posix/sched_cpucount.c

   1 /* Copyright (C) 2007-2017 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <sched.h>
  19
  20
  21 int
  22 __sched_cpucount (size_t setsize, const cpu_set_t *setp)
  23 {
  24   int s = 0;
  25   const __cpu_mask *p = setp->__bits;
  26   const __cpu_mask *end = &setp->__bits[setsize / sizeof (__cpu_mask)];
  27
  28   while (p < end)
  29     {
  30       __cpu_mask l = *p++;
  31
  32 #ifdef POPCNT
  33       s += POPCNT (l);
  34 #else
  35       if (l == 0)
  36         continue;
  37
  38       _Static_assert (sizeof (l) == sizeof (unsigned int)
  39                       || sizeof (l) == sizeof (unsigned long)
  40                       || sizeof (l) == sizeof (unsigned long long),
  41                       "sizeof (__cpu_mask");
  42       if (sizeof (__cpu_mask) == sizeof (unsigned int))
  43         s += __builtin_popcount (l);
  44       else if (sizeof (__cpu_mask) == sizeof (unsigned long))
  45         s += __builtin_popcountl (l);
  46       else
  47         s += __builtin_popcountll (l);
  48 #endif
  49     }
  50
  51   return s;
  52 }