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7adcbafe | 1 | .. Copyright (C) 2015-2022 Free Software Foundation, Inc. |
afed3459 DM |
2 | Originally contributed by David Malcolm <dmalcolm@redhat.com> |
3 | ||
4 | This is free software: you can redistribute it and/or modify it | |
5 | under the terms of the GNU General Public License as published by | |
6 | the Free Software Foundation, either version 3 of the License, or | |
7 | (at your option) any later version. | |
8 | ||
9 | This program is distributed in the hope that it will be useful, but | |
10 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU General Public License | |
15 | along with this program. If not, see | |
786973ce | 16 | <https://www.gnu.org/licenses/>. |
afed3459 DM |
17 | |
18 | .. default-domain:: c | |
19 | ||
20 | Performance | |
21 | =========== | |
22 | ||
23 | The timing API | |
24 | -------------- | |
25 | ||
26 | As of GCC 6, libgccjit exposes a timing API, for printing reports on | |
27 | how long was spent in different parts of code. | |
28 | ||
29 | You can create a :c:type:`gcc_jit_timer` instance, which will | |
30 | measure time spent since its creation. The timer maintains a stack | |
31 | of "timer items": as control flow moves through your code, you can push | |
32 | and pop named items relating to your code onto the stack, and the timer | |
33 | will account the time spent accordingly. | |
34 | ||
35 | You can also asssociate a timer with a :c:type:`gcc_jit_context`, in | |
36 | which case the time spent inside compilation will be subdivided. | |
37 | ||
38 | For example, the following code uses a timer, recording client items | |
39 | "create_code", "compile", and "running code": | |
40 | ||
41 | .. code-block:: c | |
42 | ||
43 | /* Create a timer. */ | |
44 | gcc_jit_timer *timer = gcc_jit_timer_new (); | |
45 | if (!timer) | |
46 | { | |
47 | error ("gcc_jit_timer_new failed"); | |
48 | return -1; | |
49 | } | |
50 | ||
51 | /* Let's repeatedly compile and run some code, accumulating it | |
52 | all into the timer. */ | |
53 | for (int i = 0; i < num_iterations; i++) | |
54 | { | |
55 | /* Create a context and associate it with the timer. */ | |
56 | gcc_jit_context *ctxt = gcc_jit_context_acquire (); | |
57 | if (!ctxt) | |
58 | { | |
59 | error ("gcc_jit_context_acquire failed"); | |
60 | return -1; | |
61 | } | |
62 | gcc_jit_context_set_timer (ctxt, timer); | |
63 | ||
64 | /* Populate the context, timing it as client item "create_code". */ | |
65 | gcc_jit_timer_push (timer, "create_code"); | |
66 | create_code (ctxt); | |
67 | gcc_jit_timer_pop (timer, "create_code"); | |
68 | ||
69 | /* Compile the context, timing it as client item "compile". */ | |
70 | gcc_jit_timer_push (timer, "compile"); | |
71 | result = gcc_jit_context_compile (ctxt); | |
72 | gcc_jit_timer_pop (timer, "compile"); | |
73 | ||
74 | /* Run the generated code, timing it as client item "running code". */ | |
75 | gcc_jit_timer_push (timer, "running code"); | |
76 | run_the_code (ctxt, result); | |
77 | gcc_jit_timer_pop (timer, "running code"); | |
78 | ||
79 | /* Clean up. */ | |
80 | gcc_jit_context_release (ctxt); | |
81 | gcc_jit_result_release (result); | |
82 | } | |
83 | ||
84 | /* Print the accumulated timings. */ | |
85 | gcc_jit_timer_print (timer, stderr); | |
86 | gcc_jit_timer_release (timer); | |
87 | ||
88 | giving output like this, showing the internal GCC items at the top, then | |
89 | client items, then the total:: | |
90 | ||
91 | Execution times (seconds) | |
92 | GCC items: | |
93 | phase setup : 0.29 (14%) usr 0.00 ( 0%) sys 0.32 ( 5%) wall 10661 kB (50%) ggc | |
94 | phase parsing : 0.02 ( 1%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 653 kB ( 3%) ggc | |
95 | phase finalize : 0.01 ( 1%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 0 kB ( 0%) ggc | |
96 | dump files : 0.02 ( 1%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall 0 kB ( 0%) ggc | |
97 | callgraph construction : 0.02 ( 1%) usr 0.01 ( 6%) sys 0.01 ( 0%) wall 242 kB ( 1%) ggc | |
98 | callgraph optimization : 0.03 ( 2%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall 142 kB ( 1%) ggc | |
99 | trivially dead code : 0.01 ( 1%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 0 kB ( 0%) ggc | |
100 | df scan insns : 0.01 ( 1%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 9 kB ( 0%) ggc | |
101 | df live regs : 0.01 ( 1%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall 0 kB ( 0%) ggc | |
102 | inline parameters : 0.02 ( 1%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall 82 kB ( 0%) ggc | |
103 | tree CFG cleanup : 0.01 ( 1%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 0 kB ( 0%) ggc | |
104 | tree PHI insertion : 0.01 ( 1%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall 64 kB ( 0%) ggc | |
105 | tree SSA other : 0.01 ( 1%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall 18 kB ( 0%) ggc | |
106 | expand : 0.01 ( 1%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 398 kB ( 2%) ggc | |
107 | jump : 0.01 ( 1%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 0 kB ( 0%) ggc | |
108 | loop init : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 67 kB ( 0%) ggc | |
109 | integrated RA : 0.02 ( 1%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 2468 kB (12%) ggc | |
110 | thread pro- & epilogue : 0.01 ( 1%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 162 kB ( 1%) ggc | |
111 | final : 0.01 ( 1%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 216 kB ( 1%) ggc | |
112 | rest of compilation : 1.37 (69%) usr 0.00 ( 0%) sys 1.13 (18%) wall 1391 kB ( 6%) ggc | |
113 | assemble JIT code : 0.01 ( 1%) usr 0.00 ( 0%) sys 4.04 (66%) wall 0 kB ( 0%) ggc | |
114 | load JIT result : 0.02 ( 1%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 0 kB ( 0%) ggc | |
115 | JIT client code : 0.00 ( 0%) usr 0.01 ( 6%) sys 0.00 ( 0%) wall 0 kB ( 0%) ggc | |
116 | Client items: | |
117 | create_code : 0.00 ( 0%) usr 0.01 ( 6%) sys 0.00 ( 0%) wall 0 kB ( 0%) ggc | |
118 | compile : 0.36 (18%) usr 0.15 (83%) sys 0.86 (14%) wall 14939 kB (70%) ggc | |
119 | running code : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 0 kB ( 0%) ggc | |
120 | TOTAL : 2.00 0.18 6.12 21444 kB | |
121 | ||
122 | The exact format is intended to be human-readable, and is subject to change. | |
123 | ||
124 | .. macro:: LIBGCCJIT_HAVE_TIMING_API | |
125 | ||
126 | The timer API was added to libgccjit in GCC 6. | |
127 | This macro is only defined in versions of libgccjit.h which have the | |
128 | timer API, and so can be used to guard code that may need to compile | |
129 | against earlier releases:: | |
130 | ||
131 | #ifdef LIBGCCJIT_HAVE_TIMING_API | |
132 | gcc_jit_timer *t = gcc_jit_timer_new (); | |
133 | gcc_jit_context_set_timer (ctxt, t); | |
134 | #endif | |
135 | ||
136 | .. type:: gcc_jit_timer | |
137 | ||
138 | .. function:: gcc_jit_timer * gcc_jit_timer_new(void) | |
139 | ||
140 | Create a :c:type:`gcc_jit_timer` instance, and start timing:: | |
141 | ||
142 | gcc_jit_timer *t = gcc_jit_timer_new (); | |
143 | ||
144 | This API entrypoint was added in :ref:`LIBGCCJIT_ABI_4`; you can test | |
145 | for its presence using | |
146 | ||
147 | .. code-block:: c | |
148 | ||
149 | #ifdef LIBGCCJIT_HAVE_TIMING_API | |
150 | ||
151 | .. function:: void gcc_jit_timer_release(gcc_jit_timer *timer) | |
152 | ||
153 | Release a :c:type:`gcc_jit_timer` instance:: | |
154 | ||
155 | gcc_jit_timer_release (t); | |
156 | ||
157 | This should be called exactly once on a timer. | |
158 | ||
159 | This API entrypoint was added in :ref:`LIBGCCJIT_ABI_4`; you can test | |
160 | for its presence using | |
161 | ||
162 | .. code-block:: c | |
163 | ||
164 | #ifdef LIBGCCJIT_HAVE_TIMING_API | |
165 | ||
166 | .. function:: void gcc_jit_context_set_timer(gcc_jit_context *ctxt, \ | |
167 | gcc_jit_timer *timer) | |
168 | ||
169 | Associate a :c:type:`gcc_jit_timer` instance with a context:: | |
170 | ||
171 | gcc_jit_context_set_timer (ctxt, t); | |
172 | ||
173 | A timer instance can be shared between multiple | |
174 | :c:type:`gcc_jit_context` instances. | |
175 | ||
176 | Timers have no locking, so if you have a multithreaded program, you | |
177 | must provide your own locks if more than one thread could be working | |
178 | with the same timer via timer-associated contexts. | |
179 | ||
180 | This API entrypoint was added in :ref:`LIBGCCJIT_ABI_4`; you can test | |
181 | for its presence using | |
182 | ||
183 | .. code-block:: c | |
184 | ||
185 | #ifdef LIBGCCJIT_HAVE_TIMING_API | |
186 | ||
187 | .. function:: gcc_jit_timer *gcc_jit_context_get_timer(gcc_jit_context *ctxt) | |
188 | ||
189 | Get the timer associated with a context (if any). | |
190 | ||
191 | This API entrypoint was added in :ref:`LIBGCCJIT_ABI_4`; you can test | |
192 | for its presence using | |
193 | ||
194 | .. code-block:: c | |
195 | ||
196 | #ifdef LIBGCCJIT_HAVE_TIMING_API | |
197 | ||
198 | .. function:: void gcc_jit_timer_push(gcc_jit_timer *timer, \ | |
199 | const char *item_name) | |
200 | ||
201 | Push the given item onto the timer's stack:: | |
202 | ||
203 | gcc_jit_timer_push (t, "running code"); | |
204 | run_the_code (ctxt, result); | |
205 | gcc_jit_timer_pop (t, "running code"); | |
206 | ||
207 | This API entrypoint was added in :ref:`LIBGCCJIT_ABI_4`; you can test | |
208 | for its presence using | |
209 | ||
210 | .. code-block:: c | |
211 | ||
212 | #ifdef LIBGCCJIT_HAVE_TIMING_API | |
213 | ||
214 | .. function:: void gcc_jit_timer_pop(gcc_jit_timer *timer, \ | |
215 | const char *item_name) | |
216 | ||
217 | Pop the top item from the timer's stack. | |
218 | ||
219 | If "item_name" is provided, it must match that of the top item. | |
220 | Alternatively, ``NULL`` can be passed in, to suppress checking. | |
221 | ||
222 | This API entrypoint was added in :ref:`LIBGCCJIT_ABI_4`; you can test | |
223 | for its presence using | |
224 | ||
225 | .. code-block:: c | |
226 | ||
227 | #ifdef LIBGCCJIT_HAVE_TIMING_API | |
228 | ||
229 | .. function:: void gcc_jit_timer_print(gcc_jit_timer *timer, \ | |
230 | FILE *f_out) | |
231 | ||
232 | Print timing information to the given stream about activity since | |
233 | the timer was started. | |
234 | ||
235 | This API entrypoint was added in :ref:`LIBGCCJIT_ABI_4`; you can test | |
236 | for its presence using | |
237 | ||
238 | .. code-block:: c | |
239 | ||
240 | #ifdef LIBGCCJIT_HAVE_TIMING_API |