Use SeatSeconds

staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/queueset/queueset.go

@@ -76,9 +76,9 @@ type queueSetCompleter struct {
 // not end in "Locked" either acquires the lock or does not care about
 // locking.
 type queueSet struct {
-	clock                   eventclock.Interface
+	clock                    eventclock.Interface
-	estimatedServiceSeconds float64
+	estimatedServiceDuration time.Duration
-	obsPair                 metrics.TimedObserverPair
+	obsPair                  metrics.TimedObserverPair
 
 	promiseFactory promiseFactory
 
@@ -102,9 +102,9 @@ type queueSet struct {
 	// queues are still draining.
 	queues []*queue
 
-	// virtualTime is the amount of seat-seconds allocated per queue since process startup.
+	// currentR is the amount of seat-seconds allocated per queue since process startup.
 	// This is our generalization of the progress meter named R in the original fair queuing work.
-	virtualTime float64
+	currentR SeatSeconds
 
 	// lastRealTime is what `clock.Now()` yielded when `virtualTime` was last updated
 	lastRealTime time.Time
@@ -173,12 +173,12 @@ func (qsc *queueSetCompleter) Complete(dCfg fq.DispatchingConfig) fq.QueueSet {
 	qs := qsc.theSet
 	if qs == nil {
 		qs = &queueSet{
-			clock:                   qsc.factory.clock,
+			clock:                    qsc.factory.clock,
-			estimatedServiceSeconds: 0.003,
+			estimatedServiceDuration: 3 * time.Millisecond,
-			obsPair:                 qsc.obsPair,
+			obsPair:                  qsc.obsPair,
-			qCfg:                    qsc.qCfg,
+			qCfg:                     qsc.qCfg,
-			virtualTime:             0,
+			currentR:                 0,
-			lastRealTime:            qsc.factory.clock.Now(),
+			lastRealTime:             qsc.factory.clock.Now(),
 		}
 		qs.promiseFactory = qsc.factory.promiseFactoryFactory(qs)
 	}
@@ -407,10 +407,14 @@ func (qs *queueSet) lockAndSyncTime() {
 // lock and before modifying the state of any queue.
 func (qs *queueSet) syncTimeLocked() {
 	realNow := qs.clock.Now()
-	timeSinceLast := realNow.Sub(qs.lastRealTime).Seconds()
+	timeSinceLast := realNow.Sub(qs.lastRealTime)
 	qs.lastRealTime = realNow
-	qs.virtualTime += timeSinceLast * qs.getVirtualTimeRatioLocked()
+	prevR := qs.currentR
-	metrics.SetCurrentR(qs.qCfg.Name, qs.virtualTime)
+	qs.currentR += SeatsTimesDuration(qs.getVirtualTimeRatioLocked(), timeSinceLast)
+	if qs.currentR < prevR {
+		klog.ErrorS(errors.New("progress meter wrapped around"), "Wrap", "QS", qs.qCfg.Name, "prevR", prevR, "currentR", qs.currentR)
+	}
+	metrics.SetCurrentR(qs.qCfg.Name, qs.currentR.ToFloat())
 }
 
 // getVirtualTimeRatio calculates the rate at which virtual time has
@@ -460,7 +464,7 @@ func (qs *queueSet) timeoutOldRequestsAndRejectOrEnqueueLocked(ctx context.Conte
 		ctx:               ctx,
 		decision:          qs.promiseFactory(nil, ctx.Done(), decisionCancel),
 		arrivalTime:       qs.clock.Now(),
-		arrivalR:          qs.virtualTime,
+		arrivalR:          qs.currentR,
 		queue:             queue,
 		descr1:            descr1,
 		descr2:            descr2,
@@ -495,7 +499,7 @@ func (qs *queueSet) shuffleShardLocked(hashValue uint64, descr1, descr2 interfac
 		// Ideally, this should be based on projected completion time in the
 		// virtual world of the youngest request in the queue.
 		thisSeatsSum := waitingSeats + queue.seatsInUse
-		klog.V(7).Infof("QS(%s): For request %#+v %#+v considering queue %d of %d seats waiting and %d executing, virtualStart=%vss", qs.qCfg.Name, descr1, descr2, queueIdx, waitingSeats, queue.seatsInUse, queue.virtualStart)
+		klog.V(7).Infof("QS(%s): For request %#+v %#+v considering queue %d of %d seats waiting and %d executing, nextDispatchR=%v", qs.qCfg.Name, descr1, descr2, queueIdx, waitingSeats, queue.seatsInUse, queue.nextDispatchR)
 		if thisSeatsSum < bestQueueSeatsSum {
 			bestQueueIdx, bestQueueSeatsSum = queueIdx, thisSeatsSum
 		}
@@ -503,7 +507,7 @@ func (qs *queueSet) shuffleShardLocked(hashValue uint64, descr1, descr2 interfac
 	}
 	if klog.V(6).Enabled() {
 		chosenQueue := qs.queues[bestQueueIdx]
-		klog.V(6).Infof("QS(%s) at r=%s v=%.9fss: For request %#+v %#+v chose queue %d, had seatSum %d & %d requests executing & virtualStart=%vss", qs.qCfg.Name, qs.clock.Now().Format(nsTimeFmt), qs.virtualTime, descr1, descr2, bestQueueIdx, chosenQueue.requests.SeatsSum(), chosenQueue.requestsExecuting, chosenQueue.virtualStart)
+		klog.V(6).Infof("QS(%s) at t=%s R=%v: For request %#+v %#+v chose queue %d, had seatSum %d & %d requests executing & virtualStart=%v", qs.qCfg.Name, qs.clock.Now().Format(nsTimeFmt), qs.currentR, descr1, descr2, bestQueueIdx, chosenQueue.requests.SeatsSum(), chosenQueue.requestsExecuting, chosenQueue.nextDispatchR)
 	}
 	return bestQueueIdx
 }
@@ -571,9 +575,9 @@ func (qs *queueSet) enqueueLocked(request *request) {
 	now := qs.clock.Now()
 	if queue.requests.Length() == 0 && queue.requestsExecuting == 0 {
 		// the queue’s start R is set to the virtual time.
-		queue.virtualStart = qs.virtualTime
+		queue.nextDispatchR = qs.currentR
 		if klog.V(6).Enabled() {
-			klog.Infof("QS(%s) at r=%s v=%.9fss: initialized queue %d start R due to request %#+v %#+v", qs.qCfg.Name, now.Format(nsTimeFmt), queue.virtualStart, queue.index, request.descr1, request.descr2)
+			klog.Infof("QS(%s) at t=%s R=%v: initialized queue %d start R due to request %#+v %#+v", qs.qCfg.Name, now.Format(nsTimeFmt), queue.nextDispatchR, queue.index, request.descr1, request.descr2)
 		}
 	}
 	queue.Enqueue(request)
@@ -609,7 +613,7 @@ func (qs *queueSet) dispatchSansQueueLocked(ctx context.Context, workEstimate *f
 		startTime:         now,
 		decision:          qs.promiseFactory(decisionExecute, ctx.Done(), decisionCancel),
 		arrivalTime:       now,
-		arrivalR:          qs.virtualTime,
+		arrivalR:          qs.currentR,
 		descr1:            descr1,
 		descr2:            descr2,
 		workEstimate:      *workEstimate,
@@ -620,7 +624,7 @@ func (qs *queueSet) dispatchSansQueueLocked(ctx context.Context, workEstimate *f
 	metrics.AddRequestConcurrencyInUse(qs.qCfg.Name, fsName, req.Seats())
 	qs.obsPair.RequestsExecuting.Add(1)
 	if klog.V(5).Enabled() {
-		klog.Infof("QS(%s) at r=%s v=%.9fss: immediate dispatch of request %q %#+v %#+v, qs will have %d executing", qs.qCfg.Name, now.Format(nsTimeFmt), qs.virtualTime, fsName, descr1, descr2, qs.totRequestsExecuting)
+		klog.Infof("QS(%s) at t=%s R=%v: immediate dispatch of request %q %#+v %#+v, qs will have %d executing", qs.qCfg.Name, now.Format(nsTimeFmt), qs.currentR, fsName, descr1, descr2, qs.totRequestsExecuting)
 	}
 	return req
 }
@@ -656,12 +660,12 @@ func (qs *queueSet) dispatchLocked() bool {
 	qs.obsPair.RequestsWaiting.Add(-1)
 	qs.obsPair.RequestsExecuting.Add(1)
 	if klog.V(6).Enabled() {
-		klog.Infof("QS(%s) at r=%s v=%.9fss: dispatching request %#+v %#+v work %v from queue %d with start R %.9fss, queue will have %d waiting & %d requests occupying %d seats, set will have %d seats occupied",
+		klog.Infof("QS(%s) at t=%s R=%v: dispatching request %#+v %#+v work %v from queue %d with start R %v, queue will have %d waiting & %d requests occupying %d seats, set will have %d seats occupied",
-			qs.qCfg.Name, request.startTime.Format(nsTimeFmt), qs.virtualTime, request.descr1, request.descr2,
+			qs.qCfg.Name, request.startTime.Format(nsTimeFmt), qs.currentR, request.descr1, request.descr2,
-			request.workEstimate, queue.index, queue.virtualStart, queue.requests.Length(), queue.requestsExecuting, queue.seatsInUse, qs.totSeatsInUse)
+			request.workEstimate, queue.index, queue.nextDispatchR, queue.requests.Length(), queue.requestsExecuting, queue.seatsInUse, qs.totSeatsInUse)
 	}
 	// When a request is dequeued for service -> qs.virtualStart += G * width
-	queue.virtualStart += qs.estimatedServiceSeconds * float64(request.Seats())
+	queue.nextDispatchR += SeatsTimesDuration(float64(request.Seats()), qs.estimatedServiceDuration)
 	qs.boundNextDispatch(queue)
 	request.decision.Set(decisionExecute)
 	return ok
@@ -694,11 +698,11 @@ func (qs *queueSet) canAccommodateSeatsLocked(seats int) bool {
 // returns the first one of those for which the virtual finish time of
 // the oldest waiting request is minimal.
 func (qs *queueSet) findDispatchQueueLocked() *queue {
-	minVirtualFinish := math.Inf(1)
+	minVirtualFinish := MaxSeatSeconds
-	sMin := math.Inf(1)
+	sMin := MaxSeatSeconds
-	dsMin := math.Inf(1)
+	dsMin := MaxSeatSeconds
-	sMax := math.Inf(-1)
+	sMax := MinSeatSeconds
-	dsMax := math.Inf(-1)
+	dsMax := MinSeatSeconds
 	var minQueue *queue
 	var minIndex int
 	nq := len(qs.queues)
@@ -707,12 +711,12 @@ func (qs *queueSet) findDispatchQueueLocked() *queue {
 		queue := qs.queues[qs.robinIndex]
 		oldestWaiting, _ := queue.requests.Peek()
 		if oldestWaiting != nil {
-			sMin = math.Min(sMin, queue.virtualStart)
+			sMin = ssMin(sMin, queue.nextDispatchR)
-			sMax = math.Max(sMax, queue.virtualStart)
+			sMax = ssMax(sMax, queue.nextDispatchR)
-			estimatedWorkInProgress := qs.estimatedServiceSeconds * float64(queue.seatsInUse)
+			estimatedWorkInProgress := SeatsTimesDuration(float64(queue.seatsInUse), qs.estimatedServiceDuration)
-			dsMin = math.Min(dsMin, queue.virtualStart-estimatedWorkInProgress)
+			dsMin = ssMin(dsMin, queue.nextDispatchR-estimatedWorkInProgress)
-			dsMax = math.Max(dsMax, queue.virtualStart-estimatedWorkInProgress)
+			dsMax = ssMax(dsMax, queue.nextDispatchR-estimatedWorkInProgress)
-			currentVirtualFinish := queue.virtualStart + qs.estimatedServiceSeconds*float64(oldestWaiting.Seats())
+			currentVirtualFinish := queue.nextDispatchR + SeatsTimesDuration(float64(oldestWaiting.Seats()), qs.estimatedServiceDuration)
 			klog.V(11).InfoS("Considering queue to dispatch", "queueSet", qs.qCfg.Name, "queue", qs.robinIndex, "finishR", currentVirtualFinish)
 			if currentVirtualFinish < minVirtualFinish {
 				minVirtualFinish = currentVirtualFinish
@@ -743,13 +747,27 @@ func (qs *queueSet) findDispatchQueueLocked() *queue {
 	// win in the case that the virtual finish times are the same
 	qs.robinIndex = minIndex
 
-	if minQueue.virtualStart < oldestReqFromMinQueue.arrivalR {
+	if minQueue.nextDispatchR < oldestReqFromMinQueue.arrivalR {
-		klog.ErrorS(errors.New("dispatch before arrival"), "Inconceivable!", "QS", qs.qCfg.Name, "queue", minQueue.index, "dispatchR", minQueue.virtualStart, "request", oldestReqFromMinQueue)
+		klog.ErrorS(errors.New("dispatch before arrival"), "Inconceivable!", "QS", qs.qCfg.Name, "queue", minQueue.index, "dispatchR", minQueue.nextDispatchR, "request", oldestReqFromMinQueue)
 	}
-	metrics.SetDispatchMetrics(qs.qCfg.Name, qs.virtualTime, minQueue.virtualStart, sMin, sMax, dsMin, dsMax)
+	metrics.SetDispatchMetrics(qs.qCfg.Name, qs.currentR.ToFloat(), minQueue.nextDispatchR.ToFloat(), sMin.ToFloat(), sMax.ToFloat(), dsMin.ToFloat(), dsMax.ToFloat())
 	return minQueue
 }
 
+func ssMin(a, b SeatSeconds) SeatSeconds {
+	if a > b {
+		return b
+	}
+	return a
+}
+
+func ssMax(a, b SeatSeconds) SeatSeconds {
+	if a < b {
+		return b
+	}
+	return a
+}
+
 // finishRequestAndDispatchAsMuchAsPossible is a convenience method
 // which calls finishRequest for a given request and then dispatches
 // as many requests as possible.  This is all of what needs to be done
@@ -773,7 +791,7 @@ func (qs *queueSet) finishRequestLocked(r *request) {
 	metrics.AddRequestsExecuting(r.ctx, qs.qCfg.Name, r.fsName, -1)
 	qs.obsPair.RequestsExecuting.Add(-1)
 
-	S := now.Sub(r.startTime).Seconds()
+	actualServiceDuration := now.Sub(r.startTime)
 
 	// TODO: for now we keep the logic localized so it is easier to see
 	//  how the counters are tracked for queueset and queue, in future we
@@ -794,11 +812,11 @@ func (qs *queueSet) finishRequestLocked(r *request) {
 			releaseSeatsLocked()
 			if !klog.V(6).Enabled() {
 			} else if r.queue != nil {
-				klog.Infof("QS(%s) at r=%s v=%.9fss: request %#+v %#+v finished all use of %d seats, adjusted queue %d start R to %.9fss due to service time %.9fs, queue will have %d requests, %d seats waiting & %d requests occupying %d seats",
+				klog.Infof("QS(%s) at t=%s R=%v: request %#+v %#+v finished all use of %d seats, adjusted queue %d start R to %v due to service time %.9fs, queue will have %d requests, %d seats waiting & %d requests occupying %d seats",
-					qs.qCfg.Name, now.Format(nsTimeFmt), qs.virtualTime, r.descr1, r.descr2, r.workEstimate.InitialSeats, r.queue.index,
+					qs.qCfg.Name, now.Format(nsTimeFmt), qs.currentR, r.descr1, r.descr2, r.workEstimate.InitialSeats, r.queue.index,
-					r.queue.virtualStart, S, r.queue.requests.Length(), r.queue.requests.SeatsSum(), r.queue.requestsExecuting, r.queue.seatsInUse)
+					r.queue.nextDispatchR, actualServiceDuration.Seconds(), r.queue.requests.Length(), r.queue.requests.SeatsSum(), r.queue.requestsExecuting, r.queue.seatsInUse)
 			} else {
-				klog.Infof("QS(%s) at r=%s v=%.9fss: request %#+v %#+v finished all use of %d seats, qs will have %d requests occupying %d seats", qs.qCfg.Name, now.Format(nsTimeFmt), qs.virtualTime, r.descr1, r.descr2, r.workEstimate.InitialSeats, qs.totRequestsExecuting, qs.totSeatsInUse)
+				klog.Infof("QS(%s) at t=%s R=%v: request %#+v %#+v finished all use of %d seats, qs will have %d requests occupying %d seats", qs.qCfg.Name, now.Format(nsTimeFmt), qs.currentR, r.descr1, r.descr2, r.workEstimate.InitialSeats, qs.totRequestsExecuting, qs.totSeatsInUse)
 			}
 			return
 		}
@@ -806,11 +824,11 @@ func (qs *queueSet) finishRequestLocked(r *request) {
 		additionalLatency := r.workEstimate.AdditionalLatency
 		if !klog.V(6).Enabled() {
 		} else if r.queue != nil {
-			klog.Infof("QS(%s) at r=%s v=%.9fss: request %#+v %#+v finished main use but lingering on %d seats for %v seconds, adjusted queue %d start R to %.9fss due to service time %.9fs, queue will have %d requests waiting & %d executing, still has %d seats waiting & %d executing",
+			klog.Infof("QS(%s) at t=%s R=%v: request %#+v %#+v finished main use but lingering on %d seats for %v seconds, adjusted queue %d start R to %v due to service time %.9fs, queue will have %d requests waiting & %d executing, still has %d seats waiting & %d executing",
-				qs.qCfg.Name, now.Format(nsTimeFmt), qs.virtualTime, r.descr1, r.descr2, r.workEstimate.InitialSeats, additionalLatency.Seconds(), r.queue.index,
+				qs.qCfg.Name, now.Format(nsTimeFmt), qs.currentR, r.descr1, r.descr2, r.workEstimate.InitialSeats, additionalLatency.Seconds(), r.queue.index,
-				r.queue.virtualStart, S, r.queue.requests.Length(), r.queue.requestsExecuting, r.queue.requests.SeatsSum(), r.queue.seatsInUse)
+				r.queue.nextDispatchR, actualServiceDuration.Seconds(), r.queue.requests.Length(), r.queue.requestsExecuting, r.queue.requests.SeatsSum(), r.queue.seatsInUse)
 		} else {
-			klog.Infof("QS(%s) at r=%s v=%.9fss: request %#+v %#+v finished main use but lingering on %d seats for %v seconds, qs will have %d requests occupying %d seats", qs.qCfg.Name, now.Format(nsTimeFmt), qs.virtualTime, r.descr1, r.descr2, r.workEstimate.InitialSeats, additionalLatency.Seconds(), qs.totRequestsExecuting, qs.totSeatsInUse)
+			klog.Infof("QS(%s) at t=%s R=%v: request %#+v %#+v finished main use but lingering on %d seats for %v seconds, qs will have %d requests occupying %d seats", qs.qCfg.Name, now.Format(nsTimeFmt), qs.currentR, r.descr1, r.descr2, r.workEstimate.InitialSeats, additionalLatency.Seconds(), qs.totRequestsExecuting, qs.totSeatsInUse)
 		}
 		// EventAfterDuration will execute the event func in a new goroutine,
 		// so the seats allocated to this request will be released after
@@ -823,11 +841,11 @@ func (qs *queueSet) finishRequestLocked(r *request) {
 			releaseSeatsLocked()
 			if !klog.V(6).Enabled() {
 			} else if r.queue != nil {
-				klog.Infof("QS(%s) at r=%s v=%.9fss: request %#+v %#+v finished lingering on %d seats, queue %d will have %d requests, %d seats waiting & %d requests occupying %d seats",
+				klog.Infof("QS(%s) at t=%s R=%v: request %#+v %#+v finished lingering on %d seats, queue %d will have %d requests, %d seats waiting & %d requests occupying %d seats",
-					qs.qCfg.Name, now.Format(nsTimeFmt), qs.virtualTime, r.descr1, r.descr2, r.workEstimate.InitialSeats, r.queue.index,
+					qs.qCfg.Name, now.Format(nsTimeFmt), qs.currentR, r.descr1, r.descr2, r.workEstimate.InitialSeats, r.queue.index,
 					r.queue.requests.Length(), r.queue.requests.SeatsSum(), r.queue.requestsExecuting, r.queue.seatsInUse)
 			} else {
-				klog.Infof("QS(%s) at r=%s v=%.9fss: request %#+v %#+v finished lingering on %d seats, qs will have %d requests occupying %d seats", qs.qCfg.Name, now.Format(nsTimeFmt), qs.virtualTime, r.descr1, r.descr2, r.workEstimate.InitialSeats, qs.totRequestsExecuting, qs.totSeatsInUse)
+				klog.Infof("QS(%s) at t=%s R=%v: request %#+v %#+v finished lingering on %d seats, qs will have %d requests occupying %d seats", qs.qCfg.Name, now.Format(nsTimeFmt), qs.currentR, r.descr1, r.descr2, r.workEstimate.InitialSeats, qs.totRequestsExecuting, qs.totSeatsInUse)
 			}
 			qs.dispatchAsMuchAsPossibleLocked()
 		}, additionalLatency)
@@ -839,7 +857,7 @@ func (qs *queueSet) finishRequestLocked(r *request) {
 
 		// When a request finishes being served, and the actual service time was S,
 		// the queue’s start R is decremented by (G - S)*width.
-		r.queue.virtualStart -= (qs.estimatedServiceSeconds - S) * float64(r.Seats())
+		r.queue.nextDispatchR -= SeatsTimesDuration(float64(r.Seats()), qs.estimatedServiceDuration-actualServiceDuration)
 		qs.boundNextDispatch(r.queue)
 	}
 }
@@ -857,11 +875,11 @@ func (qs *queueSet) boundNextDispatch(queue *queue) {
 		return
 	}
 	var virtualStartBound = oldestReqFromMinQueue.arrivalR
-	if queue.virtualStart < virtualStartBound {
+	if queue.nextDispatchR < virtualStartBound {
 		if klog.V(4).Enabled() {
-			klog.InfoS("AntiWindup tweaked queue", "QS", qs.qCfg.Name, "queue", queue.index, "time", qs.clock.Now().Format(nsTimeFmt), "requestDescr1", oldestReqFromMinQueue.descr1, "requestDescr2", oldestReqFromMinQueue.descr2, "newVirtualStart", virtualStartBound, "deltaVirtualStart", (virtualStartBound - queue.virtualStart))
+			klog.InfoS("AntiWindup tweaked queue", "QS", qs.qCfg.Name, "queue", queue.index, "time", qs.clock.Now().Format(nsTimeFmt), "requestDescr1", oldestReqFromMinQueue.descr1, "requestDescr2", oldestReqFromMinQueue.descr2, "newVirtualStart", virtualStartBound, "deltaVirtualStart", (virtualStartBound - queue.nextDispatchR))
 		}
-		queue.virtualStart = virtualStartBound
+		queue.nextDispatchR = virtualStartBound
 	}
 }
 

staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/queueset/queueset_test.go

@@ -247,7 +247,7 @@ type uniformScenarioThread struct {
 }
 
 func (ust *uniformScenarioThread) start() {
-	initialDelay := time.Duration(11*ust.j + 2*ust.i)
+	initialDelay := time.Duration(90*ust.j + 20*ust.i)
 	if ust.uc.split && ust.j >= ust.uc.nThreads/2 {
 		initialDelay += ust.uss.evalDuration / 2
 		ust.nCalls = ust.nCalls / 2
@@ -601,7 +601,7 @@ func TestUniformFlowsHandSize3(t *testing.T) {
 		concurrencyLimit:       4,
 		evalDuration:           time.Second * 60,
 		expectedFair:           []bool{true},
-		expectedFairnessMargin: []float64{0.01},
+		expectedFairnessMargin: []float64{0.03},
 		expectAllRequests:      true,
 		evalInqueueMetrics:     true,
 		evalExecutingMetrics:   true,
@@ -647,6 +647,46 @@ func TestDifferentFlowsExpectEqual(t *testing.T) {
 	}.exercise(t)
 }
 
+// TestSeatSecondsRollover demonstrates that SeatSeconds overflow can cause bad stuff to happen.
+func TestSeatSecondsRollover(t *testing.T) {
+	metrics.Register()
+	now := time.Now()
+
+	const Quarter = 91 * 24 * time.Hour
+
+	clk, counter := testeventclock.NewFake(now, 0, nil)
+	qsf := newTestableQueueSetFactory(clk, countingPromiseFactoryFactory(counter))
+	qCfg := fq.QueuingConfig{
+		Name:             "TestSeatSecondsRollover",
+		DesiredNumQueues: 9,
+		QueueLengthLimit: 8,
+		HandSize:         1,
+		RequestWaitLimit: 40 * Quarter,
+	}
+	qsc, err := qsf.BeginConstruction(qCfg, newObserverPair(clk))
+	if err != nil {
+		t.Fatal(err)
+	}
+	qs := qsc.Complete(fq.DispatchingConfig{ConcurrencyLimit: 2000})
+
+	uniformScenario{name: qCfg.Name,
+		qs: qs,
+		clients: []uniformClient{
+			newUniformClient(1001001001, 8, 20, Quarter, Quarter).seats(500),
+			newUniformClient(2002002002, 7, 30, Quarter, Quarter/2).seats(500),
+		},
+		concurrencyLimit:       2000,
+		evalDuration:           Quarter * 40,
+		expectedFair:           []bool{false},
+		expectedFairnessMargin: []float64{0.01},
+		expectAllRequests:      true,
+		evalInqueueMetrics:     true,
+		evalExecutingMetrics:   true,
+		clk:                    clk,
+		counter:                counter,
+	}.exercise(t)
+}
+
 func TestDifferentFlowsExpectUnequal(t *testing.T) {
 	metrics.Register()
 	now := time.Now()
@@ -1073,7 +1113,7 @@ func TestTotalRequestsExecutingWithPanic(t *testing.T) {
 }
 
 func TestFindDispatchQueueLocked(t *testing.T) {
-	var G float64 = 0.003
+	const G = 3 * time.Millisecond
 	tests := []struct {
 		name                    string
 		robinIndex              int
@@ -1092,13 +1132,13 @@ func TestFindDispatchQueueLocked(t *testing.T) {
 			robinIndex:       -1,
 			queues: []*queue{
 				{
-					virtualStart: 200,
+					nextDispatchR: SeatsTimesDuration(1, 200*time.Second),
 					requests: newFIFO(
 						&request{workEstimate: fcrequest.WorkEstimate{InitialSeats: 1}},
 					),
 				},
 				{
-					virtualStart: 100,
+					nextDispatchR: SeatsTimesDuration(1, 100*time.Second),
 					requests: newFIFO(
 						&request{workEstimate: fcrequest.WorkEstimate{InitialSeats: 1}},
 					),
@@ -1115,7 +1155,7 @@ func TestFindDispatchQueueLocked(t *testing.T) {
 			robinIndex:       -1,
 			queues: []*queue{
 				{
-					virtualStart: 200,
+					nextDispatchR: SeatsTimesDuration(1, 200*time.Second),
 					requests: newFIFO(
 						&request{workEstimate: fcrequest.WorkEstimate{InitialSeats: 1}},
 					),
@@ -1132,13 +1172,13 @@ func TestFindDispatchQueueLocked(t *testing.T) {
 			robinIndex:       -1,
 			queues: []*queue{
 				{
-					virtualStart: 200,
+					nextDispatchR: SeatsTimesDuration(1, 200*time.Second),
 					requests: newFIFO(
 						&request{workEstimate: fcrequest.WorkEstimate{InitialSeats: 50}},
 					),
 				},
 				{
-					virtualStart: 100,
+					nextDispatchR: SeatsTimesDuration(1, 100*time.Second),
 					requests: newFIFO(
 						&request{workEstimate: fcrequest.WorkEstimate{InitialSeats: 25}},
 					),
@@ -1155,13 +1195,13 @@ func TestFindDispatchQueueLocked(t *testing.T) {
 			robinIndex:       -1,
 			queues: []*queue{
 				{
-					virtualStart: 200,
+					nextDispatchR: SeatsTimesDuration(1, 200*time.Second),
 					requests: newFIFO(
 						&request{workEstimate: fcrequest.WorkEstimate{InitialSeats: 10}},
 					),
 				},
 				{
-					virtualStart: 100,
+					nextDispatchR: SeatsTimesDuration(1, 100*time.Second),
 					requests: newFIFO(
 						&request{workEstimate: fcrequest.WorkEstimate{InitialSeats: 25}},
 					),
@@ -1178,13 +1218,13 @@ func TestFindDispatchQueueLocked(t *testing.T) {
 			robinIndex:       -1,
 			queues: []*queue{
 				{
-					virtualStart: 200,
+					nextDispatchR: SeatsTimesDuration(1, 200*time.Second),
 					requests: newFIFO(
 						&request{workEstimate: fcrequest.WorkEstimate{InitialSeats: 10}},
 					),
 				},
 				{
-					virtualStart: 100,
+					nextDispatchR: SeatsTimesDuration(1, 100*time.Second),
 					requests: newFIFO(
 						&request{workEstimate: fcrequest.WorkEstimate{InitialSeats: 25}},
 					),
@@ -1204,10 +1244,10 @@ func TestFindDispatchQueueLocked(t *testing.T) {
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
 			qs := &queueSet{
-				estimatedServiceSeconds: G,
+				estimatedServiceDuration: G,
-				robinIndex:              test.robinIndex,
+				robinIndex:               test.robinIndex,
-				totSeatsInUse:           test.totSeatsInUse,
+				totSeatsInUse:            test.totSeatsInUse,
-				qCfg:                    fq.QueuingConfig{Name: "TestSelectQueueLocked/" + test.name},
+				qCfg:                     fq.QueuingConfig{Name: "TestSelectQueueLocked/" + test.name},
 				dCfg: fq.DispatchingConfig{
 					ConcurrencyLimit: test.concurrencyLimit,
 				},

staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/queueset/types.go

@@ -62,7 +62,7 @@ type request struct {
 	arrivalTime time.Time
 
 	// arrivalR is R(arrivalTime).  R is, confusingly, also called "virtual time".
-	arrivalR float64
+	arrivalR SeatSeconds
 
 	// descr1 and descr2 are not used in any logic but they appear in
 	// log messages
@@ -84,9 +84,9 @@ type queue struct {
 	// The requests not yet executing in the real world are stored in a FIFO list.
 	requests fifo
 
-	// virtualStart is the "virtual time" (R progress meter reading) at
+	// nextDispatchR is the R progress meter reading at
 	// which the next request will be dispatched in the virtual world.
-	virtualStart float64
+	nextDispatchR SeatSeconds
 
 	// requestsExecuting is the count in the real world
 	requestsExecuting int
@@ -130,7 +130,7 @@ func (q *queue) dump(includeDetails bool) debug.QueueDump {
 		return true
 	})
 	return debug.QueueDump{
-		VirtualStart:      q.virtualStart,
+		VirtualStart:      q.nextDispatchR.ToFloat(), // TODO: change QueueDump to use SeatSeconds
 		Requests:          digest,
 		ExecutingRequests: q.requestsExecuting,
 		SeatsInUse:        q.seatsInUse,