/* Detect the number of processors.
- Copyright (C) 2009 Free Software Foundation, Inc.
+ Copyright (C) 2009-2014 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software Foundation,
- Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+ along with this program; if not, see <http://www.gnu.org/licenses/>. */
-/* Written by Glen Lenker. */
+/* Written by Glen Lenker and Bruno Haible. */
#include <config.h>
#include "nproc.h"
+#include <stdlib.h>
#include <unistd.h>
+#if HAVE_PTHREAD_GETAFFINITY_NP && 0
+# include <pthread.h>
+# include <sched.h>
+#endif
+#if HAVE_SCHED_GETAFFINITY_LIKE_GLIBC || HAVE_SCHED_GETAFFINITY_NP
+# include <sched.h>
+#endif
+
#include <sys/types.h>
#if HAVE_SYS_PSTAT_H
# include <sys/sysctl.h>
#endif
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+#endif
+
+#include "c-ctype.h"
+
#define ARRAY_SIZE(a) (sizeof (a) / sizeof ((a)[0]))
-/* Return the total number of processors. The result is guaranteed to
- be at least 1. */
+/* Return the number of processors available to the current process, based
+ on a modern system call that returns the "affinity" between the current
+ process and each CPU. Return 0 if unknown or if such a system call does
+ not exist. */
+static unsigned long
+num_processors_via_affinity_mask (void)
+{
+ /* glibc >= 2.3.3 with NPTL and NetBSD 5 have pthread_getaffinity_np,
+ but with different APIs. Also it requires linking with -lpthread.
+ Therefore this code is not enabled.
+ glibc >= 2.3.4 has sched_getaffinity whereas NetBSD 5 has
+ sched_getaffinity_np. */
+#if HAVE_PTHREAD_GETAFFINITY_NP && defined __GLIBC__ && 0
+ {
+ cpu_set_t set;
+
+ if (pthread_getaffinity_np (pthread_self (), sizeof (set), &set) == 0)
+ {
+ unsigned long count;
+
+# ifdef CPU_COUNT
+ /* glibc >= 2.6 has the CPU_COUNT macro. */
+ count = CPU_COUNT (&set);
+# else
+ size_t i;
+
+ count = 0;
+ for (i = 0; i < CPU_SETSIZE; i++)
+ if (CPU_ISSET (i, &set))
+ count++;
+# endif
+ if (count > 0)
+ return count;
+ }
+ }
+#elif HAVE_PTHREAD_GETAFFINITY_NP && defined __NetBSD__ && 0
+ {
+ cpuset_t *set;
+
+ set = cpuset_create ();
+ if (set != NULL)
+ {
+ unsigned long count = 0;
+
+ if (pthread_getaffinity_np (pthread_self (), cpuset_size (set), set)
+ == 0)
+ {
+ cpuid_t i;
+
+ for (i = 0;; i++)
+ {
+ int ret = cpuset_isset (i, set);
+ if (ret < 0)
+ break;
+ if (ret > 0)
+ count++;
+ }
+ }
+ cpuset_destroy (set);
+ if (count > 0)
+ return count;
+ }
+ }
+#elif HAVE_SCHED_GETAFFINITY_LIKE_GLIBC /* glibc >= 2.3.4 */
+ {
+ cpu_set_t set;
+
+ if (sched_getaffinity (0, sizeof (set), &set) == 0)
+ {
+ unsigned long count;
+
+# ifdef CPU_COUNT
+ /* glibc >= 2.6 has the CPU_COUNT macro. */
+ count = CPU_COUNT (&set);
+# else
+ size_t i;
+
+ count = 0;
+ for (i = 0; i < CPU_SETSIZE; i++)
+ if (CPU_ISSET (i, &set))
+ count++;
+# endif
+ if (count > 0)
+ return count;
+ }
+ }
+#elif HAVE_SCHED_GETAFFINITY_NP /* NetBSD >= 5 */
+ {
+ cpuset_t *set;
+
+ set = cpuset_create ();
+ if (set != NULL)
+ {
+ unsigned long count = 0;
+
+ if (sched_getaffinity_np (getpid (), cpuset_size (set), set) == 0)
+ {
+ cpuid_t i;
+
+ for (i = 0;; i++)
+ {
+ int ret = cpuset_isset (i, set);
+ if (ret < 0)
+ break;
+ if (ret > 0)
+ count++;
+ }
+ }
+ cpuset_destroy (set);
+ if (count > 0)
+ return count;
+ }
+ }
+#endif
+
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+ { /* This works on native Windows platforms. */
+ DWORD_PTR process_mask;
+ DWORD_PTR system_mask;
+
+ if (GetProcessAffinityMask (GetCurrentProcess (),
+ &process_mask, &system_mask))
+ {
+ DWORD_PTR mask = process_mask;
+ unsigned long count = 0;
+
+ for (; mask != 0; mask = mask >> 1)
+ if (mask & 1)
+ count++;
+ if (count > 0)
+ return count;
+ }
+ }
+#endif
+
+ return 0;
+}
+
unsigned long int
-num_processors (void)
+num_processors (enum nproc_query query)
{
+ if (query == NPROC_CURRENT_OVERRIDABLE)
+ {
+ /* Test the environment variable OMP_NUM_THREADS, recognized also by all
+ programs that are based on OpenMP. The OpenMP spec says that the
+ value assigned to the environment variable "may have leading and
+ trailing white space". */
+ const char *envvalue = getenv ("OMP_NUM_THREADS");
+
+ if (envvalue != NULL)
+ {
+ while (*envvalue != '\0' && c_isspace (*envvalue))
+ envvalue++;
+ /* Convert it from decimal to 'unsigned long'. */
+ if (c_isdigit (*envvalue))
+ {
+ char *endptr = NULL;
+ unsigned long int value = strtoul (envvalue, &endptr, 10);
+
+ if (endptr != NULL)
+ {
+ while (*endptr != '\0' && c_isspace (*endptr))
+ endptr++;
+ if (*endptr == '\0')
+ return (value > 0 ? value : 1);
+ }
+ }
+ }
+
+ query = NPROC_CURRENT;
+ }
+ /* Here query is one of NPROC_ALL, NPROC_CURRENT. */
+
+ /* On systems with a modern affinity mask system call, we have
+ sysconf (_SC_NPROCESSORS_CONF)
+ >= sysconf (_SC_NPROCESSORS_ONLN)
+ >= num_processors_via_affinity_mask ()
+ The first number is the number of CPUs configured in the system.
+ The second number is the number of CPUs available to the scheduler.
+ The third number is the number of CPUs available to the current process.
+
+ Note! On Linux systems with glibc, the first and second number come from
+ the /sys and /proc file systems (see
+ glibc/sysdeps/unix/sysv/linux/getsysstats.c).
+ In some situations these file systems are not mounted, and the sysconf
+ call returns 1, which does not reflect the reality. */
+
+ if (query == NPROC_CURRENT)
+ {
+ /* Try the modern affinity mask system call. */
+ {
+ unsigned long nprocs = num_processors_via_affinity_mask ();
+
+ if (nprocs > 0)
+ return nprocs;
+ }
+
#if defined _SC_NPROCESSORS_ONLN
- { /* This works on glibc, MacOS X 10.5, FreeBSD, AIX, OSF/1, Solaris, Cygwin,
- Haiku. */
- long int nprocs = sysconf (_SC_NPROCESSORS_ONLN);
- if (0 < nprocs)
- return nprocs;
- }
+ { /* This works on glibc, Mac OS X 10.5, FreeBSD, AIX, OSF/1, Solaris,
+ Cygwin, Haiku. */
+ long int nprocs = sysconf (_SC_NPROCESSORS_ONLN);
+ if (nprocs > 0)
+ return nprocs;
+ }
+#endif
+ }
+ else /* query == NPROC_ALL */
+ {
+#if defined _SC_NPROCESSORS_CONF
+ { /* This works on glibc, Mac OS X 10.5, FreeBSD, AIX, OSF/1, Solaris,
+ Cygwin, Haiku. */
+ long int nprocs = sysconf (_SC_NPROCESSORS_CONF);
+
+# if __GLIBC__ >= 2 && defined __linux__
+ /* On Linux systems with glibc, this information comes from the /sys and
+ /proc file systems (see glibc/sysdeps/unix/sysv/linux/getsysstats.c).
+ In some situations these file systems are not mounted, and the
+ sysconf call returns 1. But we wish to guarantee that
+ num_processors (NPROC_ALL) >= num_processors (NPROC_CURRENT). */
+ if (nprocs == 1)
+ {
+ unsigned long nprocs_current = num_processors_via_affinity_mask ();
+
+ if (nprocs_current > 0)
+ nprocs = nprocs_current;
+ }
+# endif
+
+ if (nprocs > 0)
+ return nprocs;
+ }
#endif
+ }
#if HAVE_PSTAT_GETDYNAMIC
{ /* This works on HP-UX. */
struct pst_dynamic psd;
- if (0 <= pstat_getdynamic (&psd, sizeof psd, 1, 0)
- && 0 < psd.psd_proc_cnt)
- return psd.psd_proc_cnt;
+ if (pstat_getdynamic (&psd, sizeof psd, 1, 0) >= 0)
+ {
+ /* The field psd_proc_cnt contains the number of active processors.
+ In newer releases of HP-UX 11, the field psd_max_proc_cnt includes
+ deactivated processors. */
+ if (query == NPROC_CURRENT)
+ {
+ if (psd.psd_proc_cnt > 0)
+ return psd.psd_proc_cnt;
+ }
+ else
+ {
+ if (psd.psd_max_proc_cnt > 0)
+ return psd.psd_max_proc_cnt;
+ }
+ }
}
#endif
-#if HAVE_SYSMP && defined MP_NAPROCS
+#if HAVE_SYSMP && defined MP_NAPROCS && defined MP_NPROCS
{ /* This works on IRIX. */
/* MP_NPROCS yields the number of installed processors.
MP_NAPROCS yields the number of processors available to unprivileged
- processes. We need the latter. */
- int nprocs = sysmp (MP_NAPROCS);
- if (0 < nprocs)
+ processes. */
+ int nprocs =
+ sysmp (query == NPROC_CURRENT && getpid () != 0
+ ? MP_NAPROCS
+ : MP_NPROCS);
+ if (nprocs > 0)
return nprocs;
}
#endif
+ /* Finally, as fallback, use the APIs that don't distinguish between
+ NPROC_CURRENT and NPROC_ALL. */
+
#if HAVE_SYSCTL && defined HW_NCPU
- { /* This works on MacOS X, FreeBSD, NetBSD, OpenBSD. */
+ { /* This works on Mac OS X, FreeBSD, NetBSD, OpenBSD. */
int nprocs;
size_t len = sizeof (nprocs);
static int mib[2] = { CTL_HW, HW_NCPU };
if (sysctl (mib, ARRAY_SIZE (mib), &nprocs, &len, NULL, 0) == 0
- && len == sizeof (nprocs)
- && 0 < nprocs)
+ && len == sizeof (nprocs)
+ && 0 < nprocs)
return nprocs;
}
#endif
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+ { /* This works on native Windows platforms. */
+ SYSTEM_INFO system_info;
+ GetSystemInfo (&system_info);
+ if (0 < system_info.dwNumberOfProcessors)
+ return system_info.dwNumberOfProcessors;
+ }
+#endif
+
return 1;
}
projects / gnulib.git / blobdiff