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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libgomp/config/linux/proc.c | |
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Diffstat (limited to 'libgomp/config/linux/proc.c')
-rw-r--r-- | libgomp/config/linux/proc.c | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/libgomp/config/linux/proc.c b/libgomp/config/linux/proc.c new file mode 100644 index 000000000..01f51dfa1 --- /dev/null +++ b/libgomp/config/linux/proc.c @@ -0,0 +1,164 @@ +/* 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) |