_map_data}, @code{acc_unmap_data} | |
5610 | @item @code{acc_memcpy_to_device}, @code{acc_memcpy_to_device_async} | |
5611 | @item @code{acc_memcpy_from_device}, @code{acc_memcpy_from_device_async} | |
5612 | @end itemize | |
5613 | ||
5614 | @c --------------------------------------------------------------------- | |
5615 | @c OpenMP-Implementation Specifics | |
5616 | @c --------------------------------------------------------------------- | |
5617 | ||
5618 | @node OpenMP-Implementation Specifics | |
5619 | @chapter OpenMP-Implementation Specifics | |
5620 | ||
5621 | @menu | |
2cd0689a | 5622 | * Implementation-defined ICV Initialization:: |
d77de738 | 5623 | * OpenMP Context Selectors:: |
450b05ce | 5624 | * Memory allocation:: |
d77de738 ML |
5625 | @end menu |
5626 | ||
2cd0689a TB |
5627 | @node Implementation-defined ICV Initialization |
5628 | @section Implementation-defined ICV Initialization | |
5629 | @cindex Implementation specific setting | |
5630 | ||
5631 | @multitable @columnfractions .30 .70 | |
5632 | @item @var{affinity-format-var} @tab See @ref{OMP_AFFINITY_FORMAT}. | |
5633 | @item @var{def-allocator-var} @tab See @ref{OMP_ALLOCATOR}. | |
5634 | @item @var{max-active-levels-var} @tab See @ref{OMP_MAX_ACTIVE_LEVELS}. | |
5635 | @item @var{dyn-var} @tab See @ref{OMP_DYNAMIC}. | |
819f3d36 | 5636 | @item @var{nthreads-var} @tab See @ref{OMP_NUM_THREADS}. |
2cd0689a TB |
5637 | @item @var{num-devices-var} @tab Number of non-host devices found |
5638 | by GCC's run-time library | |
5639 | @item @var{num-procs-var} @tab The number of CPU cores on the | |
5640 | initial device, except that affinity settings might lead to a | |
5641 | smaller number. On non-host devices, the value of the | |
5642 | @var{nthreads-var} ICV. | |
5643 | @item @var{place-partition-var} @tab See @ref{OMP_PLACES}. | |
5644 | @item @var{run-sched-var} @tab See @ref{OMP_SCHEDULE}. | |
5645 | @item @var{stacksize-var} @tab See @ref{OMP_STACKSIZE}. | |
5646 | @item @var{thread-limit-var} @tab See @ref{OMP_TEAMS_THREAD_LIMIT} | |
5647 | @item @var{wait-policy-var} @tab See @ref{OMP_WAIT_POLICY} and | |
5648 | @ref{GOMP_SPINCOUNT} | |
5649 | @end multitable | |
5650 | ||
d77de738 ML |
5651 | @node OpenMP Context Selectors |
5652 | @section OpenMP Context Selectors | |
5653 | ||
5654 | @code{vendor} is always @code{gnu}. References are to the GCC manual. | |
5655 | ||
75e3773b TB |
5656 | @c NOTE: Only the following selectors have been implemented. To add |
5657 | @c additional traits for target architecture, TARGET_OMP_DEVICE_KIND_ARCH_ISA | |
5658 | @c has to be implemented; cf. also PR target/105640. | |
5659 | @c For offload devices, add *additionally* gcc/config/*/t-omp-device. | |
5660 | ||
5661 | For the host compiler, @code{kind} always matches @code{host}; for the | |
5662 | offloading architectures AMD GCN and Nvidia PTX, @code{kind} always matches | |
5663 | @code{gpu}. For the x86 family of computers, AMD GCN and Nvidia PTX | |
5664 | the following traits are supported in addition; while OpenMP is supported | |
5665 | on more architectures, GCC currently does not match any @code{arch} or | |
5666 | @code{isa} traits for those. | |
5667 | ||
5668 | @multitable @columnfractions .65 .30 | |
5669 | @headitem @code{arch} @tab @code{isa} | |
d77de738 ML |
5670 | @item @code{x86}, @code{x86_64}, @code{i386}, @code{i486}, |
5671 | @code{i586}, @code{i686}, @code{ia32} | |
d77de738 ML |
5672 | @tab See @code{-m...} flags in ``x86 Options'' (without @code{-m}) |
5673 | @item @code{amdgcn}, @code{gcn} | |
e0b95c2e TB |
5674 | @tab See @code{-march=} in ``AMD GCN Options''@footnote{Additionally, |
5675 | @code{gfx803} is supported as an alias for @code{fiji}.} | |
d77de738 | 5676 | @item @code{nvptx} |
d77de738 ML |
5677 | @tab See @code{-march=} in ``Nvidia PTX Options'' |
5678 | @end multitable | |
5679 | ||
450b05ce TB |
5680 | @node Memory allocation |
5681 | @section Memory allocation | |
d77de738 | 5682 | |
bc238c40 TB |
5683 | The description below applies to: |
5684 | ||
5685 | @itemize | |
5686 | @item Explicit use of the OpenMP API routines, see | |
5687 | @ref{Memory Management Routines}. | |
5688 | @item The @code{allocate} clause, except when the @code{allocator} modifier is a | |
5689 | constant expression with value @code{omp_default_mem_alloc} and no | |
5690 | @code{align} modifier has been specified. (In that case, the normal | |
5691 | @code{malloc} allocation is used.) | |
5692 | @item Using the @code{allocate} directive for automatic/stack variables, except | |
5693 | when the @code{allocator} clause is a constant expression with value | |
5694 | @code{omp_default_mem_alloc} and no @code{align} clause has been | |
5695 | specified. (In that case, the normal allocation is used: stack allocation | |
5696 | and, sometimes for Fortran, also @code{malloc} [depending on flags such as | |
5697 | @option{-fstack-arrays}].) | |
5698 | @item Using the @code{allocate} directive for variable in static memory is | |
5699 | currently not supported (compile time error). | |
5700 | @item Using the @code{allocators} directive for Fortran pointers and | |
5701 | allocatables is currently not supported (compile time error). | |
5702 | @end itemize | |
5703 | ||
a85a106c TB |
5704 | For the available predefined allocators and, as applicable, their associated |
5705 | predefined memory spaces and for the available traits and their default values, | |
5706 | see @ref{OMP_ALLOCATOR}. Predefined allocators without an associated memory | |
5707 | space use the @code{omp_default_mem_space} memory space. | |
5708 | ||
8c2fc744 TB |
5709 | For the memory spaces, the following applies: |
5710 | @itemize | |
5711 | @item @code{omp_default_mem_space} is supported | |
5712 | @item @code{omp_const_mem_space} maps to @code{omp_default_mem_space} | |
5713 | @item @code{omp_low_lat_mem_space} maps to @code{omp_default_mem_space} | |
5714 | @item @code{omp_large_cap_mem_space} maps to @code{omp_default_mem_space}, | |
5715 | unless the memkind library is available | |
5716 | @item @code{omp_high_bw_mem_space} maps to @code{omp_default_mem_space}, | |
5717 | unless the memkind library is available | |
5718 | @end itemize | |
5719 | ||
d77de738 ML |
5720 | On Linux systems, where the @uref{https://github.com/memkind/memkind, memkind |
5721 | library} (@code{libmemkind.so.0}) is available at runtime, it is used when | |
5722 | creating memory allocators requesting | |
5723 | ||
5724 | @itemize | |
5725 | @item the memory space @code{omp_high_bw_mem_space} | |
5726 | @item the memory space @code{omp_large_cap_mem_space} | |
450b05ce | 5727 | @item the @code{partition} trait @code{interleaved}; note that for |
8c2fc744 | 5728 | @code{omp_large_cap_mem_space} the allocation will not be interleaved |
d77de738 ML |
5729 | @end itemize |
5730 | ||
450b05ce TB |
5731 | On Linux systems, where the @uref{https://github.com/numactl/numactl, numa |
5732 | library} (@code{libnuma.so.1}) is available at runtime, it used when creating | |
5733 | memory allocators requesting | |
5734 | ||
5735 | @itemize | |
5736 | @item the @code{partition} trait @code{nearest}, except when both the | |
5737 | libmemkind library is available and the memory space is either | |
5738 | @code{omp_large_cap_mem_space} or @code{omp_high_bw_mem_space} | |
5739 | @end itemize | |
5740 | ||
5741 | Note that the numa library will round up the allocation size to a multiple of | |
5742 | the system page size; therefore, consider using it only with large data or | |
5743 | by sharing allocations via the @code{pool_size} trait. Furthermore, the Linux | |
5744 | kernel does not guarantee that an allocation will always be on the nearest NUMA | |
5745 | node nor that after reallocation the same node will be used. Note additionally | |
5746 | that, on Linux, the default setting of the memory placement policy is to use the | |
5747 | current node; therefore, unless the memory placement policy has been overridden, | |
5748 | the @code{partition} trait @code{environment} (the default) will be effectively | |
5749 | a @code{nearest} allocation. | |
5750 | ||
a85a106c | 5751 | Additional notes regarding the traits: |
8c2fc744 TB |
5752 | @itemize |
5753 | @item The @code{pinned} trait is unsupported. | |
a85a106c TB |
5754 | @item The default for the @code{pool_size} trait is no pool and for every |
5755 | (re)allocation the associated library routine is called, which might | |
5756 | internally use a memory pool. | |
8c2fc744 TB |
5757 | @item For the @code{partition} trait, the partition part size will be the same |
5758 | as the requested size (i.e. @code{interleaved} or @code{blocked} has no | |
5759 | effect), except for @code{interleaved} when the memkind library is | |
450b05ce TB |
5760 | available. Furthermore, for @code{nearest} and unless the numa library |
5761 | is available, the memory might not be on the same NUMA node as thread | |
5762 | that allocated the memory; on Linux, this is in particular the case when | |
5763 | the memory placement policy is set to preferred. | |
8c2fc744 TB |
5764 | @item The @code{access} trait has no effect such that memory is always |
5765 | accessible by all threads. | |
5766 | @item The @code{sync_hint} trait has no effect. | |
5767 | @end itemize | |
d77de738 ML |
5768 | |
5769 | @c --------------------------------------------------------------------- | |
5770 | @c Offload-Target Specifics | |
5771 | @c --------------------------------------------------------------------- | |
5772 | ||
5773 | @node Offload-Target Specifics | |
5774 | @chapter Offload-Target Specifics | |
5775 | ||
5776 | The following sections present notes on the offload-target specifics | |
5777 | ||
5778 | @menu | |
5779 | * AMD Radeon:: | |
5780 | * nvptx:: | |
5781 | @end menu | |
5782 | ||
5783 | @node AMD Radeon | |
5784 | @section AMD Radeon (GCN) | |
5785 | ||
5786 | On the hardware side, there is the hierarchy (fine to coarse): | |
5787 | @itemize | |
5788 | @item work item (thread) | |
5789 | @item wavefront | |
5790 | @item work group | |
81476bc4 | 5791 | @item compute unit (CU) |
d77de738 ML |
5792 | @end itemize |
5793 | ||
5794 | All OpenMP and OpenACC levels are used, i.e. | |
5795 | @itemize | |
5796 | @item OpenMP's simd and OpenACC's vector map to work items (thread) | |
5797 | @item OpenMP's threads (``parallel'') and OpenACC's workers map | |
5798 | to wavefronts | |
5799 | @item OpenMP's teams and OpenACC's gang use a threadpool with the | |
5800 | size of the number of teams or gangs, respectively. | |
5801 | @end itemize | |
5802 | ||
5803 | The used sizes are | |
5804 | @itemize | |
5805 | @item Number of teams is the specified @code{num_teams} (OpenMP) or | |
81476bc4 MV |
5806 | @code{num_gangs} (OpenACC) or otherwise the number of CU. It is limited |
5807 | by two times the number of CU. | |
d77de738 ML |
5808 | @item Number of wavefronts is 4 for gfx900 and 16 otherwise; |
5809 | @code{num_threads} (OpenMP) and @code{num_workers} (OpenACC) | |
5810 | overrides this if smaller. | |
5811 | @item The wavefront has 102 scalars and 64 vectors | |
5812 | @item Number of workitems is always 64 | |
5813 | @item The hardware permits maximally 40 workgroups/CU and | |
5814 | 16 wavefronts/workgroup up to a limit of 40 wavefronts in total per CU. | |
5815 | @item 80 scalars registers and 24 vector registers in non-kernel functions | |
5816 | (the chosen procedure-calling API). | |
5817 | @item For the kernel itself: as many as register pressure demands (number of | |
5818 | teams and number of threads, scaled down if registers are exhausted) | |
5819 | @end itemize | |
5820 | ||
5821 | The implementation remark: | |
5822 | @itemize | |
5823 | @item I/O within OpenMP target regions and OpenACC parallel/kernels is supported | |
5824 | using the C library @code{printf} functions and the Fortran | |
5825 | @code{print}/@code{write} statements. | |
243fa488 | 5826 | @item Reverse offload regions (i.e. @code{target} regions with |
f84fdb13 TB |
5827 | @code{device(ancestor:1)}) are processed serially per @code{target} region |
5828 | such that the next reverse offload region is only executed after the previous | |
5829 | one returned. | |
f1af7d65 | 5830 | @item OpenMP code that has a @code{requires} directive with |
f84fdb13 TB |
5831 | @code{unified_shared_memory} will remove any GCN device from the list of |
5832 | available devices (``host fallback''). | |
2e3dd14d TB |
5833 | @item The available stack size can be changed using the @code{GCN_STACK_SIZE} |
5834 | environment variable; the default is 32 kiB per thread. | |
d77de738 ML |
5835 | @end itemize |
5836 | ||
5837 | ||
5838 | ||
5839 | @node nvptx | |
5840 | @section nvptx | |
5841 | ||
5842 | On the hardware side, there is the hierarchy (fine to coarse): | |
5843 | @itemize | |
5844 | @item thread | |
5845 | @item warp | |
5846 | @item thread block | |
5847 | @item streaming multiprocessor | |
5848 | @end itemize | |
5849 | ||
5850 | All OpenMP and OpenACC levels are used, i.e. | |
5851 | @itemize | |
5852 | @item OpenMP's simd and OpenACC's vector map to threads | |
5853 | @item OpenMP's threads (``parallel'') and OpenACC's workers map to warps | |
5854 | @item OpenMP's teams and OpenACC's gang use a threadpool with the | |
5855 | size of the number of teams or gangs, respectively. | |
5856 | @end itemize | |
5857 | ||
5858 | The used sizes are | |
5859 | @itemize | |
5860 | @item The @code{warp_size} is always 32 | |
5861 | @item CUDA kernel launched: @code{dim=@{#teams,1,1@}, blocks=@{#threads,warp_size,1@}}. | |
81476bc4 MV |
5862 | @item The number of teams is limited by the number of blocks the device can |
5863 | host simultaneously. | |
d77de738 ML |
5864 | @end itemize |
5865 | ||
5866 | Additional information can be obtained by setting the environment variable to | |
5867 | @code{GOMP_DEBUG=1} (very verbose; grep for @code{kernel.*launch} for launch | |
5868 | parameters). | |
5869 | ||
5870 | GCC generates generic PTX ISA code, which is just-in-time compiled by CUDA, | |
5871 | which caches the JIT in the user's directory (see CUDA documentation; can be | |
5872 | tuned by the environment variables @code{CUDA_CACHE_@{DISABLE,MAXSIZE,PATH@}}. | |
5873 | ||
5874 | Note: While PTX ISA is generic, the @code{-mptx=} and @code{-march=} commandline | |
eda38850 | 5875 | options still affect the used PTX ISA code and, thus, the requirements on |
d77de738 ML |
5876 | CUDA version and hardware. |
5877 | ||
5878 | The implementation remark: | |
5879 | @itemize | |
5880 | @item I/O within OpenMP target regions and OpenACC parallel/kernels is supported | |
5881 | using the C library @code{printf} functions. Note that the Fortran | |
5882 | @code{print}/@code{write} statements are not supported, yet. | |
5883 | @item Compilation OpenMP code that contains @code{requires reverse_offload} | |
5884 | requires at least @code{-march=sm_35}, compiling for @code{-march=sm_30} | |
5885 | is not supported. | |
eda38850 TB |
5886 | @item For code containing reverse offload (i.e. @code{target} regions with |
5887 | @code{device(ancestor:1)}), there is a slight performance penalty | |
5888 | for @emph{all} target regions, consisting mostly of shutdown delay | |
5889 | Per device, reverse offload regions are processed serially such that | |
5890 | the next reverse offload region is only executed after the previous | |
5891 | one returned. | |
f1af7d65 TB |
5892 | @item OpenMP code that has a @code{requires} directive with |
5893 | @code{unified_shared_memory} will remove any nvptx device from the | |
eda38850 | 5894 | list of available devices (``host fallback''). |
2cd0689a TB |
5895 | @item The default per-warp stack size is 128 kiB; see also @code{-msoft-stack} |
5896 | in the GCC manual. | |
25072a47 TB |
5897 | @item The OpenMP routines @code{omp_target_memcpy_rect} and |
5898 | @code{omp_target_memcpy_rect_async} and the @code{target update} | |
5899 | directive for non-contiguous list items will use the 2D and 3D | |
5900 | memory-copy functions of the CUDA library. Higher dimensions will | |
5901 | call those functions in a loop and are therefore supported. | |
d77de738 ML |
5902 | @end itemize |
5903 | ||
5904 | ||
5905 | @c --------------------------------------------------------------------- | |
5906 | @c The libgomp ABI | |
5907 | @c --------------------------------------------------------------------- | |
5908 | ||
5909 | @node The libgomp ABI | |
5910 | @chapter The libgomp ABI | |
5911 | ||
5912 | The following sections present notes on the external ABI as | |
5913 | presented by libgomp. Only maintainers should need them. | |
5914 | ||
5915 | @menu | |
5916 | * Implementing MASTER construct:: | |
5917 | * Implementing CRITICAL construct:: | |
5918 | * Implementing ATOMIC construct:: | |
5919 | * Implementing FLUSH construct:: | |
5920 | * Implementing BARRIER construct:: | |
5921 | * Implementing THREADPRIVATE construct:: | |
5922 | * Implementing PRIVATE clause:: | |
5923 | * Implementing FIRSTPRIVATE LASTPRIVATE COPYIN and COPYPRIVATE clauses:: | |
5924 | * Implementing REDUCTION clause:: | |
5925 | * Implementing PARALLEL construct:: | |
5926 | * Implementing FOR construct:: | |
5927 | * Implementing ORDERED construct:: | |
5928 | * Implementing SECTIONS construct:: | |
5929 | * Implementing SINGLE construct:: | |
5930 | * Implementing OpenACC's PARALLEL construct:: | |
5931 | @end menu | |
5932 | ||
5933 | ||
5934 | @node Implementing MASTER construct | |
5935 | @section Implementing MASTER construct | |
5936 | ||
5937 | @smallexample | |
5938 | if (omp_get_thread_num () == 0) | |
5939 | block | |
5940 | @end smallexample | |
5941 | ||
5942 | Alternately, we generate two copies of the parallel subfunction | |
5943 | and only include this in the version run by the primary thread. | |
5944 | Surely this is not worthwhile though... | |
5945 | ||
5946 | ||
5947 | ||
5948 | @node Implementing CRITICAL construct | |
5949 | @section Implementing CRITICAL construct | |
5950 | ||
5951 | Without a specified name, | |
5952 | ||
5953 | @smallexample | |
5954 | void GOMP_critical_start (void); | |
5955 | void GOMP_critical_end (void); | |
5956 | @end smallexample | |
5957 | ||
5958 | so that we don't get COPY relocations from libgomp to the main | |
5959 | application. | |
5960 | ||
5961 | With a specified name, use omp_set_lock and omp_unset_lock with | |
5962 | name being transformed into a variable declared like | |
5963 | ||
5964 | @smallexample | |
5965 | omp_lock_t gomp_critical_user_<name> __attribute__((common)) | |
5966 | @end smallexample | |
5967 | ||
5968 | Ideally the ABI would specify that all zero is a valid unlocked | |
5969 | state, and so we wouldn't need to initialize this at | |
5970 | startup. | |
5971 | ||
5972 | ||
5973 | ||
5974 | @node Implementing ATOMIC construct | |
5975 | @section Implementing ATOMIC construct | |
5976 | ||
5977 | The target should implement the @code{__sync} builtins. | |
5978 | ||
5979 | Failing that we could add | |
5980 | ||
5981 | @smallexample | |
5982 | void GOMP_atomic_enter (void) | |
5983 | void GOMP_atomic_exit (void) | |
5984 | @end smallexample | |
5985 | ||
5986 | which reuses the regular lock code, but with yet another lock | |
5987 | object private to the library. | |
5988 | ||
5989 | ||
5990 | ||
5991 | @node Implementing FLUSH construct | |
5992 | @section Implementing FLUSH construct | |
5993 | ||
5994 | Expands to the @code{__sync_synchronize} builtin. | |
5995 | ||
5996 | ||
5997 | ||
5998 | @node Implementing BARRIER construct | |
5999 | @section Implementing BARRIER construct | |
6000 | ||
6001 | @smallexample | |
6002 | void GOMP_barrier (void) | |
6003 | @end smallexample | |
6004 | ||
6005 | ||
6006 | @node Implementing THREADPRIVATE construct | |
6007 | @section Implementing THREADPRIVATE construct | |
6008 | ||
6009 | In _most_ cases we can map this directly to @code{__thread}. Except | |
6010 | that OMP allows constructors for C++ objects. We can either | |
6011 | refuse to support this (how often is it used?) or we can | |
6012 | implement something akin to .ctors. | |
6013 | ||
6014 | Even more ideally, this ctor feature is handled by extensions | |
6015 | to the main pthreads library. Failing that, we can have a set | |
6016 | of entry points to register ctor functions to be called. | |
6017 | ||
6018 | ||
6019 | ||
6020 | @node Implementing PRIVATE clause | |
6021 | @section Implementing PRIVATE clause | |
6022 | ||
6023 | In association with a PARALLEL, or within the lexical extent | |
6024 | of a PARALLEL block, the variable becomes a local variable in | |
6025 | the parallel subfunction. | |
6026 | ||
6027 | In association with FOR or SECTIONS blocks, create a new | |
6028 | automatic variable within the current function. This preserves | |
6029 | the semantic of new variable creation. | |
6030 | ||
6031 | ||
6032 | ||
6033 | @node Implementing FIRSTPRIVATE LASTPRIVATE COPYIN and COPYPRIVATE clauses | |
6034 | @section Implementing FIRSTPRIVATE LASTPRIVATE COPYIN and COPYPRIVATE clauses | |
6035 | ||
6036 | This seems simple enough for PARALLEL blocks. Create a private | |
6037 | struct for communicating between the parent and subfunction. | |
6038 | In the parent, copy in values for scalar and "small" structs; | |
6039 | copy in addresses for others TREE_ADDRESSABLE types. In the | |
6040 | subfunction, copy the value into the local variable. | |
6041 | ||
6042 | It is not clear what to do with bare FOR or SECTION blocks. | |
6043 | The only thing I can figure is that we do something like: | |
6044 | ||
6045 | @smallexample | |
6046 | #pragma omp for firstprivate(x) lastprivate(y) | |
6047 | for (int i = 0; i < n; ++i) | |
6048 | body; | |
6049 | @end smallexample | |
6050 | ||
6051 | which becomes | |
6052 | ||
6053 | @smallexample | |
6054 | @{ | |
6055 | int x = x, y; | |
6056 | ||
6057 | // for stuff | |
6058 | ||
6059 | if (i == n) | |
6060 | y = y; | |
6061 | @} | |
6062 | @end smallexample | |
6063 | ||
6064 | where the "x=x" and "y=y" assignments actually have different | |
6065 | uids for the two variables, i.e. not something you could write | |
6066 | directly in C. Presumably this only makes sense if the "outer" | |
6067 | x and y are global variables. | |
6068 | ||
6069 | COPYPRIVATE would work the same way, except the structure | |
6070 | broadcast would have to happen via SINGLE machinery instead. | |
6071 | ||
6072 | ||
6073 | ||
6074 | @node Implementing REDUCTION clause | |
6075 | @section Implementing REDUCTION clause | |
6076 | ||
6077 | The private struct mentioned in the previous section should have | |
6078 | a pointer to an array of the type of the variable, indexed by the | |
6079 | thread's @var{team_id}. The thread stores its final value into the | |
6080 | array, and after the barrier, the primary thread iterates over the | |
6081 | array to collect the values. | |
6082 | ||
6083 | ||
6084 | @node Implementing PARALLEL construct | |
6085 | @section Implementing PARALLEL construct | |
6086 | ||
6087 | @smallexample | |
6088 | #pragma omp parallel | |
6089 | @{ | |
6090 | body; | |
6091 | @} | |
6092 | @end smallexample | |
6093 | ||
6094 | becomes | |
6095 | ||
6096 | @smallexample | |
6097 | void subfunction (void *data) | |
6098 | @{ | |
6099 | use data; | |
6100 | body; | |
6101 | @} | |
6102 | ||
6103 | setup data; | |
6104 | GOMP_parallel_start (subfunction, &data, num_threads); | |
6105 | subfunction (&data); | |
6106 | GOMP_parallel_end (); | |
6107 | @end smallexample | |
6108 | ||
6109 | @smallexample | |
6110 | void GOMP_parallel_start (void (*fn)(void *), void *data, unsigned num_threads) | |
6111 | @end smallexample | |
6112 | ||
6113 | The @var{FN} argument is the subfunction to be run in parallel. | |
6114 | ||
6115 | The @var{DATA} argument is a pointer to a structure used to | |
6116 | communicate data in and out of the subfunction, as discussed | |
6117 | above with respect to FIRSTPRIVATE et al. | |
6118 | ||
6119 | The @var{NUM_THREADS} argument is 1 if an IF clause is present | |
6120 | and false, or the value of the NUM_THREADS clause, if | |
6121 | present, or 0. | |
6122 | ||
6123 | The function needs to create the appropriate number of | |
6124 | threads and/or launch them from the dock. It needs to | |
6125 | create the team structure and assign team ids. | |
6126 | ||
6127 | @smallexample | |
6128 | void GOMP_parallel_end (void) | |
6129 | @end smallexample | |
6130 | ||
6131 | Tears down the team and returns us to the previous @code{omp_in_parallel()} state. | |
6132 | ||
6133 | ||
6134 | ||
6135 | @node Implementing FOR construct | |
6136 | @section Implementing FOR construct | |
6137 | ||
6138 | @smallexample | |
6139 | #pragma omp parallel for | |
6140 | for (i = lb; i <= ub; i++) | |
6141 | body; | |
6142 | @end smallexample | |
6143 | ||
6144 | becomes | |
6145 | ||
6146 | @smallexample | |
6147 | void subfunction (void *data) | |
6148 | @{ | |
6149 | long _s0, _e0; | |
6150 | while (GOMP_loop_static_next (&_s0, &_e0)) | |
6151 | @{ | |
6152 | long _e1 = _e0, i; | |
6153 | for (i = _s0; i < _e1; i++) | |
6154 | body; | |
6155 | @} | |
6156 | GOMP_loop_end_nowait (); | |
6157 | @} | |
6158 | ||
6159 | GOMP_parallel_loop_static (subfunction, NULL, 0, lb, ub+1, 1, 0); | |
6160 | subfunction (NULL); | |
6161 | GOMP_parallel_end (); | |
6162 | @end smallexample | |
6163 | ||
6164 | @smallexample | |
6165 | #pragma omp for schedule(runtime) | |
6166 | for (i = 0; i < n; i++) | |
6167 | body; | |
6168 | @end smallexample | |
6169 | ||
6170 | becomes | |
6171 | ||
6172 | @smallexample | |
6173 | @{ | |
6174 | long i, _s0, _e0; | |
6175 | if (GOMP_loop_runtime_start (0, n, 1, &_s0, &_e0)) | |
6176 | do @{ | |
6177 | long _e1 = _e0; | |
6178 | for (i = _s0, i < _e0; i++) | |
6179 | body; | |
6180 | @} while (GOMP_loop_runtime_next (&_s0, _&e0)); | |
6181 | GOMP_loop_end (); | |
6182 | @} | |
6183 | @end smallexample | |
6184 | ||
6185 | Note that while it looks like there is trickiness to propagating | |
6186 | a non-constant STEP, there isn't really. We're explicitly allowed | |
6187 | to evaluate it as many times as we want, and any variables involved | |
6188 | should automatically be handled as PRIVATE or SHARED like any other | |
6189 | variables. So the expression should remain evaluable in the | |
6190 | subfunction. We can also pull it into a local variable if we like, | |
6191 | but since its supposed to remain unchanged, we can also not if we like. | |
6192 | ||
6193 | If we have SCHEDULE(STATIC), and no ORDERED, then we ought to be | |
6194 | able to get away with no work-sharing context at all, since we can | |
6195 | simply perform the arithmetic directly in each thread to divide up | |
6196 | the iterations. Which would mean that we wouldn't need to call any | |
6197 | of these routines. | |
6198 | ||
6199 | There are separate routines for handling loops with an ORDERED | |
6200 | clause. Bookkeeping for that is non-trivial... | |
6201 | ||
6202 | ||
6203 | ||
6204 | @node Implementing ORDERED construct | |
6205 | @section Implementing ORDERED construct | |
6206 | ||
6207 | @smallexample | |
6208 | void GOMP_ordered_start (void) | |
6209 | void GOMP_ordered_end (void) | |
6210 | @end smallexample | |
6211 | ||
6212 | ||
6213 | ||
6214 | @node Implementing SECTIONS construct | |
6215 | @section Implementing SECTIONS construct | |
6216 | ||
6217 | A block as | |
6218 | ||
6219 | @smallexample | |
6220 | #pragma omp sections | |
6221 | @{ | |
6222 | #pragma omp section | |
6223 | stmt1; | |
6224 | #pragma omp section | |
6225 | stmt2; | |
6226 | #pragma omp section | |
6227 | stmt3; | |
6228 | @} | |
6229 | @end smallexample | |
6230 | ||
6231 | becomes | |
6232 | ||
6233 | @smallexample | |
6234 | for (i = GOMP_sections_start (3); i != 0; i = GOMP_sections_next ()) | |
6235 | switch (i) | |
6236 | @{ | |
6237 | case 1: | |
6238 | stmt1; | |
6239 | break; | |
6240 | case 2: | |
6241 | stmt2; | |
6242 | break; | |
6243 | case 3: | |
6244 | stmt3; | |
6245 | break; | |
6246 | @} | |
6247 | GOMP_barrier (); | |
6248 | @end smallexample | |
6249 | ||
6250 | ||
6251 | @node Implementing SINGLE construct | |
6252 | @section Implementing SINGLE construct | |
6253 | ||
6254 | A block like | |
6255 | ||
6256 | @smallexample | |
6257 | #pragma omp single | |
6258 | @{ | |
6259 | body; | |
6260 | @} | |
6261 | @end smallexample | |
6262 | ||
6263 | becomes | |
6264 | ||
6265 | @smallexample | |
6266 | if (GOMP_single_start ()) | |
6267 | body; | |
6268 | GOMP_barrier (); | |
6269 | @end smallexample | |
6270 | ||
6271 | while | |
6272 | ||
6273 | @smallexample | |
6274 | #pragma omp single copyprivate(x) | |
6275 | body; | |
6276 | @end smallexample | |
6277 | ||
6278 | becomes | |
6279 | ||
6280 | @smallexample | |
6281 | datap = GOMP_single_copy_start (); | |
6282 | if (datap == NULL) | |
6283 | @{ | |
6284 | body; | |
6285 | data.x = x; | |
6286 | GOMP_single_copy_end (&data); | |
6287 | @} | |
6288 | else | |
6289 | x = datap->x; | |
6290 | GOMP_barrier (); | |
6291 | @end smallexample | |
6292 | ||
6293 | ||
6294 | ||
6295 | @node Implementing OpenACC's PARALLEL construct | |
6296 | @section Implementing OpenACC's PARALLEL construct | |
6297 | ||
6298 | @smallexample | |
6299 | void GOACC_parallel () | |
6300 | @end smallexample | |
6301 | ||
6302 | ||
6303 | ||
6304 | @c --------------------------------------------------------------------- | |
6305 | @c Reporting Bugs | |
6306 | @c --------------------------------------------------------------------- | |
6307 | ||
6308 | @node Reporting Bugs | |
6309 | @chapter Reporting Bugs | |
6310 | ||
6311 | Bugs in the GNU Offloading and Multi Processing Runtime Library should | |
6312 | be reported via @uref{https://gcc.gnu.org/bugzilla/, Bugzilla}. Please add | |
6313 | "openacc", or "openmp", or both to the keywords field in the bug | |
6314 | report, as appropriate. | |
6315 | ||
6316 | ||
6317 | ||
6318 | @c --------------------------------------------------------------------- | |
6319 | @c GNU General Public License | |
6320 | @c --------------------------------------------------------------------- | |
6321 | ||
6322 | @include gpl_v3.texi | |
6323 | ||
6324 | ||
6325 | ||
6326 | @c --------------------------------------------------------------------- | |
6327 | @c GNU Free Documentation License | |
6328 | @c --------------------------------------------------------------------- | |
6329 | ||
6330 | @include fdl.texi | |
6331 | ||
6332 | ||
6333 | ||
6334 | @c --------------------------------------------------------------------- | |
6335 | @c Funding Free Software | |
6336 | @c --------------------------------------------------------------------- | |
6337 | ||
6338 | @include funding.texi | |
6339 | ||
6340 | @c --------------------------------------------------------------------- | |
6341 | @c Index | |
6342 | @c --------------------------------------------------------------------- | |
6343 | ||
6344 | @node Library Index | |
6345 | @unnumbered Library Index | |
6346 | ||
6347 | @printindex cp | |
6348 | ||
6349 | @bye |