/* Measure the number of clock ticks it takes to measure the number of
   clock ticks */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

unsigned long long rdtsc (void) {
  unsigned long long returned;
  asm volatile (" rdtsc " : "=A" (returned));
  return returned;
}

int main(void) {
  while (1) {
    int j;
    int minimum = (1 << 30);
    for (j = 0; j < 10; j++) {
      unsigned long long elapsed = -rdtsc();
      elapsed += rdtsc();
      minimum = (elapsed < minimum) ? elapsed : minimum;
    }
    printf("%i\n", minimum);
    usleep(100000); /* 10Hz */
  }
  return 0;
}