proc.c: New file.

[thirdparty/gcc.git] / libgomp / config / bsd / proc.c

diff --git a/libgomp/config/bsd/proc.c b/libgomp/config/bsd/proc.c
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+/* Copyright (C) 2005, 2006, 2008 Free Software Foundation, Inc.
+   Contributed by Richard Henderson <rth@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 Lesser General Public License as published by
+   the Free Software Foundation; either version 2.1 of the License, 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 Lesser General Public License for
+   more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with libgomp; see the file COPYING.LIB.  If not, write to the
+   Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+   MA 02110-1301, USA.  */
+
+/* As a special exception, if you link this library with other files, some
+   of which are compiled with GCC, to produce an executable, this library
+   does not by itself cause the resulting executable to be covered by the
+   GNU General Public License.  This exception does not however invalidate
+   any other reasons why the executable file might be covered by the GNU
+   General Public License.  */
+
+/* This file contains system specific routines related to counting
+   online processors and dynamic load balancing.  It is expected that
+   a system may well want to write special versions of each of these.
+
+   The following implementation uses a mix of POSIX and BSD routines.  */
+
+#include "libgomp.h"
+#include <unistd.h>
+#include <stdlib.h>
+#ifdef HAVE_GETLOADAVG
+# ifdef HAVE_SYS_LOADAVG_H
+#  include <sys/loadavg.h>
+# endif
+#endif
+#ifdef HAVE_SYS_SYSCTL_H
+# include <sys/sysctl.h>
+#endif
+
+static int
+get_num_procs (void)
+{
+#ifdef _SC_NPROCESSORS_ONLN
+  return sysconf (_SC_NPROCESSORS_ONLN);
+#elif defined HW_NCPU
+  int ncpus = 1;
+  size_t len = sizeof(ncpus);
+  sysctl((int[2]) {CTL_HW, HW_NCPU}, 2, &ncpus, &len, NULL, 0);
+  return ncpus;
+#else
+  return 0;
+#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)
+{
+  int ncpus = get_num_procs ();
+
+  if (ncpus > 0)
+    gomp_global_icv.nthreads_var = ncpus;
+}
+
+/* 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;
+  unsigned nthreads_var = gomp_icv (false)->nthreads_var;
+
+  n_onln = get_num_procs ();
+  if (!n_onln || 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)
+{
+  int ncpus = get_num_procs ();
+  if (ncpus <= 0)
+    ncpus = gomp_icv (false)->nthreads_var;
+  return ncpus;
+}
+
+ialias (omp_get_num_procs)