tests/benchmark/test_cycles_per_loop.c

   1 /*
   2  * test_cycles_per_loop.c
   3  *
   4  * Userspace RCU library - test cycles per loop
   5  *
   6  * Copyright February 2009 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22
  23 #include <urcu/arch.h>
  24 #include <stdio.h>
  25
  26 #define NR_LOOPS 1000000UL
  27
  28 static inline void loop_sleep(unsigned long loops)
  29 {
  30         while (loops-- != 0)
  31                 caa_cpu_relax();
  32 }
  33
  34 int main()
  35 {
  36         cycles_t time1, time2;
  37
  38         time1 = caa_get_cycles();
  39         loop_sleep(NR_LOOPS);
  40         time2 = caa_get_cycles();
  41         printf("CPU clock cycles per loop: %g\n", (time2 - time1) /
  42                                                   (double)NR_LOOPS);
  43         return 0;
  44 }