--- /dev/null
+/* Detect the number of processors.
+
+ Copyright (C) 2009-2021 Free Software Foundation, Inc.
+
+ This file 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.
+
+ This file 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 this program. If not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Glen Lenker and Bruno Haible. */
+
+#include <config.h>
+#include "nproc.h"
+
+#include <limits.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/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 && ! defined __GLIBC__
+# include <sys/sysctl.h>
+#endif
+
+#if defined _WIN32 && ! defined __CYGWIN__
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+#endif
+
+#include "c-ctype.h"
+
+#include "minmax.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 __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;
+}
+
+
+/* Return the total number of processors. Here QUERY must be one of
+ NPROC_ALL, NPROC_CURRENT. The result is guaranteed to be at least 1. */
+static unsigned long int
+num_processors_ignoring_omp (enum nproc_query query)
+{
+ /* 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 or 2 (<https://sourceware.org/bugzilla/show_bug.cgi?id=21542>),
+ 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, 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 or 2. But we wish to guarantee that
+ num_processors (NPROC_ALL) >= num_processors (NPROC_CURRENT). */
+ if (nprocs == 1 || nprocs == 2)
+ {
+ unsigned long nprocs_current = num_processors_via_affinity_mask ();
+
+ if (/* nprocs_current > 0 && */ nprocs_current > nprocs)
+ 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 && getuid () != 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 __GLIBC__ && defined HW_NCPU
+ { /* This works on Mac OS X, FreeBSD, NetBSD, OpenBSD. */
+ int nprocs;
+ size_t len = sizeof (nprocs);
+ static int const mib[][2] = {
+# ifdef HW_NCPUONLINE
+ { CTL_HW, HW_NCPUONLINE },
+# endif
+ { CTL_HW, HW_NCPU }
+ };
+ for (int i = 0; i < ARRAY_SIZE (mib); i++)
+ {
+ if (sysctl (mib[i], ARRAY_SIZE (mib[i]), &nprocs, &len, NULL, 0) == 0
+ && len == sizeof (nprocs)
+ && 0 < nprocs)
+ return nprocs;
+ }
+ }
+#endif
+
+#if 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;
+}
+
+/* Parse OMP environment variables without dependence on OMP.
+ Return 0 for invalid values. */
+static unsigned long int
+parse_omp_threads (char const* threads)
+{
+ unsigned long int ret = 0;
+
+ if (threads == NULL)
+ return ret;
+
+ /* The OpenMP spec says that the value assigned to the environment variables
+ "may have leading and trailing white space". */
+ while (*threads != '\0' && c_isspace (*threads))
+ threads++;
+
+ /* Convert it from positive decimal to 'unsigned long'. */
+ if (c_isdigit (*threads))
+ {
+ char *endptr = NULL;
+ unsigned long int value = strtoul (threads, &endptr, 10);
+
+ if (endptr != NULL)
+ {
+ while (*endptr != '\0' && c_isspace (*endptr))
+ endptr++;
+ if (*endptr == '\0')
+ return value;
+ /* Also accept the first value in a nesting level,
+ since we can't determine the nesting level from env vars. */
+ else if (*endptr == ',')
+ return value;
+ }
+ }
+
+ return ret;
+}
+
+unsigned long int
+num_processors (enum nproc_query query)
+{
+ unsigned long int omp_env_limit = ULONG_MAX;
+
+ if (query == NPROC_CURRENT_OVERRIDABLE)
+ {
+ unsigned long int omp_env_threads;
+ /* Honor the OpenMP environment variables, recognized also by all
+ programs that are based on OpenMP. */
+ omp_env_threads = parse_omp_threads (getenv ("OMP_NUM_THREADS"));
+ omp_env_limit = parse_omp_threads (getenv ("OMP_THREAD_LIMIT"));
+ if (! omp_env_limit)
+ omp_env_limit = ULONG_MAX;
+
+ if (omp_env_threads)
+ return MIN (omp_env_threads, omp_env_limit);
+
+ query = NPROC_CURRENT;
+ }
+ /* Here query is one of NPROC_ALL, NPROC_CURRENT. */
+ {
+ unsigned long nprocs = num_processors_ignoring_omp (query);
+ return MIN (nprocs, omp_env_limit);
+ }
+}
--- /dev/null
+# nproc.m4 serial 5
+dnl Copyright (C) 2009-2021 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_NPROC],
+[
+ gl_PREREQ_NPROC
+])
+
+# Prerequisites of lib/nproc.c.
+AC_DEFUN([gl_PREREQ_NPROC],
+[
+ dnl Persuade glibc <sched.h> to declare CPU_SETSIZE, CPU_ISSET etc.
+ AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+ AC_CHECK_HEADERS([sys/pstat.h sys/sysmp.h sys/param.h],,,
+ [AC_INCLUDES_DEFAULT])
+ dnl <sys/sysctl.h> requires <sys/param.h> on OpenBSD 4.0.
+ AC_CHECK_HEADERS([sys/sysctl.h],,,
+ [AC_INCLUDES_DEFAULT
+ #if HAVE_SYS_PARAM_H
+ # include <sys/param.h>
+ #endif
+ ])
+
+ AC_CHECK_FUNCS([sched_getaffinity sched_getaffinity_np \
+ pstat_getdynamic sysmp sysctl])
+
+ dnl Test whether sched_getaffinity has the expected declaration.
+ dnl glibc 2.3.[0-2]:
+ dnl int sched_getaffinity (pid_t, unsigned int, unsigned long int *);
+ dnl glibc 2.3.3:
+ dnl int sched_getaffinity (pid_t, cpu_set_t *);
+ dnl glibc >= 2.3.4:
+ dnl int sched_getaffinity (pid_t, size_t, cpu_set_t *);
+ if test $ac_cv_func_sched_getaffinity = yes; then
+ AC_CACHE_CHECK([for glibc compatible sched_getaffinity],
+ [gl_cv_func_sched_getaffinity3],
+ [AC_COMPILE_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <errno.h>
+ #include <sched.h>]],
+ [[sched_getaffinity (0, 0, (cpu_set_t *) 0);]])],
+ [gl_cv_func_sched_getaffinity3=yes],
+ [gl_cv_func_sched_getaffinity3=no])
+ ])
+ if test $gl_cv_func_sched_getaffinity3 = yes; then
+ AC_DEFINE([HAVE_SCHED_GETAFFINITY_LIKE_GLIBC], [1],
+ [Define to 1 if sched_getaffinity has a glibc compatible declaration.])
+ fi
+ fi
+])
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