X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fnproc.c;h=7ebf497a5819784d6e56786783fba52c7fad6053;hb=a4ed524753cd61bd2c52b9af041eabe83ea1d503;hp=9a6e23a44e0f07372f341af80fa65de0b683cfd5;hpb=4cc93d2296593047de7a0c84455855832596bde9;p=gnulib.git

diff --git a/lib/nproc.c b/lib/nproc.c
index 9a6e23a44..7ebf497a5 100644
--- a/lib/nproc.c
+++ b/lib/nproc.c
@@ -1,6 +1,6 @@
 /* Detect the number of processors.
 
-   Copyright (C) 2009 Free Software Foundation, Inc.
+   Copyright (C) 2009-2011 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
@@ -16,22 +16,342 @@
    along with this program; if not, write to the Free Software Foundation,
    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
 
-/* Written by Glen Lenker.  */
+/* Written by Glen Lenker and Bruno Haible.  */
 
 #include <config.h>
 #include "nproc.h"
 
+#include <stdlib.h>
 #include <unistd.h>
 
-/* Return the total number of processors.  The result is guaranteed to
-   be at least 1.  */
+#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/pstat.h>
+#endif
+
+#if HAVE_SYS_SYSMP_H
+# include <sys/sysmp.h>
+#endif
+
+#if HAVE_SYS_PARAM_H
+# include <sys/param.h>
+#endif
+
+#if HAVE_SYS_SYSCTL_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 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)
 {
-#ifdef _SC_NPROCESSORS_ONLN
-  long int nprocs = sysconf (_SC_NPROCESSORS_ONLN);
-  if (0 < nprocs)
-    return nprocs;
+  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 (nprocs > 0)
+          return nprocs;
+      }
+#endif
+    }
+  else /* query == NPROC_ALL */
+    {
+#if defined _SC_NPROCESSORS_CONF
+      { /* This works on glibc, MacOS 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 (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 && 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.  */
+    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.  */
+    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)
+      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;