summaryrefslogtreecommitdiff
path: root/nacl/cpucycles/monotonic.c
blob: 412a44fbd8836f8fcaabcb2ae112a55614020874 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
#include <time.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/sysctl.h>

static double cpufrequency = 0;

static void init(void)
{
  long result = 0; size_t resultlen = sizeof(long);
  sysctlbyname("machdep.tsc_freq",&result,&resultlen,0,0);
  cpufrequency = result;
}

long long cpucycles_monotonic(void)
{
  double result;
  struct timespec t;
  if (!cpufrequency) init();
  clock_gettime(CLOCK_MONOTONIC,&t);
  result = t.tv_nsec;
  result *= 0.000000001;
  result += (double) t.tv_sec;
  result *= cpufrequency;
  return result;
}

long long cpucycles_monotonic_persecond(void)
{
  if (!cpufrequency) init();
  return cpufrequency;
}