proc.c revision 283010 
1/* Copyright (C) 2007 Free Software Foundation, Inc.
2   Contributed by Danny Smith <dannysmith@users.sourceforge.net>
3
4   This file is part of the GNU OpenMP Library (libgomp).
5
6   Libgomp is free software; you can redistribute it and/or modify it
7   under the terms of the GNU Lesser General Public License as published by
8   the Free Software Foundation; either version 2.1 of the License, or
9   (at your option) any later version.
10
11   Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
12   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
13   FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for
14   more details.
15
16   You should have received a copy of the GNU Lesser General Public License
17   along with libgomp; see the file COPYING.LIB.  If not, write to the
18   Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
19   MA 02110-1301, USA.  */
20
21/* As a special exception, if you link this library with other files, some
22   of which are compiled with GCC, to produce an executable, this library
23   does not by itself cause the resulting executable to be covered by the
24   GNU General Public License.  This exception does not however invalidate
25   any other reasons why the executable file might be covered by the GNU
26   General Public License.  */
27
28/* This file contains system specific routines related to counting
29   online processors and dynamic load balancing.  It is expected that
30   a system may well want to write special versions of each of these.
31
32   The following implementation uses win32 API routines.  */
33
34#include "libgomp.h"
35#include <windows.h>
36
37/* Count the CPU's currently available to this process.  */
38static int
39count_avail_process_cpus ()
40{
41  DWORD_PTR process_cpus;
42  DWORD_PTR system_cpus;
43
44  if (GetProcessAffinityMask (GetCurrentProcess (),
45			      &process_cpus, &system_cpus))
46    {
47      unsigned int count;
48      for (count = 0; process_cpus != 0; process_cpus >>= 1)
49	if (process_cpus & 1)
50	  count++;
51      return count;
52    }
53  return 1;
54}
55
56/* At startup, determine the default number of threads.  It would seem
57   this should be related to the number of cpus available to the process.  */
58
59void
60gomp_init_num_threads (void)
61{
62  gomp_nthreads_var = count_avail_process_cpus ();
63}
64
65/* When OMP_DYNAMIC is set, at thread launch determine the number of
66   threads we should spawn for this team.  FIXME:  How do we adjust for
67   load average on MS Windows?  */
68
69unsigned
70gomp_dynamic_max_threads (void)
71{
72  int n_onln = count_avail_process_cpus ();
73  return n_onln > gomp_nthreads_var ? gomp_nthreads_var : n_onln;
74}
75
76int
77omp_get_num_procs (void)
78{
79  return count_avail_process_cpus ();
80}
81
82ialias (omp_get_num_procs)
83