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/*
Copyright (c) 2006, 2010, Oracle and/or its affiliates
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
the Free Software Foundation; version 2 of the License.
This program 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 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 St, Fifth Floor, Boston, MA 02110-1335 USA */
/* get the number of (online) CPUs */
#include "mysys_priv.h"
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#if defined(__FreeBSD__) && defined(HAVE_PTHREAD_GETAFFINITY_NP)
#include <pthread_np.h>
#include <sys/cpuset.h>
#endif
static int ncpus=0;
int my_getncpus(void)
{
if (!ncpus)
{
/*
First attempt to get the total number of available cores. sysconf is
the fallback, but it can return a larger number. It will return the
total number of cores, not the ones available to the process - as
configured via core affinity.
*/
#if (defined(__linux__) || defined(__FreeBSD__)) && defined(HAVE_PTHREAD_GETAFFINITY_NP)
#ifdef __linux__
cpu_set_t set;
#else
cpuset_t set;
#endif
if (pthread_getaffinity_np(pthread_self(), sizeof(set), &set) == 0)
{
#ifdef CPU_COUNT
/* CPU_COUNT was introduced with glibc 2.6. */
ncpus= CPU_COUNT(&set);
#else
/* Implementation for platforms with glibc < 2.6 */
size_t i;
for (i= 0; i < CPU_SETSIZE; i++)
if (CPU_ISSET(i, &set))
ncpus++;
#endif
return ncpus;
}
#endif /* (__linux__ || __FreeBSD__) && HAVE_PTHREAD_GETAFFINITY_NP */
#ifdef _SC_NPROCESSORS_ONLN
ncpus= sysconf(_SC_NPROCESSORS_ONLN);
#elif defined(_WIN32)
SYSTEM_INFO sysinfo;
/*
We are not calling GetNativeSystemInfo here because (1) we
don't believe that they return different values for number
of processors and (2) if WOW64 limits processors for Win32
then we don't want to try to override that.
*/
GetSystemInfo(&sysinfo);
ncpus= sysinfo.dwNumberOfProcessors;
#else
/* Unknown so play safe: assume SMP and forbid uniprocessor build */
ncpus= 2;
#endif
}
return ncpus;
}
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