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/* -*- 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 */
#include "GeckoProfiler.h"
#include "ProfileBufferEntry.h"
#include "mozilla/Maybe.h"
#include "mozilla/PowerOfTwo.h"
#include "mozilla/ProfileBufferChunkManagerSingle.h"
#include "mozilla/ProfileChunkedBuffer.h"
class ProcessStreamingContext;
class RunningTimes;
// Class storing most profiling data in a ProfileChunkedBuffer.
// This class is used as a queue of entries which, after construction, never
// allocates. This makes it safe to use in the profiler's "critical section".
class ProfileBuffer final {
// ProfileBuffer constructor
// @param aBuffer The in-session ProfileChunkedBuffer to use as buffer
// manager.
explicit ProfileBuffer(mozilla::ProfileChunkedBuffer& aBuffer);
mozilla::ProfileChunkedBuffer& UnderlyingChunkedBuffer() const {
return mEntries;
bool IsThreadSafe() const { return mEntries.IsThreadSafe(); }
// Add |aEntry| to the buffer, ignoring what kind of entry it is.
uint64_t AddEntry(const ProfileBufferEntry& aEntry);
// Add to the buffer a sample start (ThreadId) entry for aThreadId.
// Returns the position of the entry.
uint64_t AddThreadIdEntry(ProfilerThreadId aThreadId);
void CollectCodeLocation(
const char* aLabel, const char* aStr, uint32_t aFrameFlags,
uint64_t aInnerWindowID, const mozilla::Maybe<uint32_t>& aLineNumber,
const mozilla::Maybe<uint32_t>& aColumnNumber,
const mozilla::Maybe<JS::ProfilingCategoryPair>& aCategoryPair);
// Maximum size of a frameKey string that we'll handle.
static const size_t kMaxFrameKeyLength = 512;
// Add JIT frame information to aJITFrameInfo for any JitReturnAddr entries
// that are currently in the buffer at or after aRangeStart, in samples
// for the given thread.
void AddJITInfoForRange(uint64_t aRangeStart, ProfilerThreadId aThreadId,
JSContext* aContext, JITFrameInfo& aJITFrameInfo,
mozilla::ProgressLogger aProgressLogger) const;
// Stream JSON for samples in the buffer to aWriter, using the supplied
// UniqueStacks object.
// Only streams samples for the given thread ID and which were taken at or
// after aSinceTime. If ID is 0, ignore the stored thread ID; this should only
// be used when the buffer contains only one sample.
// aUniqueStacks needs to contain information about any JIT frames that we
// might encounter in the buffer, before this method is called. In other
// words, you need to have called AddJITInfoForRange for every range that
// might contain JIT frame information before calling this method.
// Return the thread ID of the streamed sample(s), or 0.
ProfilerThreadId StreamSamplesToJSON(
SpliceableJSONWriter& aWriter, ProfilerThreadId aThreadId,
double aSinceTime, UniqueStacks& aUniqueStacks,
mozilla::ProgressLogger aProgressLogger) const;
void StreamMarkersToJSON(SpliceableJSONWriter& aWriter,
ProfilerThreadId aThreadId,
const mozilla::TimeStamp& aProcessStartTime,
double aSinceTime, UniqueStacks& aUniqueStacks,
mozilla::ProgressLogger aProgressLogger) const;
// Stream samples and markers from all threads that `aProcessStreamingContext`
// accepts.
void StreamSamplesAndMarkersToJSON(
ProcessStreamingContext& aProcessStreamingContext,
mozilla::ProgressLogger aProgressLogger) const;
void StreamPausedRangesToJSON(SpliceableJSONWriter& aWriter,
double aSinceTime,
mozilla::ProgressLogger aProgressLogger) const;
void StreamProfilerOverheadToJSON(
SpliceableJSONWriter& aWriter,
const mozilla::TimeStamp& aProcessStartTime, double aSinceTime,
mozilla::ProgressLogger aProgressLogger) const;
void StreamCountersToJSON(SpliceableJSONWriter& aWriter,
const mozilla::TimeStamp& aProcessStartTime,
double aSinceTime,
mozilla::ProgressLogger aProgressLogger) const;
// Find (via |aLastSample|) the most recent sample for the thread denoted by
// |aThreadId| and clone it, patching in the current time as appropriate.
// Mutate |aLastSample| to point to the newly inserted sample.
// Returns whether duplication was successful.
bool DuplicateLastSample(ProfilerThreadId aThreadId, double aSampleTimeMs,
mozilla::Maybe<uint64_t>& aLastSample,
const RunningTimes& aRunningTimes);
void DiscardSamplesBeforeTime(double aTime);
// Read an entry in the buffer.
ProfileBufferEntry GetEntry(uint64_t aPosition) const {
return mEntries.ReadAt(
[&](mozilla::Maybe<mozilla::ProfileBufferEntryReader>&& aMER) {
ProfileBufferEntry entry;
if (aMER.isSome()) {
if (aMER->CurrentBlockIndex().ConvertToProfileBufferIndex() ==
aPosition) {
// If we're here, it means `aPosition` pointed at a valid block.
MOZ_RELEASE_ASSERT(aMER->RemainingBytes() <= sizeof(entry));
aMER->ReadBytes(&entry, aMER->RemainingBytes());
} else {
// EntryReader at the wrong position, pretend to have read
// everything.
return entry;
size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
void CollectOverheadStats(double aSamplingTimeMs,
mozilla::TimeDuration aLocking,
mozilla::TimeDuration aCleaning,
mozilla::TimeDuration aCounters,
mozilla::TimeDuration aThreads);
ProfilerBufferInfo GetProfilerBufferInfo() const;
// Add |aEntry| to the provided ProfileChunkedBuffer.
// `static` because it may be used to add an entry to a `ProfileChunkedBuffer`
// that is not attached to a `ProfileBuffer`.
static mozilla::ProfileBufferBlockIndex AddEntry(
mozilla::ProfileChunkedBuffer& aProfileChunkedBuffer,
const ProfileBufferEntry& aEntry);
// Add a sample start (ThreadId) entry for aThreadId to the provided
// ProfileChunkedBuffer. Returns the position of the entry.
// `static` because it may be used to add an entry to a `ProfileChunkedBuffer`
// that is not attached to a `ProfileBuffer`.
static mozilla::ProfileBufferBlockIndex AddThreadIdEntry(
mozilla::ProfileChunkedBuffer& aProfileChunkedBuffer,
ProfilerThreadId aThreadId);
// The storage in which this ProfileBuffer stores its entries.
mozilla::ProfileChunkedBuffer& mEntries;
// `BufferRangeStart()` and `BufferRangeEnd()` return `uint64_t` values
// corresponding to the first entry and past the last entry stored in
// `mEntries`.
// The returned values are not guaranteed to be stable, because other threads
// may also be accessing the buffer concurrently. But they will always
// increase, and can therefore give an indication of how far these values have
// *at least* reached. In particular:
// - Entries whose index is strictly less that `BufferRangeStart()` have been
// discarded by now, so any related data may also be safely discarded.
// - It is safe to try and read entries at any index strictly less than
// `BufferRangeEnd()` -- but note that these reads may fail by the time you
// request them, as old entries get overwritten by new ones.
uint64_t BufferRangeStart() const { return mEntries.GetState().mRangeStart; }
uint64_t BufferRangeEnd() const { return mEntries.GetState().mRangeEnd; }
// Single pre-allocated chunk (to avoid spurious mallocs), used when:
// - Duplicating sleeping stacks (hence scExpectedMaximumStackSize).
// - Adding JIT info.
// - Streaming stacks to JSON.
// Mutable because it's accessed from non-multithreaded const methods.
mutable mozilla::Maybe<mozilla::ProfileBufferChunkManagerSingle>
mozilla::ProfileBufferChunkManagerSingle& WorkerChunkManager() const {
if (mMaybeWorkerChunkManager.isNothing()) {
// Only actually allocate it on first use. (Some ProfileBuffers are
// temporary and don't actually need this.)
mozilla::ProfileBufferChunk::SizeofChunkMetadata() +
return *mMaybeWorkerChunkManager;
// GetStreamingParametersForThreadCallback:
// (ProfilerThreadId) -> Maybe<StreamingParametersForThread>
template <typename GetStreamingParametersForThreadCallback>
ProfilerThreadId DoStreamSamplesAndMarkersToJSON(
mozilla::FailureLatch& aFailureLatch,
double aSinceTime, ProcessStreamingContext* aStreamingContextForMarkers,
mozilla::ProgressLogger aProgressLogger) const;
double mFirstSamplingTimeUs = 0.0;
double mLastSamplingTimeUs = 0.0;
ProfilerStats mIntervalsUs;
ProfilerStats mOverheadsUs;
ProfilerStats mLockingsUs;
ProfilerStats mCleaningsUs;
ProfilerStats mCountersUs;
ProfilerStats mThreadsUs;
* Helper type used to implement ProfilerStackCollector. This type is used as
* the collector for MergeStacks by ProfileBuffer. It holds a reference to the
* buffer, as well as additional feature flags which are needed to control the
* data collection strategy
class ProfileBufferCollector final : public ProfilerStackCollector {
ProfileBufferCollector(ProfileBuffer& aBuf, uint64_t aSamplePos,
uint64_t aBufferRangeStart)
: mBuf(aBuf),
mBufferRangeStart(aBufferRangeStart) {
mSamplePositionInBuffer >= mBufferRangeStart,
"The sample position should always be after the buffer range start");
// Position at which the sample starts in the profiler buffer (which may be
// different from the buffer in which the sample data is collected here).
mozilla::Maybe<uint64_t> SamplePositionInBuffer() override {
return mozilla::Some(mSamplePositionInBuffer);
// Profiler buffer's range start (which may be different from the buffer in
// which the sample data is collected here).
mozilla::Maybe<uint64_t> BufferRangeStart() override {
return mozilla::Some(mBufferRangeStart);
virtual void CollectNativeLeafAddr(void* aAddr) override;
virtual void CollectJitReturnAddr(void* aAddr) override;
virtual void CollectWasmFrame(JS::ProfilingCategoryPair aCategory,
const char* aLabel) override;
virtual void CollectProfilingStackFrame(
const js::ProfilingStackFrame& aFrame) override;
ProfileBuffer& mBuf;
uint64_t mSamplePositionInBuffer;
uint64_t mBufferRangeStart;