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

static int clock_gettime_syscall(clockid_t clk_id, struct timespec *tp)
{
	return syscall(__NR_clock_gettime, clk_id, tp);
}


int main(void)
{
	int i;
	struct timespec t, start;

	clock_gettime(CLOCK_REALTIME, &start);
	i = 0;
	do {
		clock_gettime(CLOCK_REALTIME, &t);
		i++;
	} while (t.tv_sec == start.tv_sec || t.tv_nsec < start.tv_nsec);
	printf("vdso hires:	%fns\n", 1000000000.0 / i);
	clock_gettime(CLOCK_REALTIME_COARSE, &start);
	i = 0;
	do {
		clock_gettime(CLOCK_REALTIME_COARSE, &t);
		i++;
	} while (t.tv_sec == start.tv_sec || t.tv_nsec < start.tv_nsec);
	printf("vdso coarse:	%fns\n", 1000000000.0 / i);

	clock_gettime_syscall(CLOCK_REALTIME, &start);
	i = 0;
	do {
		clock_gettime_syscall(CLOCK_REALTIME, &t);
		i++;
	} while (t.tv_sec == start.tv_sec || t.tv_nsec < start.tv_nsec);

	printf("sysc hires:	%fns\n", 1000000000.0 / i);
	clock_gettime_syscall(CLOCK_REALTIME_COARSE, &start);
	i = 0;
	do {
		clock_gettime_syscall(CLOCK_REALTIME_COARSE, &t);
		i++;
	} while (t.tv_sec == start.tv_sec || t.tv_nsec < start.tv_nsec);
	printf("sysc coarse:	%fns\n", 1000000000.0 / i);

	return 0;
}