src/common/tuklib_cpucores.c

   1 ///////////////////////////////////////////////////////////////////////////////
   2 //
   3 /// \file       tuklib_cpucores.c
   4 /// \brief      Get the number of CPU cores online
   5 //
   6 //  Author:     Lasse Collin
   7 //
   8 //  This file has been put into the public domain.
   9 //  You can do whatever you want with this file.
  10 //
  11 ///////////////////////////////////////////////////////////////////////////////
  12
  13 #include "tuklib_cpucores.h"
  14
  15 #if defined(_WIN32) || defined(__CYGWIN__)
  16 #       ifndef _WIN32_WINNT
  17 #               define _WIN32_WINNT 0x0500
  18 #       endif
  19 #       include <windows.h>
  20
  21 // glibc >= 2.9
  22 #elif defined(TUKLIB_CPUCORES_SCHED_GETAFFINITY)
  23 #       include <sched.h>
  24
  25 // FreeBSD
  26 #elif defined(TUKLIB_CPUCORES_CPUSET)
  27 #       include <sys/param.h>
  28 #       include <sys/cpuset.h>
  29
  30 #elif defined(TUKLIB_CPUCORES_SYSCTL)
  31 #       ifdef HAVE_SYS_PARAM_H
  32 #               include <sys/param.h>
  33 #       endif
  34 #       include <sys/sysctl.h>
  35
  36 #elif defined(TUKLIB_CPUCORES_SYSCONF)
  37 #       include <unistd.h>
  38
  39 // HP-UX
  40 #elif defined(TUKLIB_CPUCORES_PSTAT_GETDYNAMIC)
  41 #       include <sys/param.h>
  42 #       include <sys/pstat.h>
  43 #endif
  44
  45
  46 extern uint32_t
  47 tuklib_cpucores(void)
  48 {
  49         uint32_t ret = 0;
  50
  51 #if defined(_WIN32) || defined(__CYGWIN__)
  52         SYSTEM_INFO sysinfo;
  53         GetSystemInfo(&sysinfo);
  54         ret = sysinfo.dwNumberOfProcessors;
  55
  56 #elif defined(TUKLIB_CPUCORES_SCHED_GETAFFINITY)
  57         cpu_set_t cpu_mask;
  58         if (sched_getaffinity(0, sizeof(cpu_mask), &cpu_mask) == 0)
  59                 ret = (uint32_t)CPU_COUNT(&cpu_mask);
  60
  61 #elif defined(TUKLIB_CPUCORES_CPUSET)
  62         cpuset_t set;
  63         if (cpuset_getaffinity(CPU_LEVEL_WHICH, CPU_WHICH_PID, -1,
  64                         sizeof(set), &set) == 0) {
  65 #       ifdef CPU_COUNT
  66                 ret = (uint32_t)CPU_COUNT(&set);
  67 #       else
  68                 for (unsigned i = 0; i < CPU_SETSIZE; ++i)
  69                         if (CPU_ISSET(i, &set))
  70                                 ++ret;
  71 #       endif
  72         }
  73
  74 #elif defined(TUKLIB_CPUCORES_SYSCTL)
  75         // On OpenBSD HW_NCPUONLINE tells the number of processor cores that
  76         // are online so it is preferred over HW_NCPU which also counts cores
  77         // that aren't currently available. The number of cores online is
  78         // often less than HW_NCPU because OpenBSD disables simultaneous
  79         // multi-threading (SMT) by default.
  80 #       ifdef HW_NCPUONLINE
  81         int name[2] = { CTL_HW, HW_NCPUONLINE };
  82 #       else
  83         int name[2] = { CTL_HW, HW_NCPU };
  84 #       endif
  85         int cpus;
  86         size_t cpus_size = sizeof(cpus);
  87         if (sysctl(name, 2, &cpus, &cpus_size, NULL, 0) != -1
  88                         && cpus_size == sizeof(cpus) && cpus > 0)
  89                 ret = (uint32_t)cpus;
  90
  91 #elif defined(TUKLIB_CPUCORES_SYSCONF)
  92 #       ifdef _SC_NPROCESSORS_ONLN
  93         // Most systems
  94         const long cpus = sysconf(_SC_NPROCESSORS_ONLN);
  95 #       else
  96         // IRIX
  97         const long cpus = sysconf(_SC_NPROC_ONLN);
  98 #       endif
  99         if (cpus > 0)
 100                 ret = (uint32_t)cpus;
 101
 102 #elif defined(TUKLIB_CPUCORES_PSTAT_GETDYNAMIC)
 103         struct pst_dynamic pst;
 104         if (pstat_getdynamic(&pst, sizeof(pst), 1, 0) != -1)
 105                 ret = (uint32_t)pst.psd_proc_cnt;
 106 #endif
 107
 108         return ret;
 109 }