runtime.GOMAXPROCS(1)
	// Disable GC so we have complete control of what we're testing.
	debug.SetGCPercent(-1)
	// Out of an abundance of caution, also make sure that there are
	// no GCs actively in progress. The sweep phase of a GC cycle
	// for instance tries to preempt Ps at the very beginning.
	runtime.GC()

	// Start a goroutine with no sync safe-points.
	var ready, ready2 uint32
	go func() {
		for {

	traceEvGCBegin            // GC start [timestamp, seq, stack ID]
	traceEvGCEnd              // GC done [timestamp, seq]
	traceEvGCSweepActive      // GC sweep active [timestamp, P ID]
	traceEvGCSweepBegin       // GC sweep start [timestamp, stack ID]
	traceEvGCSweepEnd         // GC sweep done [timestamp, swept bytes, reclaimed bytes]
	traceEvGCMarkAssistActive // GC mark assist active [timestamp, goroutine ID]

NONE
< sysmon
< scavenge, forcegc;

# Defer
NONE < defer;

# GC
NONE <
  sweepWaiters,
  assistQueue,
  sweep;

# Test only
NONE < testR, testW;

NONE < timerSend;

# Scheduler, timers, netpoll
NONE < allocmW, execW, cpuprof, pollCache, pollDesc, wakeableSleep;
scavenge, sweep, testR, wakeableSleep, timerSend < hchan;
assistQueue,
  cpuprof,
  forcegc,
  hchan,

	defer debug.SetGCPercent(debug.SetGCPercent(-1))
	// SetGCPercent waits until the mark phase is over, but the runtime
	// also preempts at the start of the sweep phase, so make sure that's
	// done too. See #49695.
	runtime.GC()

	// Temporarily rewind the stack and trigger SIGSETXID
	issue9400.RewindAndSetgid()

	// Check test pattern
	for i := range big {

	// access (since that may free the backing store).
	allspans []*mspan // all spans out there

	// Proportional sweep
	//
	// These parameters represent a linear function from gcController.heapLive
	// to page sweep count. The proportional sweep system works to
	// stay in the black by keeping the current page sweep count
	// above this line at the current gcController.heapLive.
	//

	EvGCBegin            // GC start [timestamp, seq, stack ID]
	EvGCEnd              // GC done [timestamp, seq]
	EvGCSweepActive      // GC sweep active [timestamp, P ID]
	EvGCSweepBegin       // GC sweep start [timestamp, stack ID]
	EvGCSweepEnd         // GC sweep done [timestamp, swept bytes, reclaimed bytes]
	EvGCMarkAssistActive // GC mark assist active [timestamp, goroutine ID]

	// Disable GC for this test (see issue #10958).
	defer debug.SetGCPercent(debug.SetGCPercent(-1))
	// SetGCPercent waits until the mark phase is over, but the runtime
	// also preempts at the start of the sweep phase, so make sure that's
	// done too.
	GC()

	doTestParallelReaders(1)
	doTestParallelReaders(3)
	doTestParallelReaders(4)
}

func reader(rwm *RWMutex, num_iterations int, activity *int32, cdone chan bool) {

	}
	runtime.ReadMemStats(&m.curMark.endM)
	if m.gc == GC {
		runtime.GC()
		runtime.ReadMemStats(&m.curMark.gcM)
		if m.shouldPProf() {
			// Collect a profile of the live heap. Do a
			// second GC to force sweep completion so we
			// get a complete snapshot of the live heap at
			// the end of this phase.
			runtime.GC()
			f, err := os.Create(makePProfFilename(m.filebase, m.curMark.name, "memprof"))
			if err != nil {

		if sweepDistTrigger > goal {
			// Set the goal to maintain a minimum sweep distance since
			// the last call to commit. Note that we never want to do this
			// if we're in the memory limit regime, because it could push
			// the goal up.
			goal = sweepDistTrigger
		}
		// Since we ignore the sweep distance trigger in the memory
		// limit regime, we need to ensure we don't propagate it to

				cack <- true
				return
			default:
				runtime.Gosched()
			}
		}
	}()
	time.Sleep(10 * time.Millisecond)
	c <- true
	<-cack
}

func TestYieldLocked(t *testing.T) {
	const N = 10
	c := make(chan bool)
	go func() {
		runtime.LockOSThread()
		for i := 0; i < N; i++ {
			runtime.Gosched()
			time.Sleep(time.Millisecond)
		}
		c <- true
		// runtime.UnlockOSThread() is deliberately omitted
	}()