gettimeofday() benchmark.

gistfile1.c

#include <stdint.h>
#include <stdio.h>
#include <time.h>
#include <sys/time.h>
#include <assert.h>

#define ITERS 1000000000

static uint64_t gettime(void) {
  struct timespec ts;

  if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0) {
    assert(0);
  }

  return ((uint64_t)ts.tv_sec) * 1000 * 1000 * 1000 + ts.tv_nsec;
}

int main(int argc, char *argv[]) {
  struct timeval tv;
  uint64_t start_time;
  uint64_t end_time;
  int i;

  (void)argc;
  (void)argv;

  start_time = gettime();
  for (i = 0; i < ITERS; ++i) {
    gettimeofday(&tv, NULL);
  }
  end_time = gettime();

  fprintf(stdout, "gettimeofday() = %llu ns\n", (end_time - start_time) / ITERS);

  return 0;
}

Thanks!

$ ./a.out 
gettimeofday() = 21 ns

$ cat /etc/issue
Ubuntu 14.04.5 LTS

$ cat /proc/cpuinfo | grep model
model name	: Intel(R) Core(TM) i5-4258U CPU @ 2.40GHz