1 /*
2 * ptw32_getprocessors.c
3 *
4 * Description:
5 * This translation unit implements routines which are private to
6 * the implementation and may be used throughout it.
7 *
8 * --------------------------------------------------------------------------
9 *
10 * Pthreads-win32 - POSIX Threads Library for Win32
11 * Copyright(C) 1998 John E. Bossom
12 * Copyright(C) 1999,2005 Pthreads-win32 contributors
13 *
14 * Contact Email: rpj@callisto.canberra.edu.au
15 *
16 * The current list of contributors is contained
17 * in the file CONTRIBUTORS included with the source
18 * code distribution. The list can also be seen at the
19 * following World Wide Web location:
20 * http://sources.redhat.com/pthreads-win32/contributors.html
21 *
22 * This library is free software; you can redistribute it and/or
23 * modify it under the terms of the GNU Lesser General Public
24 * License as published by the Free Software Foundation; either
25 * version 2 of the License, or (at your option) any later version.
26 *
27 * This library is distributed in the hope that it will be useful,
28 * but WITHOUT ANY WARRANTY; without even the implied warranty of
29 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
30 * Lesser General Public License for more details.
31 *
32 * You should have received a copy of the GNU Lesser General Public
33 * License along with this library in the file COPYING.LIB;
34 * if not, write to the Free Software Foundation, Inc.,
35 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
36 */
37
38 #include "pthread.h"
39 #include "implement.h"
40
41
42 /*
43 * ptw32_getprocessors()
44 *
45 * Get the number of CPUs available to the process.
46 *
47 * If the available number of CPUs is 1 then pthread_spin_lock()
48 * will block rather than spin if the lock is already owned.
49 *
50 * pthread_spin_init() calls this routine when initialising
51 * a spinlock. If the number of available processors changes
52 * (after a call to SetProcessAffinityMask()) then only
53 * newly initialised spinlocks will notice.
54 */
55 int
ptw32_getprocessors(int * count)56 ptw32_getprocessors (int *count)
57 {
58 DWORD_PTR vProcessCPUs;
59 DWORD_PTR vSystemCPUs;
60 int result = 0;
61
62 #if defined(NEED_PROCESS_AFFINITY_MASK)
63
64 *count = 1;
65
66 #else
67
68 if (GetProcessAffinityMask (GetCurrentProcess (),
69 &vProcessCPUs, &vSystemCPUs))
70 {
71 DWORD_PTR bit;
72 int CPUs = 0;
73
74 for (bit = 1; bit != 0; bit <<= 1)
75 {
76 if (vProcessCPUs & bit)
77 {
78 CPUs++;
79 }
80 }
81 *count = CPUs;
82 }
83 else
84 {
85 result = EAGAIN;
86 }
87
88 #endif
89
90 return (result);
91 }
92