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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgomp/] [config/] [linux/] [proc.c] - Blame information for rev 735

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1 735 jeremybenn
/* Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
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   Free Software Foundation, Inc.
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   Contributed by Jakub Jelinek <jakub@redhat.com>.
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   This file is part of the GNU OpenMP Library (libgomp).
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   Libgomp is free software; you can redistribute it and/or modify it
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   under the terms of the GNU General Public License as published by
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   the Free Software Foundation; either version 3, or (at your option)
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   any later version.
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   Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
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   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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   FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
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   more details.
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   Under Section 7 of GPL version 3, you are granted additional
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   permissions described in the GCC Runtime Library Exception, version
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   3.1, as published by the Free Software Foundation.
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   You should have received a copy of the GNU General Public License and
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   a copy of the GCC Runtime Library Exception along with this program;
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   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
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   <http://www.gnu.org/licenses/>.  */
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/* This file contains system specific routines related to counting
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   online processors and dynamic load balancing.  */
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#ifndef _GNU_SOURCE
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#define _GNU_SOURCE 1
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#endif
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#include "libgomp.h"
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#include "proc.h"
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#include <stdlib.h>
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#include <unistd.h>
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#ifdef HAVE_GETLOADAVG
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# ifdef HAVE_SYS_LOADAVG_H
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#  include <sys/loadavg.h>
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# endif
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#endif
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#ifdef HAVE_PTHREAD_AFFINITY_NP
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unsigned long
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gomp_cpuset_popcount (cpu_set_t *cpusetp)
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{
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#ifdef CPU_COUNT
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  /* glibc 2.6 and above provide a macro for this.  */
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  return CPU_COUNT (cpusetp);
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#else
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  size_t i;
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  unsigned long ret = 0;
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  extern int check[sizeof (cpusetp->__bits[0]) == sizeof (unsigned long int)];
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  (void) check;
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  for (i = 0; i < sizeof (*cpusetp) / sizeof (cpusetp->__bits[0]); i++)
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    {
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      unsigned long int mask = cpusetp->__bits[i];
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      if (mask == 0)
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        continue;
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      ret += __builtin_popcountl (mask);
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    }
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  return ret;
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#endif
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}
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#endif
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/* At startup, determine the default number of threads.  It would seem
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   this should be related to the number of cpus online.  */
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void
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gomp_init_num_threads (void)
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{
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#ifdef HAVE_PTHREAD_AFFINITY_NP
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  cpu_set_t cpuset;
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  if (pthread_getaffinity_np (pthread_self (), sizeof (cpuset), &cpuset) == 0)
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    {
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      /* Count only the CPUs this process can use.  */
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      gomp_global_icv.nthreads_var = gomp_cpuset_popcount (&cpuset);
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      if (gomp_global_icv.nthreads_var == 0)
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        gomp_global_icv.nthreads_var = 1;
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      return;
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    }
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#endif
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#ifdef _SC_NPROCESSORS_ONLN
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  gomp_global_icv.nthreads_var = sysconf (_SC_NPROCESSORS_ONLN);
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#endif
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}
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static int
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get_num_procs (void)
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{
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#ifdef HAVE_PTHREAD_AFFINITY_NP
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  cpu_set_t cpuset;
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  if (gomp_cpu_affinity == NULL)
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    {
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      /* Count only the CPUs this process can use.  */
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      if (pthread_getaffinity_np (pthread_self (), sizeof (cpuset),
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                                  &cpuset) == 0)
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        {
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          int ret = gomp_cpuset_popcount (&cpuset);
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          return ret != 0 ? ret : 1;
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        }
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    }
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  else
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    {
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      /* We can't use pthread_getaffinity_np in this case
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         (we have changed it ourselves, it binds to just one CPU).
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         Count instead the number of different CPUs we are
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         using.  gomp_init_affinity updated gomp_available_cpus to
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         the number of CPUs in the GOMP_AFFINITY mask that we are
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         allowed to use though.  */
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      return gomp_available_cpus;
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    }
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#endif
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#ifdef _SC_NPROCESSORS_ONLN
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  return sysconf (_SC_NPROCESSORS_ONLN);
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#else
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  return gomp_icv (false)->nthreads_var;
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#endif
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}
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/* When OMP_DYNAMIC is set, at thread launch determine the number of
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   threads we should spawn for this team.  */
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/* ??? I have no idea what best practice for this is.  Surely some
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   function of the number of processors that are *still* online and
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   the load average.  Here I use the number of processors online
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   minus the 15 minute load average.  */
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unsigned
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gomp_dynamic_max_threads (void)
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{
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  unsigned n_onln, loadavg, nthreads_var = gomp_icv (false)->nthreads_var;
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  n_onln = get_num_procs ();
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  if (n_onln > nthreads_var)
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    n_onln = nthreads_var;
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  loadavg = 0;
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#ifdef HAVE_GETLOADAVG
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  {
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    double dloadavg[3];
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    if (getloadavg (dloadavg, 3) == 3)
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      {
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        /* Add 0.1 to get a kind of biased rounding.  */
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        loadavg = dloadavg[2] + 0.1;
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      }
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  }
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#endif
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  if (loadavg >= n_onln)
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    return 1;
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  else
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    return n_onln - loadavg;
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}
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int
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omp_get_num_procs (void)
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{
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  return get_num_procs ();
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}
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ialias (omp_get_num_procs)

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