From 80ca6a4ae6ff571c32962a7155efd55edefff9e6 Mon Sep 17 00:00:00 2001
From: Mike Spreitzer <mspreitz@us.ibm.com>
Date: Fri, 6 Aug 2021 02:06:43 -0400
Subject: [PATCH] Some cleanup of the package for event clocks

Rename from `clock` to `eventclock`.

Simplify by removing the prohibition on an EventFunc suspending and
resuming activity.

Remove "EventClock" from names to avoid stuttering.

Start to consolidate test code under fairqueuing/testing/.
---
 .../pkg/util/flowcontrol/apf_filter.go        |  8 ++--
 .../{clock => eventclock}/interface.go        |  4 +-
 .../fairqueuing/{clock => eventclock}/real.go | 10 ++--
 .../real_event_clock_test.go                  |  4 +-
 .../fairqueuing/promise/promise_test.go       |  4 +-
 .../fairqueuing/queueset/queueset.go          |  9 ++--
 .../fairqueuing/queueset/queueset_test.go     | 34 ++++++--------
 .../testing => testing/eventclock}/fake.go    | 47 ++++++++++---------
 .../eventclock}/fake_event_clock_test.go      | 12 ++---
 vendor/modules.txt                            |  2 +-
 10 files changed, 65 insertions(+), 69 deletions(-)
 rename staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/{clock => eventclock}/interface.go (97%)
 rename staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/{clock => eventclock}/real.go (82%)
 rename staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/{clock => eventclock}/real_event_clock_test.go (97%)
 rename staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/{clock/testing => testing/eventclock}/fake.go (84%)
 rename staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/{clock/testing => testing/eventclock}/fake_event_clock_test.go (92%)

diff --git a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/apf_filter.go b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/apf_filter.go
index f9a287eab2d..11e709ca66d 100644
--- a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/apf_filter.go
+++ b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/apf_filter.go
@@ -24,12 +24,12 @@ import (
 	"k8s.io/apiserver/pkg/server/mux"
 	"k8s.io/apiserver/pkg/util/flowcontrol/counter"
 	fq "k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing"
-	fairqueuingclock "k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock"
+	"k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/eventclock"
 	fqs "k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/queueset"
 	"k8s.io/apiserver/pkg/util/flowcontrol/metrics"
 	kubeinformers "k8s.io/client-go/informers"
 	"k8s.io/klog/v2"
-	utilclock "k8s.io/utils/clock"
+	"k8s.io/utils/clock"
 
 	flowcontrol "k8s.io/api/flowcontrol/v1beta1"
 	flowcontrolclient "k8s.io/client-go/kubernetes/typed/flowcontrol/v1beta1"
@@ -84,7 +84,7 @@ func New(
 	requestWaitLimit time.Duration,
 ) Interface {
 	grc := counter.NoOp{}
-	clk := fairqueuingclock.RealEventClock{}
+	clk := eventclock.Real{}
 	return NewTestable(TestableConfig{
 		Name:                   "Controller",
 		Clock:                  clk,
@@ -105,7 +105,7 @@ type TestableConfig struct {
 	Name string
 
 	// Clock to use in timing deliberate delays
-	Clock utilclock.PassiveClock
+	Clock clock.PassiveClock
 
 	// AsFieldManager is the string to use in the metadata for
 	// server-side apply.  Normally this is
diff --git a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/interface.go b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/eventclock/interface.go
similarity index 97%
rename from staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/interface.go
rename to staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/eventclock/interface.go
index 9dbb658a835..58f88b99246 100644
--- a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/interface.go
+++ b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/eventclock/interface.go
@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package clock
+package eventclock
 
 import (
 	"time"
@@ -31,7 +31,7 @@ type EventFunc func(time.Time)
 // advanced.  The timing paradigm is invoking EventFuncs rather than
 // synchronizing through channels, so that the fake clock has a handle
 // on when associated activity is done.
-type EventClock interface {
+type Interface interface {
 	baseclock.PassiveClock
 
 	// Sleep returns after the given duration (or more).
diff --git a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/real.go b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/eventclock/real.go
similarity index 82%
rename from staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/real.go
rename to staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/eventclock/real.go
index 1ad1a34d4b3..d567a0f45e6 100644
--- a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/real.go
+++ b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/eventclock/real.go
@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package clock
+package eventclock
 
 import (
 	"time"
@@ -23,12 +23,14 @@ import (
 )
 
 // RealEventClock fires event on real world time
-type RealEventClock struct {
+type Real struct {
 	clock.RealClock
 }
 
+var _ Interface = Real{}
+
 // EventAfterDuration schedules an EventFunc
-func (RealEventClock) EventAfterDuration(f EventFunc, d time.Duration) {
+func (Real) EventAfterDuration(f EventFunc, d time.Duration) {
 	ch := time.After(d)
 	go func() {
 		t := <-ch
@@ -37,6 +39,6 @@ func (RealEventClock) EventAfterDuration(f EventFunc, d time.Duration) {
 }
 
 // EventAfterTime schedules an EventFunc
-func (r RealEventClock) EventAfterTime(f EventFunc, t time.Time) {
+func (r Real) EventAfterTime(f EventFunc, t time.Time) {
 	r.EventAfterDuration(f, time.Until(t))
 }
diff --git a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/real_event_clock_test.go b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/eventclock/real_event_clock_test.go
similarity index 97%
rename from staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/real_event_clock_test.go
rename to staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/eventclock/real_event_clock_test.go
index 8e9331a4254..0a4e44bed05 100644
--- a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/real_event_clock_test.go
+++ b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/eventclock/real_event_clock_test.go
@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package clock
+package eventclock
 
 import (
 	"math/rand"
@@ -24,7 +24,7 @@ import (
 )
 
 func TestRealEventClock(t *testing.T) {
-	ec := RealEventClock{}
+	ec := Real{}
 	var numDone int32
 	now := ec.Now()
 	const batchSize = 100
diff --git a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/promise/promise_test.go b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/promise/promise_test.go
index 90eed0a9f92..83f182c3ea8 100644
--- a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/promise/promise_test.go
+++ b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/promise/promise_test.go
@@ -22,12 +22,12 @@ import (
 	"testing"
 	"time"
 
-	testclock "k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/testing"
+	testclock "k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/testing/eventclock"
 )
 
 func TestLockingWriteOnce(t *testing.T) {
 	now := time.Now()
-	clock, counter := testclock.NewFakeEventClock(now, 0, nil)
+	clock, counter := testclock.NewFake(now, 0, nil)
 	var lock sync.Mutex
 	wr := NewWriteOnce(&lock, counter)
 	var gots int32
diff --git a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/queueset/queueset.go b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/queueset/queueset.go
index cd9fda988cb..6b9937a3b47 100644
--- a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/queueset/queueset.go
+++ b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/queueset/queueset.go
@@ -27,7 +27,7 @@ import (
 	"k8s.io/apiserver/pkg/util/flowcontrol/counter"
 	"k8s.io/apiserver/pkg/util/flowcontrol/debug"
 	fq "k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing"
-	fairqueuingclock "k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock"
+	"k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/eventclock"
 	"k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/promise"
 	"k8s.io/apiserver/pkg/util/flowcontrol/metrics"
 	fqrequest "k8s.io/apiserver/pkg/util/flowcontrol/request"
@@ -37,7 +37,6 @@ import (
 	// The following hack is needed to work around a tooling deficiency.
 	// Packages imported only for test code are not included in vendor.
 	// See https://kubernetes.slack.com/archives/C0EG7JC6T/p1626985671458800?thread_ts=1626983387.450800&cid=C0EG7JC6T
-	// The need for this hack will be removed when we make queueset use an EventClock rather than a PassiveClock.
 	_ "k8s.io/utils/clock/testing"
 )
 
@@ -47,7 +46,7 @@ const nsTimeFmt = "2006-01-02 15:04:05.000000000"
 // queueSetFactory makes QueueSet objects.
 type queueSetFactory struct {
 	counter counter.GoRoutineCounter
-	clock   fairqueuingclock.EventClock
+	clock   eventclock.Interface
 }
 
 // `*queueSetCompleter` implements QueueSetCompleter.  Exactly one of
@@ -70,7 +69,7 @@ type queueSetCompleter struct {
 // not end in "Locked" either acquires the lock or does not care about
 // locking.
 type queueSet struct {
-	clock                fairqueuingclock.EventClock
+	clock                eventclock.Interface
 	counter              counter.GoRoutineCounter
 	estimatedServiceTime float64
 	obsPair              metrics.TimedObserverPair
@@ -120,7 +119,7 @@ type queueSet struct {
 }
 
 // NewQueueSetFactory creates a new QueueSetFactory object
-func NewQueueSetFactory(c fairqueuingclock.EventClock, counter counter.GoRoutineCounter) fq.QueueSetFactory {
+func NewQueueSetFactory(c eventclock.Interface, counter counter.GoRoutineCounter) fq.QueueSetFactory {
 	return &queueSetFactory{
 		counter: counter,
 		clock:   c,
diff --git a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/queueset/queueset_test.go b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/queueset/queueset_test.go
index 6ae72c43cbd..44b36d22272 100644
--- a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/queueset/queueset_test.go
+++ b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/queueset/queueset_test.go
@@ -31,8 +31,8 @@ import (
 
 	"k8s.io/apiserver/pkg/util/flowcontrol/counter"
 	fq "k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing"
-	fqclocktest "k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/testing"
 	test "k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/testing"
+	testeventclock "k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/testing/eventclock"
 	"k8s.io/apiserver/pkg/util/flowcontrol/metrics"
 	fcrequest "k8s.io/apiserver/pkg/util/flowcontrol/request"
 	"k8s.io/klog/v2"
@@ -133,7 +133,7 @@ type uniformScenario struct {
 	expectAllRequests                        bool
 	evalInqueueMetrics, evalExecutingMetrics bool
 	rejectReason                             string
-	clk                                      *fqclocktest.FakeEventClock
+	clk                                      *testeventclock.Fake
 	counter                                  counter.GoRoutineCounter
 }
 
@@ -211,16 +211,10 @@ func (ust *uniformScenarioThread) start() {
 	ust.uss.clk.EventAfterDuration(ust.genCallK(0), initialDelay)
 }
 
-// generates an EventFunc that forks a goroutine to do call k
+// generates an EventFunc that does call k
 func (ust *uniformScenarioThread) genCallK(k int) func(time.Time) {
 	return func(time.Time) {
-		// As an EventFunc, this has to return without waiting
-		// for time to pass, and so cannot do callK(k) itself.
-		ust.uss.counter.Add(1)
-		go func() {
-			ust.callK(k)
-			ust.uss.counter.Add(-1)
-		}()
+		ust.callK(k)
 	}
 }
 
@@ -367,7 +361,7 @@ func init() {
 func TestNoRestraint(t *testing.T) {
 	metrics.Register()
 	now := time.Now()
-	clk, counter := fqclocktest.NewFakeEventClock(now, 0, nil)
+	clk, counter := testeventclock.NewFake(now, 0, nil)
 	nrc, err := test.NewNoRestraintFactory().BeginConstruction(fq.QueuingConfig{}, newObserverPair(clk))
 	if err != nil {
 		t.Fatal(err)
@@ -393,7 +387,7 @@ func TestUniformFlowsHandSize1(t *testing.T) {
 	metrics.Register()
 	now := time.Now()
 
-	clk, counter := fqclocktest.NewFakeEventClock(now, 0, nil)
+	clk, counter := testeventclock.NewFake(now, 0, nil)
 	qsf := NewQueueSetFactory(clk, counter)
 	qCfg := fq.QueuingConfig{
 		Name:             "TestUniformFlowsHandSize1",
@@ -430,7 +424,7 @@ func TestUniformFlowsHandSize3(t *testing.T) {
 	metrics.Register()
 	now := time.Now()
 
-	clk, counter := fqclocktest.NewFakeEventClock(now, 0, nil)
+	clk, counter := testeventclock.NewFake(now, 0, nil)
 	qsf := NewQueueSetFactory(clk, counter)
 	qCfg := fq.QueuingConfig{
 		Name:             "TestUniformFlowsHandSize3",
@@ -466,7 +460,7 @@ func TestDifferentFlowsExpectEqual(t *testing.T) {
 	metrics.Register()
 	now := time.Now()
 
-	clk, counter := fqclocktest.NewFakeEventClock(now, 0, nil)
+	clk, counter := testeventclock.NewFake(now, 0, nil)
 	qsf := NewQueueSetFactory(clk, counter)
 	qCfg := fq.QueuingConfig{
 		Name:             "DiffFlowsExpectEqual",
@@ -503,7 +497,7 @@ func TestDifferentFlowsExpectUnequal(t *testing.T) {
 	metrics.Register()
 	now := time.Now()
 
-	clk, counter := fqclocktest.NewFakeEventClock(now, 0, nil)
+	clk, counter := testeventclock.NewFake(now, 0, nil)
 	qsf := NewQueueSetFactory(clk, counter)
 	qCfg := fq.QueuingConfig{
 		Name:             "DiffFlowsExpectUnequal",
@@ -540,7 +534,7 @@ func TestWindup(t *testing.T) {
 	metrics.Register()
 	now := time.Now()
 
-	clk, counter := fqclocktest.NewFakeEventClock(now, 0, nil)
+	clk, counter := testeventclock.NewFake(now, 0, nil)
 	qsf := NewQueueSetFactory(clk, counter)
 	qCfg := fq.QueuingConfig{
 		Name:             "TestWindup",
@@ -576,7 +570,7 @@ func TestDifferentFlowsWithoutQueuing(t *testing.T) {
 	metrics.Register()
 	now := time.Now()
 
-	clk, counter := fqclocktest.NewFakeEventClock(now, 0, nil)
+	clk, counter := testeventclock.NewFake(now, 0, nil)
 	qsf := NewQueueSetFactory(clk, counter)
 	qCfg := fq.QueuingConfig{
 		Name:             "TestDifferentFlowsWithoutQueuing",
@@ -609,7 +603,7 @@ func TestTimeout(t *testing.T) {
 	metrics.Register()
 	now := time.Now()
 
-	clk, counter := fqclocktest.NewFakeEventClock(now, 0, nil)
+	clk, counter := testeventclock.NewFake(now, 0, nil)
 	qsf := NewQueueSetFactory(clk, counter)
 	qCfg := fq.QueuingConfig{
 		Name:             "TestTimeout",
@@ -645,7 +639,7 @@ func TestContextCancel(t *testing.T) {
 	metrics.Register()
 	metrics.Reset()
 	now := time.Now()
-	clk, counter := fqclocktest.NewFakeEventClock(now, 0, nil)
+	clk, counter := testeventclock.NewFake(now, 0, nil)
 	qsf := NewQueueSetFactory(clk, counter)
 	qCfg := fq.QueuingConfig{
 		Name:             "TestContextCancel",
@@ -724,7 +718,7 @@ func TestTotalRequestsExecutingWithPanic(t *testing.T) {
 	metrics.Register()
 	metrics.Reset()
 	now := time.Now()
-	clk, counter := fqclocktest.NewFakeEventClock(now, 0, nil)
+	clk, counter := testeventclock.NewFake(now, 0, nil)
 	qsf := NewQueueSetFactory(clk, counter)
 	qCfg := fq.QueuingConfig{
 		Name:             "TestTotalRequestsExecutingWithPanic",
diff --git a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/testing/fake.go b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/testing/eventclock/fake.go
similarity index 84%
rename from staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/testing/fake.go
rename to staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/testing/eventclock/fake.go
index 5ef43a2d898..9f672c27c36 100644
--- a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/testing/fake.go
+++ b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/testing/eventclock/fake.go
@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package testing
+package eventclock
 
 import (
 	"container/heap"
@@ -27,7 +27,7 @@ import (
 	baseclocktest "k8s.io/utils/clock/testing"
 
 	"k8s.io/apiserver/pkg/util/flowcontrol/counter"
-	"k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock"
+	"k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/eventclock"
 	"k8s.io/klog/v2"
 )
 
@@ -65,9 +65,9 @@ func (wgc *waitGroupCounter) Wait() {
 	wgc.wg.Wait()
 }
 
-// FakeEventClock is one whose time does not pass implicitly but
+// Fake is one whose time does not pass implicitly but
 // rather is explicitly set by invocations of its SetTime method.
-// Each FakeEventClock has an associated GoRoutineCounter that is
+// Each Fake has an associated GoRoutineCounter that is
 // used to track associated activity.
 // For the EventAfterDuration and EventAfterTime methods,
 // the clock itself counts the start and stop of the EventFunc
@@ -75,10 +75,7 @@ func (wgc *waitGroupCounter) Wait() {
 // resume internal to the EventFunc.
 // The Sleep method must only be invoked from a goroutine that is
 // counted in that GoRoutineCounter.
-// The SetTime method does not return until all the triggered
-// EventFuncs return.  Consequently, an EventFunc given to a method
-// of this clock must not wait for this clock to advance.
-type FakeEventClock struct {
+type Fake struct {
 	baseclocktest.FakePassiveClock
 
 	// waiters is a heap of waiting work, sorted by time
@@ -100,21 +97,23 @@ type FakeEventClock struct {
 	rand *rand.Rand
 }
 
+var _ eventclock.Interface = &Fake{}
+
 type eventWaiterHeap []eventWaiter
 
 var _ heap.Interface = (*eventWaiterHeap)(nil)
 
 type eventWaiter struct {
 	targetTime time.Time
-	f          clock.EventFunc
+	f          eventclock.EventFunc
 }
 
-// NewFakeEventClock constructor.  The given `r *rand.Rand` must
+// NewFake constructs a new fake event clock.  The given `r *rand.Rand` must
 // henceforth not be used for any other purpose.  If `r` is nil then a
 // fresh one will be constructed, seeded with the current real time.
 // The clientWG can be `nil` and if not is used to let Run know about
 // additional work that has to complete before time can advance.
-func NewFakeEventClock(t time.Time, fuzz time.Duration, r *rand.Rand) (*FakeEventClock, counter.GoRoutineCounter) {
+func NewFake(t time.Time, fuzz time.Duration, r *rand.Rand) (*Fake, counter.GoRoutineCounter) {
 	grc := &waitGroupCounter{}
 
 	if r == nil {
@@ -123,7 +122,7 @@ func NewFakeEventClock(t time.Time, fuzz time.Duration, r *rand.Rand) (*FakeEven
 		r.Uint64()
 		r.Uint64()
 	}
-	return &FakeEventClock{
+	return &Fake{
 		FakePassiveClock: *baseclocktest.NewFakePassiveClock(t),
 		clientWG:         grc,
 		fuzz:             fuzz,
@@ -133,7 +132,7 @@ func NewFakeEventClock(t time.Time, fuzz time.Duration, r *rand.Rand) (*FakeEven
 
 // GetNextTime returns the next time at which there is work scheduled,
 // and a bool indicating whether there is any such time
-func (fec *FakeEventClock) GetNextTime() (time.Time, bool) {
+func (fec *Fake) GetNextTime() (time.Time, bool) {
 	fec.waitersLock.RLock()
 	defer fec.waitersLock.RUnlock()
 	if len(fec.waiters) > 0 {
@@ -147,7 +146,7 @@ func (fec *FakeEventClock) GetNextTime() (time.Time, bool) {
 // nil and the next time would exceed the limit.  The associated
 // GoRoutineCounter gates the advancing of time.  That is,
 // time is not advanced until all the associated work is finished.
-func (fec *FakeEventClock) Run(limit *time.Time) {
+func (fec *Fake) Run(limit *time.Time) {
 	for {
 		fec.clientWG.Wait()
 		t, ok := fec.GetNextTime()
@@ -161,7 +160,7 @@ func (fec *FakeEventClock) Run(limit *time.Time) {
 // SetTime sets the time and runs to completion all events that should
 // be started by the given time --- including any further events they
 // schedule
-func (fec *FakeEventClock) SetTime(t time.Time) {
+func (fec *Fake) SetTime(t time.Time) {
 	fec.FakePassiveClock.SetTime(t)
 	for {
 		foundSome := false
@@ -172,27 +171,29 @@ func (fec *FakeEventClock) SetTime(t time.Time) {
 			// events to run at that or an earlier time.
 			// Events should not advance the clock.  But just in case they do...
 			now := fec.Now()
-			var wg sync.WaitGroup
 			for len(fec.waiters) > 0 && !now.Before(fec.waiters[0].targetTime) {
 				ew := heap.Pop(&fec.waiters).(eventWaiter)
-				wg.Add(1)
-				go func(f clock.EventFunc) { f(now); wg.Done() }(ew.f)
+				fec.clientWG.Add(1)
+				go func(f eventclock.EventFunc, now time.Time) {
+					f(now)
+					fec.clientWG.Add(-1)
+				}(ew.f, now)
 				foundSome = true
 			}
-			wg.Wait()
 		}()
 		if !foundSome {
 			break
 		}
+		fec.clientWG.Wait()
 	}
 }
 
 // Sleep returns after the given duration has passed.
 // Sleep must only be invoked in a goroutine that is counted
-// in the FakeEventClock's associated GoRoutineCounter.
+// in the Fake's associated GoRoutineCounter.
 // Unlike the base FakeClock's Sleep, this method does not itself advance the clock
 // but rather leaves that up to other actors (e.g., Run).
-func (fec *FakeEventClock) Sleep(duration time.Duration) {
+func (fec *Fake) Sleep(duration time.Duration) {
 	doneCh := make(chan struct{})
 	fec.EventAfterDuration(func(time.Time) {
 		fec.clientWG.Add(1)
@@ -204,7 +205,7 @@ func (fec *FakeEventClock) Sleep(duration time.Duration) {
 
 // EventAfterDuration schedules the given function to be invoked once
 // the given duration has passed.
-func (fec *FakeEventClock) EventAfterDuration(f clock.EventFunc, d time.Duration) {
+func (fec *Fake) EventAfterDuration(f eventclock.EventFunc, d time.Duration) {
 	fec.waitersLock.Lock()
 	defer fec.waitersLock.Unlock()
 	now := fec.Now()
@@ -214,7 +215,7 @@ func (fec *FakeEventClock) EventAfterDuration(f clock.EventFunc, d time.Duration
 
 // EventAfterTime schedules the given function to be invoked once
 // the given time has arrived.
-func (fec *FakeEventClock) EventAfterTime(f clock.EventFunc, t time.Time) {
+func (fec *Fake) EventAfterTime(f eventclock.EventFunc, t time.Time) {
 	fec.waitersLock.Lock()
 	defer fec.waitersLock.Unlock()
 	fd := time.Duration(float32(fec.fuzz) * fec.rand.Float32())
diff --git a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/testing/fake_event_clock_test.go b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/testing/eventclock/fake_event_clock_test.go
similarity index 92%
rename from staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/testing/fake_event_clock_test.go
rename to staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/testing/eventclock/fake_event_clock_test.go
index e6fd9b5f804..ef451aa80fa 100644
--- a/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock/testing/fake_event_clock_test.go
+++ b/staging/src/k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/testing/eventclock/fake_event_clock_test.go
@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package testing
+package eventclock
 
 import (
 	"math/rand"
@@ -22,11 +22,11 @@ import (
 	"testing"
 	"time"
 
-	"k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock"
+	"k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/eventclock"
 )
 
 type TestableEventClock interface {
-	clock.EventClock
+	eventclock.Interface
 	SetTime(time.Time)
 	Run(*time.Time)
 }
@@ -122,10 +122,10 @@ func exerciseSettablePassiveClock(t *testing.T, pc TestableEventClock) {
 	}
 }
 
-func TestFakeEventClock(t *testing.T) {
+func TestFake(t *testing.T) {
 	startTime := time.Now()
-	fec, _ := NewFakeEventClock(startTime, 0, nil)
+	fec, _ := NewFake(startTime, 0, nil)
 	exerciseTestableEventClock(t, fec, 0)
-	fec, _ = NewFakeEventClock(startTime, time.Second, nil)
+	fec, _ = NewFake(startTime, time.Second, nil)
 	exerciseTestableEventClock(t, fec, time.Second)
 }
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 768094a6677..f41da6b80ca 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -1548,7 +1548,7 @@ k8s.io/apiserver/pkg/util/flowcontrol
 k8s.io/apiserver/pkg/util/flowcontrol/counter
 k8s.io/apiserver/pkg/util/flowcontrol/debug
 k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing
-k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/clock
+k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/eventclock
 k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/promise
 k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/queueset
 k8s.io/apiserver/pkg/util/flowcontrol/fairqueuing/testing