#define _GNU_SOURCE
#include <utmpx.h>
#include <sys/time.h>
#include <unistd.h>

/* Usage: ./schedtest <cpu core to test> */

int miliseconds() {
  struct timeval tv;
  gettimeofday(&tv, 0);
  return tv.tv_usec/1000;
}

int main(int argc, char *argv[]) {
  int lives = 1000, time, lasttime, childs, cores, core_to_test;
  cores = sysconf(_SC_NPROCESSORS_ONLN);
  childs = cores * 2;
  if (argc > 1)
    core_to_test = atoi(argv[1]);
  else
    core_to_test = cores-1;
  while (childs-- && !fork());
  while (lives) {
    time = miliseconds();
    if (lasttime != time && sched_getcpu() != core_to_test)
       lives--;
    lasttime = time;
  }
  return 0;
}