1*629ff9f7SJohn Marino /* Copyright (C) 2005, 2006, 2008, 2009 Free Software Foundation, Inc.
2*629ff9f7SJohn Marino Contributed by Richard Henderson <rth@redhat.com>.
3*629ff9f7SJohn Marino
4*629ff9f7SJohn Marino This file is part of the GNU OpenMP Library (libgomp).
5*629ff9f7SJohn Marino
6*629ff9f7SJohn Marino Libgomp is free software; you can redistribute it and/or modify it
7*629ff9f7SJohn Marino under the terms of the GNU General Public License as published by
8*629ff9f7SJohn Marino the Free Software Foundation; either version 3, or (at your option)
9*629ff9f7SJohn Marino any later version.
10*629ff9f7SJohn Marino
11*629ff9f7SJohn Marino Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
12*629ff9f7SJohn Marino WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
13*629ff9f7SJohn Marino FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14*629ff9f7SJohn Marino more details.
15*629ff9f7SJohn Marino
16*629ff9f7SJohn Marino Under Section 7 of GPL version 3, you are granted additional
17*629ff9f7SJohn Marino permissions described in the GCC Runtime Library Exception, version
18*629ff9f7SJohn Marino 3.1, as published by the Free Software Foundation.
19*629ff9f7SJohn Marino
20*629ff9f7SJohn Marino You should have received a copy of the GNU General Public License and
21*629ff9f7SJohn Marino a copy of the GCC Runtime Library Exception along with this program;
22*629ff9f7SJohn Marino see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23*629ff9f7SJohn Marino <http://www.gnu.org/licenses/>. */
24*629ff9f7SJohn Marino
25*629ff9f7SJohn Marino /* This file contains system specific routines related to counting
26*629ff9f7SJohn Marino online processors and dynamic load balancing. It is expected that
27*629ff9f7SJohn Marino a system may well want to write special versions of each of these.
28*629ff9f7SJohn Marino
29*629ff9f7SJohn Marino The following implementation uses a mix of POSIX and BSD routines. */
30*629ff9f7SJohn Marino
31*629ff9f7SJohn Marino #include "libgomp.h"
32*629ff9f7SJohn Marino #include <unistd.h>
33*629ff9f7SJohn Marino #include <stdlib.h>
34*629ff9f7SJohn Marino #ifdef HAVE_GETLOADAVG
35*629ff9f7SJohn Marino # ifdef HAVE_SYS_LOADAVG_H
36*629ff9f7SJohn Marino # include <sys/loadavg.h>
37*629ff9f7SJohn Marino # endif
38*629ff9f7SJohn Marino #endif
39*629ff9f7SJohn Marino
40*629ff9f7SJohn Marino
41*629ff9f7SJohn Marino /* At startup, determine the default number of threads. It would seem
42*629ff9f7SJohn Marino this should be related to the number of cpus online. */
43*629ff9f7SJohn Marino
44*629ff9f7SJohn Marino void
gomp_init_num_threads(void)45*629ff9f7SJohn Marino gomp_init_num_threads (void)
46*629ff9f7SJohn Marino {
47*629ff9f7SJohn Marino #ifdef _SC_NPROCESSORS_ONLN
48*629ff9f7SJohn Marino gomp_global_icv.nthreads_var = sysconf (_SC_NPROCESSORS_ONLN);
49*629ff9f7SJohn Marino #endif
50*629ff9f7SJohn Marino }
51*629ff9f7SJohn Marino
52*629ff9f7SJohn Marino /* When OMP_DYNAMIC is set, at thread launch determine the number of
53*629ff9f7SJohn Marino threads we should spawn for this team. */
54*629ff9f7SJohn Marino /* ??? I have no idea what best practice for this is. Surely some
55*629ff9f7SJohn Marino function of the number of processors that are *still* online and
56*629ff9f7SJohn Marino the load average. Here I use the number of processors online
57*629ff9f7SJohn Marino minus the 15 minute load average. */
58*629ff9f7SJohn Marino
59*629ff9f7SJohn Marino unsigned
gomp_dynamic_max_threads(void)60*629ff9f7SJohn Marino gomp_dynamic_max_threads (void)
61*629ff9f7SJohn Marino {
62*629ff9f7SJohn Marino unsigned n_onln, loadavg;
63*629ff9f7SJohn Marino unsigned nthreads_var = gomp_icv (false)->nthreads_var;
64*629ff9f7SJohn Marino
65*629ff9f7SJohn Marino #ifdef _SC_NPROCESSORS_ONLN
66*629ff9f7SJohn Marino n_onln = sysconf (_SC_NPROCESSORS_ONLN);
67*629ff9f7SJohn Marino if (n_onln > nthreads_var)
68*629ff9f7SJohn Marino n_onln = nthreads_var;
69*629ff9f7SJohn Marino #else
70*629ff9f7SJohn Marino n_onln = nthreads_var;
71*629ff9f7SJohn Marino #endif
72*629ff9f7SJohn Marino
73*629ff9f7SJohn Marino loadavg = 0;
74*629ff9f7SJohn Marino #ifdef HAVE_GETLOADAVG
75*629ff9f7SJohn Marino {
76*629ff9f7SJohn Marino double dloadavg[3];
77*629ff9f7SJohn Marino if (getloadavg (dloadavg, 3) == 3)
78*629ff9f7SJohn Marino {
79*629ff9f7SJohn Marino /* Add 0.1 to get a kind of biased rounding. */
80*629ff9f7SJohn Marino loadavg = dloadavg[2] + 0.1;
81*629ff9f7SJohn Marino }
82*629ff9f7SJohn Marino }
83*629ff9f7SJohn Marino #endif
84*629ff9f7SJohn Marino
85*629ff9f7SJohn Marino if (loadavg >= n_onln)
86*629ff9f7SJohn Marino return 1;
87*629ff9f7SJohn Marino else
88*629ff9f7SJohn Marino return n_onln - loadavg;
89*629ff9f7SJohn Marino }
90*629ff9f7SJohn Marino
91*629ff9f7SJohn Marino int
omp_get_num_procs(void)92*629ff9f7SJohn Marino omp_get_num_procs (void)
93*629ff9f7SJohn Marino {
94*629ff9f7SJohn Marino #ifdef _SC_NPROCESSORS_ONLN
95*629ff9f7SJohn Marino return sysconf (_SC_NPROCESSORS_ONLN);
96*629ff9f7SJohn Marino #else
97*629ff9f7SJohn Marino return gomp_icv (false)->nthreads_var;
98*629ff9f7SJohn Marino #endif
99*629ff9f7SJohn Marino }
100*629ff9f7SJohn Marino
101*629ff9f7SJohn Marino ialias (omp_get_num_procs)
102