dt0 := t0 - acquiretime
			dt := dt0
			if s.waiters != 0 {
				dtail := t0 - tailtime
				dt += (dtail + dt0) / 2 * int64(s.waiters)
			}
			mutexevent(dt, 3+skipframes)
		}
		if s.ticket != 0 {
			throw("corrupted semaphore ticket")
		}
		if handoff && cansemacquire(addr) {
			s.ticket = 1
		}
		readyWithTime(s, 5+skipframes)

	if rate < 0 {
		return int(mutexprofilerate)
	}
	old := mutexprofilerate
	atomic.Store64(&mutexprofilerate, uint64(rate))
	return int(old)
}

//go:linkname mutexevent sync.event
func mutexevent(cycles int64, skip int) {
	if cycles < 0 {
		cycles = 0
	}
	rate := int64(atomic.Load64(&mutexprofilerate))
	if rate > 0 && cheaprand64()%rate == 0 {