semaMutexProfile
)

// Called from runtime.
func semacquire(addr *uint32) {
	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
	}

		return errorString("tracing is already enabled")
	}
	// Block until cleanup of the last trace is done.
	semacquire(&traceShutdownSema)
	semrelease(&traceShutdownSema)

	// Hold traceAdvanceSema across trace start, since we'll want it on
	// the other side of tracing being enabled globally.
	semacquire(&traceAdvanceSema)

	// Initialize CPU profile -> trace ingestion.
	traceInitReadCPU()

	waitReasonFinalizerWait                           // "finalizer wait"
	waitReasonForceGCIdle                             // "force gc (idle)"
	waitReasonSemacquire                              // "semacquire"
	waitReasonSleep                                   // "sleep"
	waitReasonSyncCondWait                            // "sync.Cond.Wait"
	waitReasonSyncMutexLock                           // "sync.Mutex.Lock"

				"runtime.semrelease1",
				"runtime_test.TestRuntimeLockMetricsAndProfile.func6.1",
				"runtime_test.(*contentionWorker).run",
			},
			{
				"runtime.unlock",
				"runtime.semacquire1",
				"runtime.semacquire",
				"runtime_test.TestRuntimeLockMetricsAndProfile.func6.1",
				"runtime_test.(*contentionWorker).run",
			},
		}

var Lock = lock
var Unlock = unlock

var MutexContended = mutexContended

func SemRootLock(addr *uint32) *mutex {
	root := semtable.rootFor(addr)
	return &root.lock
}

var Semacquire = semacquire
var Semrelease1 = semrelease1

func SemNwait(addr *uint32) uint32 {
	root := semtable.rootFor(addr)
	return root.nwait.Load()
}

const SemTableSize = semTabSize

// true in the following cases:
// - The goroutine lost its P, it ran some other code, and then got it back. It's now running with that P.
// - The goroutine lost its P and was unable to reacquire it, and is now running without a P.
// - The goroutine lost its P and acquired a different one, and is now running with that P.
func (tl traceLocker) GoSysExit(lostP bool) {
	ev := traceEvGoSyscallEnd