if extHeapGoal > hardGoal {
			extHeapGoal = hardGoal
		}
		heapGoal = extHeapGoal
	}
	if int64(live) > heapGoal {
		// We're already past our heap goal, even the extrapolated one.
		// Leave ourselves some extra runway, so in the worst case we
		// finish by that point.
		const maxOvershoot = 1.1
		heapGoal = int64(float64(heapGoal) * maxOvershoot)

	return float64(r.heapGoal - r.heapTrigger)
}

func (r *gcCycleResult) triggerRatio() float64 {
	return float64(r.heapTrigger-r.heapLive) / float64(r.heapGoal-r.heapLive)
}

func (r *gcCycleResult) String() string {
	return fmt.Sprintf("%d %2.1f%% %d->%d->%d (goal: %d)", r.cycle, r.gcUtilization*100, r.heapLive, r.heapTrigger, r.heapPeak, r.heapGoal)
}

func assertInEpsilon(t *testing.T, name string, a, b, epsilon float64) {

}

// HeapGoal reads the current heap goal and emits a HeapGoal event.
func (tl traceLocker) HeapGoal() {
	heapGoal := gcController.heapGoal()
	if heapGoal == ^uint64(0) {
		// Heap-based triggering is disabled.
		heapGoal = 0
	}
	tl.eventWriter(traceGoRunning, traceProcRunning).commit(traceEvHeapGoal, traceArg(heapGoal))
}

	EvHeapAlloc         = 33 // gcController.heapLive change [timestamp, heap live bytes]
	EvHeapGoal          = 34 // gcController.heapGoal change [timestamp, heap goal bytes]
	EvTimerGoroutine    = 35 // denotes timer goroutine [timer goroutine id]
	EvFutileWakeup      = 36 // denotes that the previous wakeup of this goroutine was futile [timestamp]

	a.buckHashSys = memstats.buckhash_sys.load()
	a.gcMiscSys = memstats.gcMiscSys.load()
	a.otherSys = memstats.other_sys.load()
	a.heapGoal = gcController.heapGoal()
	a.gcCyclesDone = uint64(memstats.numgc)
	a.gcCyclesForced = uint64(memstats.numforcedgc)

	systemstack(func() {
		lock(&mheap_.lock)
		a.mSpanSys = memstats.mspan_sys.load()
		a.mSpanInUse = uint64(mheap_.spanalloc.inuse)
		a.mCacheSys = memstats.mcache_sys.load()

	EvGCMarkAssistEnd    // GC mark assist done [timestamp]
	EvHeapAlloc          // gcController.heapLive change [timestamp, heap alloc in bytes]
	EvHeapGoal           // gcController.heapGoal() change [timestamp, heap goal in bytes]

	// Annotations.
	EvGoLabel         // apply string label to current running goroutine [timestamp, label string ID]

// For the former, the goal is defined as:
//   (retainExtraPercent+100) / 100 * (heapGoal / lastHeapGoal) * lastHeapInUse
//
// Essentially, we wish to have the application's RSS track the heap goal, but
// the heap goal is defined in terms of bytes of objects, rather than pages like
// RSS. As a result, we need to take into account for fragmentation internal to
// spans. heapGoal / lastHeapGoal defines the ratio between the current heap goal

	traceEvGCMarkAssistEnd    // GC mark assist done [timestamp]
	traceEvHeapAlloc          // gcController.heapLive change [timestamp, heap alloc in bytes]
	traceEvHeapGoal           // gcController.heapGoal() change [timestamp, heap goal in bytes]

	// Annotations.
	traceEvGoLabel         // apply string label to current running goroutine [timestamp, label string ID]

	m := ev.Metric()
	switch m.Name {
	case "/memory/classes/heap/objects:bytes":
		ctx.HeapAlloc(ctx.elapsed(ev.Time()), m.Value.Uint64())
	case "/gc/heap/goal:bytes":
		ctx.HeapGoal(ctx.elapsed(ev.Time()), m.Value.Uint64())
	case "/sched/gomaxprocs:threads":
		ctx.Gomaxprocs(m.Value.Uint64())
	}
}

// procRangeGenerator implements a generic handler for EventRange* events whose Scope.Kind is

		memstats.buckhash_sys.load() + memstats.gcMiscSys.load() + memstats.other_sys.load() +
		stackInUse + gcWorkBufInUse + gcProgPtrScalarBitsInUse

	heapGoal := gcController.heapGoal()

	if doubleCheckReadMemStats {
		// Only check this if we're debugging. It would be bad to crash an application
		// just because the debugging stats are wrong. We mostly rely on tests to catch