Bug 1365539 - Refactor GC statistics phase stack to use a vector r=sfink (18e55037) · Commits · The Tor Project / Applications / Mullvad Browser

js/src/builtin/TestingFunctions.cpp

+5 −1

Original line number	Diff line number	Diff line
		@@ -3737,7 +3737,11 @@ SetGCCallback(JSContext* cx, unsigned argc, Value* vp)
		if (!ToInt32(cx, v, &depth))
		return false;
		}
		if (depth > int32_t(gcstats::Statistics::MAX_NESTING - 4)) {
		if (depth < 0) {
		JS_ReportErrorASCII(cx, "Nesting depth cannot be negative");
		return false;
		}
		if (depth + gcstats::MAX_PHASE_NESTING > gcstats::Statistics::MAX_SUSPENDED_PHASES) {
		JS_ReportErrorASCII(cx, "Nesting depth too large, would overflow");
		return false;
		}

js/src/gc/GenerateStatsPhases.py

+10 −0

Original line number	Diff line number	Diff line
		@@ -231,6 +231,10 @@ for phaseKind in AllPhaseKinds:
		for index, phase in enumerate(phases):
		phase.name = "%s_%d" % (phaseKind.name, index + 1)

		# Find the maximum phase nesting.

		MaxPhaseNesting = max(phase.depth for phase in AllPhases) + 1

		# Generate code.

		def writeList(out, items):
		@@ -267,6 +271,12 @@ def generateHeader(out):
		"IMPLICIT_SUSPENSION"
		]
		writeEnumClass(out, "Phase", "uint8_t", phaseNames, extraPhases)
		out.write("\n")

		#
		# Generate MAX_PHASE_NESTING constant.
		#
		out.write("static const size_t MAX_PHASE_NESTING = %d;\n" % MaxPhaseNesting)

		def generateCpp(out):
		#

js/src/gc/Statistics.cpp

+32 −38

Original line number	Diff line number	Diff line
		@@ -124,10 +124,10 @@ t(TimeDuration duration)
		return duration.ToMilliseconds();
		}

		Phase
		inline Phase
		Statistics::currentPhase() const
		{
		return phaseNestingDepth ? phaseNesting[phaseNestingDepth - 1] : Phase::NONE;
		return phaseStack.empty() ? Phase::NONE : phaseStack.back();
		}

		PhaseKind
		@@ -137,7 +137,7 @@ Statistics::currentPhaseKind() const
		// PhaseKind::MUTATOR phase.

		Phase phase = currentPhase();
		MOZ_ASSERT_IF(phase == Phase::MUTATOR, phaseNestingDepth == 1);
		MOZ_ASSERT_IF(phase == Phase::MUTATOR, phaseStack.length() == 1);
		if (phase == Phase::NONE \|\| phase == Phase::MUTATOR)
		return PhaseKind::NONE;

		@@ -638,8 +638,6 @@ Statistics::Statistics(JSRuntime* rt)
		nonincrementalReason_(gc::AbortReason::None),
		preBytes(0),
		maxPauseInInterval(0),
		phaseNestingDepth(0),
		suspended(0),
		sliceCallback(nullptr),
		nurseryCollectionCallback(nullptr),
		aborted(false),
		@@ -648,6 +646,10 @@ Statistics::Statistics(JSRuntime* rt)
		{
		for (auto& count : counts)
		count = 0;
		PodZero(&totalTimes_);

		MOZ_ALWAYS_TRUE(phaseStack.reserve(MAX_PHASE_NESTING));
		MOZ_ALWAYS_TRUE(suspendedPhases.reserve(MAX_SUSPENDED_PHASES));

		const char* env = getenv("MOZ_GCTIMER");
		if (env) {
		@@ -674,8 +676,6 @@ Statistics::Statistics(JSRuntime* rt)
		enableProfiling_ = true;
		profileThreshold_ = TimeDuration::FromMilliseconds(atoi(env));
		}

		PodZero(&totalTimes_);
		}

		Statistics::~Statistics()
		@@ -1030,14 +1030,14 @@ Statistics::reportLongestPhase(const PhaseTimeTable& times, int telemetryId)
		bool
		Statistics::startTimingMutator()
		{
		if (phaseNestingDepth != 0) {
		if (phaseStack.length() != 0) {
		// Should only be called from outside of GC.
		MOZ_ASSERT(phaseNestingDepth == 1);
		MOZ_ASSERT(phaseNesting[0] == Phase::MUTATOR);
		MOZ_ASSERT(phaseStack.length() == 1);
		MOZ_ASSERT(phaseStack[0] == Phase::MUTATOR);
		return false;
		}

		MOZ_ASSERT(suspended == 0);
		MOZ_ASSERT(suspendedPhases.empty());

		timedGCTime = 0;
		phaseStartTimes[Phase::MUTATOR] = TimeStamp();
		@@ -1052,7 +1052,7 @@ bool
		Statistics::stopTimingMutator(double& mutator_ms, double& gc_ms)
		{
		// This should only be called from outside of GC, while timing the mutator.
		if (phaseNestingDepth != 1 \|\| phaseNesting[0] != Phase::MUTATOR)
		if (phaseStack.length() != 1 \|\| phaseStack[0] != Phase::MUTATOR)
		return false;

		endPhase(PhaseKind::MUTATOR);
		@@ -1067,30 +1067,27 @@ Statistics::suspendPhases(PhaseKind suspension)
		{
		MOZ_ASSERT(suspension == PhaseKind::EXPLICIT_SUSPENSION \|\|
		suspension == PhaseKind::IMPLICIT_SUSPENSION);
		while (phaseNestingDepth) {
		MOZ_ASSERT(suspended < mozilla::ArrayLength(suspendedPhases));
		Phase parent = phaseNesting[phaseNestingDepth - 1];
		suspendedPhases[suspended++] = parent;
		while (!phaseStack.empty()) {
		MOZ_ASSERT(suspendedPhases.length() < MAX_SUSPENDED_PHASES);
		Phase parent = phaseStack.back();
		suspendedPhases.infallibleAppend(parent);
		recordPhaseEnd(parent);
		}
		suspendedPhases[suspended++] = lookupChildPhase(suspension);
		suspendedPhases.infallibleAppend(lookupChildPhase(suspension));
		}

		void
		Statistics::resumePhases()
		{
		suspended--;
		#ifdef DEBUG
		Phase popped = suspendedPhases[suspended];
		MOZ_ASSERT(popped == Phase::EXPLICIT_SUSPENSION \|\|
		popped == Phase::IMPLICIT_SUSPENSION);
		#endif
		MOZ_ASSERT(suspendedPhases.back() == Phase::EXPLICIT_SUSPENSION \|\|
		suspendedPhases.back() == Phase::IMPLICIT_SUSPENSION);
		suspendedPhases.popBack();

		while (suspended &&
		suspendedPhases[suspended - 1] != Phase::EXPLICIT_SUSPENSION &&
		suspendedPhases[suspended - 1] != Phase::IMPLICIT_SUSPENSION)
		while (!suspendedPhases.empty() &&
		suspendedPhases.back() != Phase::EXPLICIT_SUSPENSION &&
		suspendedPhases.back() != Phase::IMPLICIT_SUSPENSION)
		{
		Phase resumePhase = suspendedPhases[--suspended];
		Phase resumePhase = suspendedPhases.popCopy();
		if (resumePhase == Phase::MUTATOR)
		timedGCTime += TimeStamp::Now() - timedGCStart;
		recordPhaseBegin(resumePhase);
		@@ -1104,9 +1101,8 @@ Statistics::beginPhase(PhaseKind phaseKind)
		MOZ_ASSERT(phaseKind != PhaseKind::GC_BEGIN && phaseKind != PhaseKind::GC_END);

		// PhaseKind::MUTATOR is suspended while performing GC.
		if (currentPhase() == Phase::MUTATOR) {
		if (currentPhase() == Phase::MUTATOR)
		suspendPhases(PhaseKind::IMPLICIT_SUSPENSION);
		}

		recordPhaseBegin(lookupChildPhase(phaseKind));
		}
		@@ -1117,12 +1113,10 @@ Statistics::recordPhaseBegin(Phase phase)
		// Guard against any other re-entry.
		MOZ_ASSERT(!phaseStartTimes[phase]);

		MOZ_ASSERT(phaseNestingDepth < MAX_NESTING);
		MOZ_ASSERT(phaseStack.length() < MAX_PHASE_NESTING);
		MOZ_ASSERT(phases[phase].parent == currentPhase());

		phaseNesting[phaseNestingDepth] = phase;
		phaseNestingDepth++;

		phaseStack.infallibleAppend(phase);
		phaseStartTimes[phase] = TimeStamp::Now();
		}

		@@ -1134,7 +1128,7 @@ Statistics::recordPhaseEnd(Phase phase)
		if (phase == Phase::MUTATOR)
		timedGCStart = now;

		phaseNestingDepth--;
		phaseStack.popBack();

		TimeDuration t = now - phaseStartTimes[phase];
		if (!slices_.empty())
		@@ -1154,9 +1148,9 @@ Statistics::endPhase(PhaseKind phaseKind)

		// When emptying the stack, we may need to return to timing the mutator
		// (PhaseKind::MUTATOR).
		if (phaseNestingDepth == 0 &&
		suspended > 0 &&
		suspendedPhases[suspended - 1] == Phase::IMPLICIT_SUSPENSION)
		if (phaseStack.empty() &&
		!suspendedPhases.empty() &&
		suspendedPhases.back() == Phase::IMPLICIT_SUSPENSION)
		{
		resumePhases();
		}
		@@ -1182,7 +1176,7 @@ void
		Statistics::endParallelPhase(PhaseKind phaseKind, const GCParallelTask* task)
		{
		Phase phase = lookupChildPhase(phaseKind);
		phaseNestingDepth--;
		phaseStack.popBack();

		if (!slices_.empty())
		slices_.back().phaseTimes[phase] += task->duration();

js/src/gc/Statistics.h

+3 −5

Original line number	Diff line number	Diff line
		@@ -206,7 +206,7 @@ struct Statistics

		PhaseKind currentPhaseKind() const;

		static const size_t MAX_NESTING = 20;
		static const size_t MAX_SUSPENDED_PHASES = MAX_PHASE_NESTING * 3;

		struct SliceData {
		SliceData(SliceBudget budget, JS::gcreason::Reason reason,
		@@ -304,8 +304,7 @@ struct Statistics
		mutable TimeDuration maxPauseInInterval;

		/* Phases that are currently on stack. */
		Array<Phase, MAX_NESTING> phaseNesting;
		size_t phaseNestingDepth;
		Vector<Phase, MAX_PHASE_NESTING, SystemAllocPolicy> phaseStack;

		/*
		* Certain phases can interrupt the phase stack, eg callback phases. When
		@@ -314,8 +313,7 @@ struct Statistics
		* suspensions by suspending multiple stacks with a PhaseKind::SUSPENSION in
		* between).
		*/
		Array<Phase, MAX_NESTING * 3> suspendedPhases;
		size_t suspended;
		Vector<Phase, MAX_SUSPENDED_PHASES, SystemAllocPolicy> suspendedPhases;

		/* Sweep times for SCCs of compartments. */
		Vector<TimeDuration, 0, SystemAllocPolicy> sccTimes;

js/src/tests/shell/gcstats.js

+1 −1

Original line number	Diff line number	Diff line
		@@ -31,7 +31,7 @@ garbage();

		setGCCallback({
		action: "majorGC",
		depth: 10,
		depth: 8,
		phases: "begin"
		});