#define rdtsc(low) \
   __asm__ __volatile__("rdtsc" : "=a" (low) : : "edx")

#define TIME(x,y) \
	min = 100000;						\
	for (i = 0; i < 1000; i++) {				\
		unsigned long start,end;			\
		rdtsc(start);					\
		x;						\
		rdtsc(end);					\
		end -= start;					\
		if (end < min)					\
			min = end;				\
	}							\
	printf(y ": %d cycles\n", min);

#define LOCK	asm volatile("lock ; addl $0,0(%esp)")
#define CPUID	asm volatile("cpuid": : :"ax", "dx", "cx", "bx")

int main()
{
	unsigned long min;
	int i;

	TIME(/* */, "nothing");
	TIME(LOCK, "locked add");
	TIME(CPUID, "cpuid");
}