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authorupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
committerupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
commit554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree976dc5ab7fddf506dadce60ae936f43f58787092 /libgomp/config/linux/proc.c
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diff --git a/libgomp/config/linux/proc.c b/libgomp/config/linux/proc.c
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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)