Function rdtsc

freebsd/net/altq/altq_subr.c:968–974

#if defined(__OpenBSD__) && defined(__i386__)
static __inline u_int64_t
rdtsc(void)
{
	u_int64_t rv;
	__asm __volatile(".byte 0x0f, 0x31" : "=A" (rv));
	return (rv);
}
#endif /* __OpenBSD__ && __i386__ */

u_int64_t