1 files changed, 348 insertions, 0 deletions
diff --git a/dom/base/test/gtest/TestScheduler.cpp b/dom/base/test/gtest/TestScheduler.cpp
new file mode 100644
index 0000000000..00c578e556
--- /dev/null
+++ b/dom/base/test/gtest/TestScheduler.cpp
@@ -0,0 +1,348 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+#include "mozilla/dom/CCGCScheduler.h"
+#include "mozilla/TimeStamp.h"
+
+// This is a test for mozilla::CCGCScheduler.
+
+using namespace mozilla;
+
+static TimeDuration kOneSecond = TimeDuration::FromSeconds(1);
+static TimeDuration kTenthSecond = TimeDuration::FromSeconds(0.1);
+static TimeDuration kFrameDuration = TimeDuration::FromSeconds(1.0 / 60.0);
+
+static mozilla::TimeStamp sNow = TimeStamp::Now();
+
+static mozilla::TimeStamp AdvanceTime(TimeDuration aDuration) {
+  sNow += aDuration;
+  return sNow;
+}
+
+static TimeStamp Now() { return sNow; }
+
+static uint32_t sSuspected = 0;
+
+static uint32_t SuspectedCCObjects() { return sSuspected; }
+static void SetNumSuspected(uint32_t n) { sSuspected = n; }
+static void SuspectMore(uint32_t n) { sSuspected += n; }
+
+using CCRunnerState = mozilla::CCGCScheduler::CCRunnerState;
+
+class TestGC {
+ protected:
+  CCGCScheduler& mScheduler;
+
+ public:
+  explicit TestGC(CCGCScheduler& aScheduler) : mScheduler(aScheduler) {}
+  void Run(int aNumSlices);
+};
+
+void TestGC::Run(int aNumSlices) {
+  // Make the purple buffer nearly empty so it is itself not an adequate reason
+  // for wanting a CC.
+  static_assert(3 < mozilla::kCCPurpleLimit);
+  SetNumSuspected(3);
+
+  // Running the GC should not influence whether a CC is currently seen as
+  // needed. But the first time we run GC, it will be false; later, we will
+  // have run a GC and set it to true.
+  CCReason neededCCAtStartOfGC =
+      mScheduler.IsCCNeeded(Now(), SuspectedCCObjects());
+
+  mScheduler.NoteGCBegin(JS::GCReason::API);
+
+  for (int slice = 0; slice < aNumSlices; slice++) {
+    EXPECT_TRUE(mScheduler.InIncrementalGC());
+    TimeStamp idleDeadline = Now() + kTenthSecond;
+    js::SliceBudget budget =
+        mScheduler.ComputeInterSliceGCBudget(idleDeadline, Now());
+    TimeDuration budgetDuration =
+        TimeDuration::FromMilliseconds(budget.timeBudget());
+    EXPECT_NEAR(budgetDuration.ToSeconds(), 0.1, 1.e-6);
+    // Pretend the GC took exactly the budget.
+    AdvanceTime(budgetDuration);
+
+    EXPECT_EQ(mScheduler.IsCCNeeded(Now(), SuspectedCCObjects()),
+              neededCCAtStartOfGC);
+
+    // Mutator runs for 1 second.
+    AdvanceTime(kOneSecond);
+  }
+
+  mScheduler.NoteGCEnd();
+  mScheduler.SetNeedsFullGC(false);
+}
+
+class TestCC {
+ protected:
+  CCGCScheduler& mScheduler;
+
+ public:
+  explicit TestCC(CCGCScheduler& aScheduler) : mScheduler(aScheduler) {}
+
+  void Run(int aNumSlices) {
+    Prepare();
+    MaybePokeCC();
+    TimerFires(aNumSlices);
+    EndCycleCollectionCallback();
+    KillCCRunner();
+  }
+
+  virtual void Prepare() = 0;
+  virtual void MaybePokeCC();
+  virtual void TimerFires(int aNumSlices);
+  virtual void RunSlices(int aNumSlices);
+  virtual void RunSlice(TimeStamp aCCStartTime, TimeStamp aPrevSliceEnd,
+                        int aSliceNum, int aNumSlices) = 0;
+  virtual void ForgetSkippable();
+  virtual void EndCycleCollectionCallback();
+  virtual void KillCCRunner();
+};
+
+void TestCC::MaybePokeCC() {
+  // nsJSContext::MaybePokeCC
+
+  // In all tests so far, we will be running this just after a GC.
+  CCReason reason = mScheduler.ShouldScheduleCC(Now(), SuspectedCCObjects());
+  EXPECT_EQ(reason, CCReason::GC_FINISHED);
+
+  mScheduler.InitCCRunnerStateMachine(CCRunnerState::ReducePurple, reason);
+  EXPECT_TRUE(mScheduler.IsEarlyForgetSkippable());
+}
+
+void TestCC::TimerFires(int aNumSlices) {
+  // Series of CCRunner timer fires.
+  CCRunnerStep step;
+
+  while (true) {
+    SuspectMore(1000);
+    TimeStamp idleDeadline = Now() + kOneSecond;
+    step =
+        mScheduler.AdvanceCCRunner(idleDeadline, Now(), SuspectedCCObjects());
+    // Should first see a series of ForgetSkippable actions.
+    if (step.mAction != CCRunnerAction::ForgetSkippable ||
+        step.mParam.mRemoveChildless != KeepChildless) {
+      break;
+    }
+    EXPECT_EQ(step.mYield, Yield);
+    ForgetSkippable();
+  }
+
+  while (step.mYield == Continue) {
+    TimeStamp idleDeadline = Now() + kOneSecond;
+    step =
+        mScheduler.AdvanceCCRunner(idleDeadline, Now(), SuspectedCCObjects());
+  }
+  EXPECT_EQ(step.mAction, CCRunnerAction::ForgetSkippable);
+  EXPECT_EQ(step.mParam.mRemoveChildless, RemoveChildless);
+  ForgetSkippable();
+
+  TimeStamp idleDeadline = Now() + kOneSecond;
+  step = mScheduler.AdvanceCCRunner(idleDeadline, Now(), SuspectedCCObjects());
+  EXPECT_EQ(step.mAction, CCRunnerAction::CleanupContentUnbinder);
+  step = mScheduler.AdvanceCCRunner(idleDeadline, Now(), SuspectedCCObjects());
+  EXPECT_EQ(step.mAction, CCRunnerAction::CleanupDeferred);
+
+  mScheduler.NoteCCBegin(CCReason::API, Now(), 0, sSuspected, 0);
+  RunSlices(aNumSlices);
+}
+
+void TestCC::ForgetSkippable() {
+  uint32_t suspectedBefore = sSuspected;
+  // ...ForgetSkippable would happen here...
+  js::SliceBudget budget =
+      mScheduler.ComputeForgetSkippableBudget(Now(), Now() + kTenthSecond);
+  EXPECT_NEAR(budget.timeBudget(), kTenthSecond.ToMilliseconds(), 1);
+  AdvanceTime(kTenthSecond);
+  mScheduler.NoteForgetSkippableComplete(Now(), suspectedBefore,
+                                         SuspectedCCObjects());
+}
+
+void TestCC::RunSlices(int aNumSlices) {
+  TimeStamp ccStartTime = Now();
+  TimeStamp prevSliceEnd = ccStartTime;
+  for (int ccslice = 0; ccslice < aNumSlices; ccslice++) {
+    RunSlice(ccStartTime, prevSliceEnd, ccslice, aNumSlices);
+    prevSliceEnd = Now();
+  }
+
+  SetNumSuspected(0);
+}
+
+void TestCC::EndCycleCollectionCallback() {
+  // nsJSContext::EndCycleCollectionCallback
+  CycleCollectorResults results;
+  results.mFreedGCed = 10;
+  results.mFreedJSZones = 2;
+  mScheduler.NoteCCEnd(results, Now(), TimeDuration());
+
+  // Because > 0 zones were freed.
+  EXPECT_TRUE(mScheduler.NeedsGCAfterCC());
+}
+
+void TestCC::KillCCRunner() {
+  // nsJSContext::KillCCRunner
+  mScheduler.KillCCRunner();
+}
+
+class TestIdleCC : public TestCC {
+ public:
+  explicit TestIdleCC(CCGCScheduler& aScheduler) : TestCC(aScheduler) {}
+
+  void Prepare() override;
+  void RunSlice(TimeStamp aCCStartTime, TimeStamp aPrevSliceEnd, int aSliceNum,
+                int aNumSlices) override;
+};
+
+void TestIdleCC::Prepare() { EXPECT_TRUE(!mScheduler.InIncrementalGC()); }
+
+void TestIdleCC::RunSlice(TimeStamp aCCStartTime, TimeStamp aPrevSliceEnd,
+                          int aSliceNum, int aNumSlices) {
+  CCRunnerStep step;
+  TimeStamp idleDeadline = Now() + kTenthSecond;
+
+  // The scheduler should request a CycleCollect slice.
+  step = mScheduler.AdvanceCCRunner(idleDeadline, Now(), SuspectedCCObjects());
+  EXPECT_EQ(step.mAction, CCRunnerAction::CycleCollect);
+
+  // nsJSContext::RunCycleCollectorSlice
+
+  EXPECT_FALSE(mScheduler.InIncrementalGC());
+  bool preferShorter;
+  js::SliceBudget budget = mScheduler.ComputeCCSliceBudget(
+      idleDeadline, aCCStartTime, aPrevSliceEnd, Now(), &preferShorter);
+  // The scheduler will set the budget to our deadline (0.1sec in the future).
+  EXPECT_NEAR(budget.timeBudget(), kTenthSecond.ToMilliseconds(), 1);
+  EXPECT_FALSE(preferShorter);
+
+  AdvanceTime(kTenthSecond);
+}
+
+class TestNonIdleCC : public TestCC {
+ public:
+  explicit TestNonIdleCC(CCGCScheduler& aScheduler) : TestCC(aScheduler) {}
+
+  void Prepare() override;
+  void RunSlice(TimeStamp aCCStartTime, TimeStamp aPrevSliceEnd, int aSliceNum,
+                int aNumSlices) override;
+};
+
+void TestNonIdleCC::Prepare() {
+  EXPECT_TRUE(!mScheduler.InIncrementalGC());
+
+  // Advance time by an hour to give time for a user event in the past.
+  AdvanceTime(TimeDuration::FromSeconds(3600));
+}
+
+void TestNonIdleCC::RunSlice(TimeStamp aCCStartTime, TimeStamp aPrevSliceEnd,
+                             int aSliceNum, int aNumSlices) {
+  CCRunnerStep step;
+  TimeStamp nullDeadline;
+
+  // The scheduler should tell us to run a slice of cycle collection.
+  step = mScheduler.AdvanceCCRunner(nullDeadline, Now(), SuspectedCCObjects());
+  EXPECT_EQ(step.mAction, CCRunnerAction::CycleCollect);
+
+  // nsJSContext::RunCycleCollectorSlice
+
+  EXPECT_FALSE(mScheduler.InIncrementalGC());
+
+  bool preferShorter;
+  js::SliceBudget budget = mScheduler.ComputeCCSliceBudget(
+      nullDeadline, aCCStartTime, aPrevSliceEnd, Now(), &preferShorter);
+  if (aSliceNum == 0) {
+    // First slice of the CC, so always use the baseBudget which is
+    // kICCSliceBudget (3ms) for a non-idle slice.
+    EXPECT_NEAR(budget.timeBudget(), kICCSliceBudget.ToMilliseconds(), 0.1);
+  } else if (aSliceNum == 1) {
+    // Second slice still uses the baseBudget, since not much time has passed
+    // so none of the lengthening mechanisms have kicked in yet.
+    EXPECT_NEAR(budget.timeBudget(), kICCSliceBudget.ToMilliseconds(), 0.1);
+  } else if (aSliceNum == 2) {
+    // We're not overrunning kMaxICCDuration, so we don't go unlimited.
+    EXPECT_FALSE(budget.isUnlimited());
+    // This slice is delayed by twice the allowed amount. Slice time should be
+    // doubled.
+    EXPECT_NEAR(budget.timeBudget(), kICCSliceBudget.ToMilliseconds() * 2, 0.1);
+  } else {
+    // We're not overrunning kMaxICCDuration, so we don't go unlimited.
+    EXPECT_FALSE(budget.isUnlimited());
+
+    // These slices are not delayed, but enough time has passed that the
+    // dominating factor is now the linear ramp up to max slice time at the
+    // halfway point to kMaxICCDuration.
+    EXPECT_TRUE(budget.timeBudget() > kICCSliceBudget.ToMilliseconds());
+    EXPECT_TRUE(budget.timeBudget() <=
+                MainThreadIdlePeriod::GetLongIdlePeriod());
+  }
+  EXPECT_TRUE(preferShorter);  // Non-idle prefers shorter slices
+
+  AdvanceTime(TimeDuration::FromMilliseconds(budget.timeBudget()));
+  if (aSliceNum == 1) {
+    // Delay the third slice (only).
+    AdvanceTime(kICCIntersliceDelay * 2);
+  }
+}
+
+// Do a GC then CC then GC.
+static bool BasicScenario(CCGCScheduler& aScheduler, TestGC* aTestGC,
+                          TestCC* aTestCC) {
+  // Run a 10-slice incremental GC.
+  aTestGC->Run(10);
+
+  // After a GC, the scheduler should decide to do a full CC regardless of the
+  // number of purple buffer entries.
+  SetNumSuspected(3);
+  EXPECT_EQ(aScheduler.IsCCNeeded(Now(), SuspectedCCObjects()),
+            CCReason::GC_FINISHED);
+
+  // Now we should want to CC.
+  EXPECT_EQ(aScheduler.ShouldScheduleCC(Now(), SuspectedCCObjects()),
+            CCReason::GC_FINISHED);
+
+  // Do a 5-slice CC.
+  aTestCC->Run(5);
+
+  // Not enough suspected objects to deserve a CC.
+  EXPECT_EQ(aScheduler.IsCCNeeded(Now(), SuspectedCCObjects()),
+            CCReason::NO_REASON);
+  EXPECT_EQ(aScheduler.ShouldScheduleCC(Now(), SuspectedCCObjects()),
+            CCReason::NO_REASON);
+  SetNumSuspected(10000);
+
+  // We shouldn't want to CC again yet, it's too soon.
+  EXPECT_EQ(aScheduler.ShouldScheduleCC(Now(), SuspectedCCObjects()),
+            CCReason::NO_REASON);
+  AdvanceTime(mozilla::kCCDelay);
+
+  // *Now* it's time for another CC.
+  EXPECT_EQ(aScheduler.ShouldScheduleCC(Now(), SuspectedCCObjects()),
+            CCReason::MANY_SUSPECTED);
+
+  // Run a 3-slice incremental GC.
+  EXPECT_TRUE(!aScheduler.InIncrementalGC());
+  aTestGC->Run(3);
+
+  return true;
+}
+
+static CCGCScheduler scheduler;
+static TestGC gc(scheduler);
+static TestIdleCC ccIdle(scheduler);
+static TestNonIdleCC ccNonIdle(scheduler);
+
+TEST(TestScheduler, Idle)
+{
+  // Cannot CC until we GC once.
+  EXPECT_EQ(scheduler.ShouldScheduleCC(Now(), SuspectedCCObjects()),
+            CCReason::NO_REASON);
+
+  EXPECT_TRUE(BasicScenario(scheduler, &gc, &ccIdle));
+}
+
+TEST(TestScheduler, NonIdle)
+{ EXPECT_TRUE(BasicScenario(scheduler, &gc, &ccNonIdle)); }