timetime.c

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

double getsec() {
  struct timespec tv;
  clock_gettime(CLOCK_MONOTONIC, &tv);

  return tv.tv_sec + tv.tv_nsec/1e9;
}

int main()
{
  int n = 100000;

  double t0, t1;
  struct timespec tv;


  t0 = getsec();
  for (int i=0; i<n; i++) {
    clock_gettime(CLOCK_MONOTONIC,&tv);
  }
  t1 = getsec();

  printf("%f [usec]\n", ((t1-t0)/n)*1e6);

  t0 = getsec();
  for (int i=0; i<n; i++) {
    struct timeval tv;
    gettimeofday(&tv, NULL);
  }
  t1 = getsec();

  printf("%f [usec]\n", ((t1-t0)/n)*1e6);

  t0 = getsec();
  for (int i=0; i<n; i++) {
    clock_gettime(CLOCK_MONOTONIC_COARSE,&tv);
  }
  t1 = getsec();

  printf("%f [usec]\n", ((t1-t0)/n)*1e6);

  t0 = getsec();
  for (int i=0; i<n; i++) {
    asm volatile ("rdtsc" ::: "rax", "rdx" );
  }
  t1 = getsec();

  printf("%f [usec]\n", ((t1-t0)/n)*1e6);

  t0 = getsec();
  for (int i=0; i<n; i++) {
    asm volatile ("rdtscp" ::: "rax", "rcx", "rdx");
  }
  t1 = getsec();

  printf("%f [usec]\n", ((t1-t0)/n)*1e6);

}