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f1717362 | 1 | /* Copyright (C) 2005-2016 Free Software Foundation, Inc. |
1e8e9920 | 2 | Contributed by Richard Henderson <rth@redhat.com>. |
3 | ||
c35c9a62 | 4 | This file is part of the GNU Offloading and Multi Processing Library |
5 | (libgomp). | |
1e8e9920 | 6 | |
7 | Libgomp is free software; you can redistribute it and/or modify it | |
6bc9506f | 8 | under the terms of the GNU General Public License as published by |
9 | the Free Software Foundation; either version 3, or (at your option) | |
10 | any later version. | |
1e8e9920 | 11 | |
12 | Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY | |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS | |
6bc9506f | 14 | FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
1e8e9920 | 15 | more details. |
16 | ||
6bc9506f | 17 | Under Section 7 of GPL version 3, you are granted additional |
18 | permissions described in the GCC Runtime Library Exception, version | |
19 | 3.1, as published by the Free Software Foundation. | |
20 | ||
21 | You should have received a copy of the GNU General Public License and | |
22 | a copy of the GCC Runtime Library Exception along with this program; | |
23 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
24 | <http://www.gnu.org/licenses/>. */ | |
1e8e9920 | 25 | |
26 | /* This file contains system specific routines related to counting | |
27 | online processors and dynamic load balancing. It is expected that | |
28 | a system may well want to write special versions of each of these. | |
29 | ||
30 | The following implementation uses a mix of POSIX and BSD routines. */ | |
31 | ||
32 | #include "libgomp.h" | |
33 | #include <unistd.h> | |
34 | #include <stdlib.h> | |
138f59be | 35 | #ifdef HAVE_GETLOADAVG |
36 | # ifdef HAVE_SYS_LOADAVG_H | |
37 | # include <sys/loadavg.h> | |
38 | # endif | |
39 | #endif | |
1e8e9920 | 40 | |
41 | ||
42 | /* At startup, determine the default number of threads. It would seem | |
43 | this should be related to the number of cpus online. */ | |
44 | ||
45 | void | |
46 | gomp_init_num_threads (void) | |
47 | { | |
48 | #ifdef _SC_NPROCESSORS_ONLN | |
fd6481cf | 49 | gomp_global_icv.nthreads_var = sysconf (_SC_NPROCESSORS_ONLN); |
1e8e9920 | 50 | #endif |
51 | } | |
52 | ||
53 | /* When OMP_DYNAMIC is set, at thread launch determine the number of | |
54 | threads we should spawn for this team. */ | |
55 | /* ??? I have no idea what best practice for this is. Surely some | |
56 | function of the number of processors that are *still* online and | |
57 | the load average. Here I use the number of processors online | |
58 | minus the 15 minute load average. */ | |
59 | ||
60 | unsigned | |
61 | gomp_dynamic_max_threads (void) | |
62 | { | |
63 | unsigned n_onln, loadavg; | |
fd6481cf | 64 | unsigned nthreads_var = gomp_icv (false)->nthreads_var; |
1e8e9920 | 65 | |
66 | #ifdef _SC_NPROCESSORS_ONLN | |
67 | n_onln = sysconf (_SC_NPROCESSORS_ONLN); | |
fd6481cf | 68 | if (n_onln > nthreads_var) |
69 | n_onln = nthreads_var; | |
1e8e9920 | 70 | #else |
fd6481cf | 71 | n_onln = nthreads_var; |
1e8e9920 | 72 | #endif |
73 | ||
74 | loadavg = 0; | |
75 | #ifdef HAVE_GETLOADAVG | |
76 | { | |
77 | double dloadavg[3]; | |
78 | if (getloadavg (dloadavg, 3) == 3) | |
79 | { | |
80 | /* Add 0.1 to get a kind of biased rounding. */ | |
81 | loadavg = dloadavg[2] + 0.1; | |
82 | } | |
83 | } | |
84 | #endif | |
85 | ||
86 | if (loadavg >= n_onln) | |
87 | return 1; | |
88 | else | |
89 | return n_onln - loadavg; | |
90 | } | |
91 | ||
92 | int | |
93 | omp_get_num_procs (void) | |
94 | { | |
95 | #ifdef _SC_NPROCESSORS_ONLN | |
96 | return sysconf (_SC_NPROCESSORS_ONLN); | |
97 | #else | |
fd6481cf | 98 | return gomp_icv (false)->nthreads_var; |
1e8e9920 | 99 | #endif |
100 | } | |
101 | ||
102 | ialias (omp_get_num_procs) |