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[/] [openrisc/] [trunk/] [gnu-src/] [gcc-4.5.1/] [libgomp/] [config/] [linux/] [proc.c] - Rev 280
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/* Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc. Contributed by Jakub Jelinek <jakub@redhat.com>. This file is part of the GNU OpenMP Library (libgomp). Libgomp is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. Under Section 7 of GPL version 3, you are granted additional permissions described in the GCC Runtime Library Exception, version 3.1, as published by the Free Software Foundation. You should have received a copy of the GNU General Public License and a copy of the GCC Runtime Library Exception along with this program; see the files COPYING3 and COPYING.RUNTIME respectively. If not, see <http://www.gnu.org/licenses/>. */ /* This file contains system specific routines related to counting online processors and dynamic load balancing. */ #ifndef _GNU_SOURCE #define _GNU_SOURCE 1 #endif #include "libgomp.h" #include <sched.h> #include <stdlib.h> #include <unistd.h> #ifdef HAVE_GETLOADAVG # ifdef HAVE_SYS_LOADAVG_H # include <sys/loadavg.h> # endif #endif #ifdef HAVE_PTHREAD_AFFINITY_NP static unsigned long cpuset_popcount (cpu_set_t *cpusetp) { #ifdef CPU_COUNT /* glibc 2.6 and above provide a macro for this. */ return CPU_COUNT (cpusetp); #else size_t i; unsigned long ret = 0; extern int check[sizeof (cpusetp->__bits[0]) == sizeof (unsigned long int)]; (void) check; for (i = 0; i < sizeof (*cpusetp) / sizeof (cpusetp->__bits[0]); i++) { unsigned long int mask = cpusetp->__bits[i]; if (mask == 0) continue; ret += __builtin_popcountl (mask); } return ret; #endif } #endif /* At startup, determine the default number of threads. It would seem this should be related to the number of cpus online. */ void gomp_init_num_threads (void) { #ifdef HAVE_PTHREAD_AFFINITY_NP cpu_set_t cpuset; if (pthread_getaffinity_np (pthread_self (), sizeof (cpuset), &cpuset) == 0) { /* Count only the CPUs this process can use. */ gomp_global_icv.nthreads_var = cpuset_popcount (&cpuset); if (gomp_global_icv.nthreads_var == 0) gomp_global_icv.nthreads_var = 1; return; } #endif #ifdef _SC_NPROCESSORS_ONLN gomp_global_icv.nthreads_var = sysconf (_SC_NPROCESSORS_ONLN); #endif } static int get_num_procs (void) { #ifdef HAVE_PTHREAD_AFFINITY_NP cpu_set_t cpuset; if (gomp_cpu_affinity == NULL) { /* Count only the CPUs this process can use. */ if (pthread_getaffinity_np (pthread_self (), sizeof (cpuset), &cpuset) == 0) { int ret = cpuset_popcount (&cpuset); return ret != 0 ? ret : 1; } } else { /* We can't use pthread_getaffinity_np in this case (we have changed it ourselves, it binds to just one CPU). Count instead the number of different CPUs we are using. gomp_init_affinity updated gomp_available_cpus to the number of CPUs in the GOMP_AFFINITY mask that we are allowed to use though. */ return gomp_available_cpus; } #endif #ifdef _SC_NPROCESSORS_ONLN return sysconf (_SC_NPROCESSORS_ONLN); #else return gomp_icv (false)->nthreads_var; #endif } /* When OMP_DYNAMIC is set, at thread launch determine the number of threads we should spawn for this team. */ /* ??? I have no idea what best practice for this is. Surely some function of the number of processors that are *still* online and the load average. Here I use the number of processors online minus the 15 minute load average. */ unsigned gomp_dynamic_max_threads (void) { unsigned n_onln, loadavg, nthreads_var = gomp_icv (false)->nthreads_var; n_onln = get_num_procs (); if (n_onln > nthreads_var) n_onln = nthreads_var; loadavg = 0; #ifdef HAVE_GETLOADAVG { double dloadavg[3]; if (getloadavg (dloadavg, 3) == 3) { /* Add 0.1 to get a kind of biased rounding. */ loadavg = dloadavg[2] + 0.1; } } #endif if (loadavg >= n_onln) return 1; else return n_onln - loadavg; } int omp_get_num_procs (void) { return get_num_procs (); } ialias (omp_get_num_procs)
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