}

func Read(fd int, p []byte) (n int, err error) {
	n, err = read(fd, p)
	if raceenabled {
		if n > 0 {
			raceWriteRange(unsafe.Pointer(&p[0]), n)
		}
		if err == nil {
			raceAcquire(unsafe.Pointer(&ioSync))
		}
	}
	return
}

func Write(fd int, p []byte) (n int, err error) {
	if raceenabled {
		raceReleaseMerge(unsafe.Pointer(&ioSync))
	}
	n, err = write(fd, p)

	// but we need to make sure the tracer can only observe the
	// start and end states to maintain a coherent model and avoid
	// emitting an event for every single transition.
	trace := traceAcquire()

	if locked {
		// Detach the goroutine from the thread; we'll attach to the goroutine we're
		// switching to before returning.
		gp.lockedm.set(nil)
	}

	if exit {

		// internal/runtime/atomic.Loaduintptr is only intrinsified on these platforms.
		want["runtime"] = append(want["runtime"], "traceAcquire")
	}
	if bits.UintSize == 64 {
		// mix is only defined on 64-bit architectures
		want["runtime"] = append(want["runtime"], "mix")
		// (*Bool).CompareAndSwap is just over budget on 32-bit systems (386, arm).

		*inc = (*newInc)(g.name)
		if raceenabled {
			racereleasemerge(unsafe.Pointer(&g.inc))
		}
		if !g.inc.CompareAndSwap(nil, inc) {
			inc = g.inc.Load()
		}
	}
	if raceenabled {
		raceacquire(unsafe.Pointer(&g.inc))
	}
	(*inc)()
}

func godebugNotify(envChanged bool) {
	update := godebugUpdate.Load()
	var env string
	if p := godebugEnv.Load(); p != nil {
		env = *p
	}

retry:
	if gcCPULimiter.limiting() {
		// If the CPU limiter is enabled, intentionally don't
		// assist to reduce the amount of CPU time spent in the GC.
		if enteredMarkAssistForTracing {
			trace := traceAcquire()
			if trace.ok() {
				trace.GCMarkAssistDone()
				// Set this *after* we trace the end to make sure
				// that we emit an in-progress event if this is
				// the first event for the goroutine in the trace

var reflectOffs struct {
	lock mutex
	next int32
	m    map[int32]unsafe.Pointer
	minv map[unsafe.Pointer]int32
}

func reflectOffsLock() {
	lock(&reflectOffs.lock)
	if raceenabled {
		raceacquire(unsafe.Pointer(&reflectOffs.lock))
	}
}

func reflectOffsUnlock() {
	if raceenabled {
		racerelease(unsafe.Pointer(&reflectOffs.lock))
	}
	unlock(&reflectOffs.lock)
}

	goto retc

rclose:
	// read at end of closed channel
	selunlock(scases, lockorder)
	recvOK = false
	if cas.elem != nil {
		typedmemclr(c.elemtype, cas.elem)
	}
	if raceenabled {
		raceacquire(c.raceaddr())
	}
	goto retc

send:
	// can send to a sleeping receiver (sg)
	if raceenabled {
		raceReadObjectPC(c.elemtype, cas.elem, casePC(casi), chansendpc)
	}
	if msanenabled {

			return nil, now
		}
		// Run a fractional worker.
		pp.gcMarkWorkerMode = gcMarkWorkerFractionalMode
	}

	// Run the background mark worker.
	gp := node.gp.ptr()
	trace := traceAcquire()
	casgstatus(gp, _Gwaiting, _Grunnable)
	if trace.ok() {
		trace.GoUnpark(gp, 0)
		traceRelease(trace)
	}
	return gp, now
}

		// goroutine and uses atomics to write the updated queue indices,
		// and then the read-out from the signal handler buffer uses
		// atomics to read those queue indices.
		raceacquire(unsafe.Pointer(&labelSync))
	}

	return data[:di], tags[:ti], false

	// expensive enough that queueing up goroutines and handing off between
	// them will be noticeably better-behaved.
	semacquire1(&metricsSema, true, 0, 0, waitReasonSemacquire)
	if raceenabled {
		raceacquire(unsafe.Pointer(&metricsSema))
	}
}

func metricsUnlock() {
	if raceenabled {
		racerelease(unsafe.Pointer(&metricsSema))
	}
	semrelease(&metricsSema)
}