release/src/router/dnscrypt/src/libnacl/cpucycles/monotonic.c

   1 #include <time.h>
   2 #include <stdio.h>
   3 #include <unistd.h>
   4 #include <sys/time.h>
   5 #include <sys/types.h>
   6 #include <sys/param.h>
   7 #include <sys/sysctl.h>
   8
   9 static double cpufrequency = 0;
  10
  11 static void init(void)
  12 {
  13   long result = 0; size_t resultlen = sizeof(long);
  14   sysctlbyname("machdep.tsc_freq",&result,&resultlen,0,0);
  15   cpufrequency = result;
  16 }
  17
  18 long long cpucycles_monotonic(void)
  19 {
  20   double result;
  21   struct timespec t;
  22   if (!cpufrequency) init();
  23   clock_gettime(CLOCK_MONOTONIC,&t);
  24   result = t.tv_nsec;
  25   result *= 0.000000001;
  26   result += (double) t.tv_sec;
  27   result *= cpufrequency;
  28   return result;
  29 }
  30
  31 long long cpucycles_monotonic_persecond(void)
  32 {
  33   if (!cpufrequency) init();
  34   return cpufrequency;
  35 }