semacquire1(addr, false, 0, 0, waitReasonSemacquire)
}

func semacquire1(addr *uint32, lifo bool, profile semaProfileFlags, skipframes int, reason waitReason) {
	gp := getg()
	if gp != gp.m.curg {
		throw("semacquire not on the G stack")
	}

	// Easy case.
	if cansemacquire(addr) {
		return
	}

	// Harder case:
	//	increment waiter count

	sigmask       sigset            // storage for saved signal mask
	tls           [tlsSlots]uintptr // thread-local storage (for x86 extern register)
	mstartfn      func()
	curg          *g       // current running goroutine
	caughtsig     guintptr // goroutine running during fatal signal
	p             puintptr // attached p for executing go code (nil if not executing go code)
	nextp         puintptr

}

// GoStart emits a GoStart event.
//
// Must be called with a valid P.
func (tl traceLocker) GoStart() {
	gp := getg().m.curg
	pp := gp.m.p
	w := tl.eventWriter(traceGoRunnable, traceProcRunning)
	w = w.write(traceEvGoStart, traceArg(gp.goid), gp.trace.nextSeq(tl.gen))
	if pp.ptr().gcMarkWorkerMode != gcMarkWorkerNotWorker {

	if gp := mp.g0; gp != nil && gp.stack.lo < sp && sp < gp.stack.hi {
		return gp
	}
	if gp := mp.gsignal; gp != nil && gp.stack.lo < sp && sp < gp.stack.hi {
		return gp
	}
	if gp := mp.curg; gp != nil && gp.stack.lo < sp && sp < gp.stack.hi {
		return gp
	}
	return nil
}

func profileLoop() {
	stdcall2(_SetThreadPriority, currentThread, _THREAD_PRIORITY_HIGHEST)

	for {

	// allocate and skew the stats.
	metricsLock()
	initMetrics()

	systemstack(func() {
		// Donate the racectx to g0. readMetricsLocked calls into the race detector
		// via map access.
		getg().racectx = getg().m.curg.racectx

		// Read the metrics once before in case it allocates and skews the metrics.
		// readMetricsLocked is designed to only allocate the first time it is called