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d7f74150e5
* Small refactor of my_getncpus function to compile for very old glibc < 2.6. * Cleanup code to eliminate duplication.
81 lines
2.4 KiB
C
81 lines
2.4 KiB
C
/*
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Copyright (c) 2006, 2010, Oracle and/or its affiliates
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
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/* get the number of (online) CPUs */
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#include "mysys_priv.h"
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#if defined(__FreeBSD__) && defined(HAVE_PTHREAD_GETAFFINITY_NP)
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#include <pthread_np.h>
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#include <sys/cpuset.h>
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#endif
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static int ncpus=0;
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int my_getncpus(void)
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{
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if (!ncpus)
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{
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/*
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First attempt to get the total number of available cores. sysconf is
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the fallback, but it can return a larger number. It will return the
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total number of cores, not the ones available to the process - as
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configured via core affinity.
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*/
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#if (defined(__linux__) || defined(__FreeBSD__)) && defined(HAVE_PTHREAD_GETAFFINITY_NP)
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cpu_set_t set;
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if (pthread_getaffinity_np(pthread_self(), sizeof(set), &set) == 0)
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{
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#ifdef CPU_COUNT
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/* CPU_COUNT was introduced with glibc 2.6. */
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ncpus= CPU_COUNT(&set);
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#else
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/* Implementation for platforms with glibc < 2.6 */
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size_t i;
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for (i= 0; i < CPU_SETSIZE; i++)
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if (CPU_ISSET(i, &set))
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ncpus++;
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#endif
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return ncpus;
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}
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#endif /* (__linux__ || __FreeBSD__) && HAVE_PTHREAD_GETAFFINITY_NP */
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#ifdef _SC_NPROCESSORS_ONLN
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ncpus= sysconf(_SC_NPROCESSORS_ONLN);
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#elif defined(__WIN__)
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SYSTEM_INFO sysinfo;
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/*
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We are not calling GetNativeSystemInfo here because (1) we
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don't believe that they return different values for number
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of processors and (2) if WOW64 limits processors for Win32
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then we don't want to try to override that.
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*/
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GetSystemInfo(&sysinfo);
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ncpus= sysinfo.dwNumberOfProcessors;
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#else
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/* Unknown so play safe: assume SMP and forbid uniprocessor build */
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ncpus= 2;
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#endif
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}
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return ncpus;
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}
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