blob: e7ca3fbd7b23b97ae747893894903591be37c003 [file] [log] [blame]
// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <atomic>
#include <memory>
#include "src/base/platform/condition-variable.h"
#include "src/base/platform/mutex.h"
#include "src/base/platform/time.h"
#include "src/profiler/circular-queue.h"
#include "src/profiler/profiler-listener.h"
#include "src/profiler/tick-sample.h"
#include "src/utils/locked-queue.h"
namespace v8 {
namespace sampler {
class Sampler;
} // namespace sampler
namespace internal {
// Forward declarations.
class CodeEntry;
class CodeMap;
class CpuProfilesCollection;
class Isolate;
class Symbolizer;
V(CODE_CREATION, CodeCreateEventRecord) \
V(CODE_MOVE, CodeMoveEventRecord) \
V(CODE_DISABLE_OPT, CodeDisableOptEventRecord) \
V(CODE_DEOPT, CodeDeoptEventRecord) \
V(REPORT_BUILTIN, ReportBuiltinEventRecord)
class CodeEventRecord {
#define DECLARE_TYPE(type, ignore) type,
Type type;
mutable unsigned order;
class CodeCreateEventRecord : public CodeEventRecord {
Address instruction_start;
CodeEntry* entry;
unsigned instruction_size;
V8_INLINE void UpdateCodeMap(CodeMap* code_map);
class CodeMoveEventRecord : public CodeEventRecord {
Address from_instruction_start;
Address to_instruction_start;
V8_INLINE void UpdateCodeMap(CodeMap* code_map);
class CodeDisableOptEventRecord : public CodeEventRecord {
Address instruction_start;
const char* bailout_reason;
V8_INLINE void UpdateCodeMap(CodeMap* code_map);
class CodeDeoptEventRecord : public CodeEventRecord {
Address instruction_start;
const char* deopt_reason;
int deopt_id;
Address pc;
int fp_to_sp_delta;
CpuProfileDeoptFrame* deopt_frames;
int deopt_frame_count;
V8_INLINE void UpdateCodeMap(CodeMap* code_map);
class ReportBuiltinEventRecord : public CodeEventRecord {
Address instruction_start;
unsigned instruction_size;
Builtins::Name builtin_id;
V8_INLINE void UpdateCodeMap(CodeMap* code_map);
// A record type for sending samples from the main thread/signal handler to the
// profiling thread.
class TickSampleEventRecord {
// The parameterless constructor is used when we dequeue data from
// the ticks buffer.
TickSampleEventRecord() = default;
explicit TickSampleEventRecord(unsigned order) : order(order) { }
unsigned order;
TickSample sample;
// A record type for sending code events (e.g. create, move, delete) to the
// profiling thread.
class CodeEventsContainer {
explicit CodeEventsContainer(
CodeEventRecord::Type type = CodeEventRecord::NONE) {
generic.type = type;
union {
CodeEventRecord generic;
#define DECLARE_CLASS(ignore, type) type type##_;
// Maintains the number of active CPU profilers in an isolate, and routes
// logging to a given ProfilerListener.
class ProfilingScope {
ProfilingScope(Isolate* isolate, ProfilerListener* listener);
Isolate* const isolate_;
ProfilerListener* const listener_;
class ProfilerCodeObserver;
// This class implements both the profile events processor thread and
// methods called by event producers: VM and stack sampler threads.
class V8_EXPORT_PRIVATE ProfilerEventsProcessor : public base::Thread,
public CodeEventObserver {
~ProfilerEventsProcessor() override;
void CodeEventHandler(const CodeEventsContainer& evt_rec) override;
// Thread control.
void Run() override = 0;
void StopSynchronously();
bool running() { return running_.load(std::memory_order_relaxed); }
void Enqueue(const CodeEventsContainer& event);
// Puts current stack into the tick sample events buffer.
void AddCurrentStack(bool update_stats = false);
void AddDeoptStack(Address from, int fp_to_sp_delta);
// Add a sample into the tick sample events buffer. Used for testing.
void AddSample(TickSample sample);
virtual void SetSamplingInterval(base::TimeDelta) {}
ProfilerEventsProcessor(Isolate* isolate, Symbolizer* symbolizer,
ProfilerCodeObserver* code_observer);
// Called from events processing thread (Run() method.)
bool ProcessCodeEvent();
enum SampleProcessingResult {
virtual SampleProcessingResult ProcessOneSample() = 0;
Symbolizer* symbolizer_;
ProfilerCodeObserver* code_observer_;
std::atomic_bool running_{true};
base::ConditionVariable running_cond_;
base::Mutex running_mutex_;
LockedQueue<CodeEventsContainer> events_buffer_;
LockedQueue<TickSampleEventRecord> ticks_from_vm_buffer_;
std::atomic<unsigned> last_code_event_id_;
unsigned last_processed_code_event_id_;
Isolate* isolate_;
class V8_EXPORT_PRIVATE SamplingEventsProcessor
: public ProfilerEventsProcessor {
SamplingEventsProcessor(Isolate* isolate, Symbolizer* symbolizer,
ProfilerCodeObserver* code_observer,
CpuProfilesCollection* profiles,
base::TimeDelta period, bool use_precise_sampling);
~SamplingEventsProcessor() override;
// SamplingCircularQueue has stricter alignment requirements than a normal new
// can fulfil, so we need to provide our own new/delete here.
void* operator new(size_t size);
void operator delete(void* ptr);
void Run() override;
void SetSamplingInterval(base::TimeDelta period) override;
// Tick sample events are filled directly in the buffer of the circular
// queue (because the structure is of fixed width, but usually not all
// stack frame entries are filled.) This method returns a pointer to the
// next record of the buffer.
// These methods are not thread-safe and should only ever be called by one
// producer (from CpuSampler::SampleStack()). For testing, use AddSample.
inline TickSample* StartTickSample();
inline void FinishTickSample();
sampler::Sampler* sampler() { return sampler_.get(); }
base::TimeDelta period() const { return period_; }
SampleProcessingResult ProcessOneSample() override;
void SymbolizeAndAddToProfiles(const TickSampleEventRecord* record);
static const size_t kTickSampleBufferSize = 512 * KB;
static const size_t kTickSampleQueueLength =
kTickSampleBufferSize / sizeof(TickSampleEventRecord);
kTickSampleQueueLength> ticks_buffer_;
std::unique_ptr<sampler::Sampler> sampler_;
CpuProfilesCollection* profiles_;
base::TimeDelta period_; // Samples & code events processing period.
const bool use_precise_sampling_; // Whether or not busy-waiting is used for
// low sampling intervals on Windows.
// Builds and maintains a CodeMap tracking code objects on the VM heap. While
// alive, logs generated code, callbacks, and builtins from the isolate.
// Redirects events to the profiler events processor when present.
class V8_EXPORT_PRIVATE ProfilerCodeObserver : public CodeEventObserver {
explicit ProfilerCodeObserver(Isolate*);
void CodeEventHandler(const CodeEventsContainer& evt_rec) override;
CodeMap* code_map() { return &code_map_; }
void ClearCodeMap();
friend class ProfilerEventsProcessor;
void CodeEventHandlerInternal(const CodeEventsContainer& evt_rec);
void CreateEntriesForRuntimeCallStats();
void LogBuiltins();
ProfilerEventsProcessor* processor() { return processor_; }
// Redirects code events to be enqueued on the given events processor.
void set_processor(ProfilerEventsProcessor* processor) {
processor_ = processor;
// Stops redirection of code events onto an events processor.
void clear_processor() { processor_ = nullptr; }
Isolate* const isolate_;
CodeMap code_map_;
ProfilerEventsProcessor* processor_;
// The CpuProfiler is a sampling CPU profiler for JS frames. It corresponds to
// v8::CpuProfiler at the API level. It spawns an additional thread which is
// responsible for triggering samples and then symbolizing the samples with
// function names. To symbolize on a background thread, the profiler copies
// metadata about generated code off-heap.
// Sampling is done using posix signals (except on Windows). The profiling
// thread sends a signal to the main thread, based on a timer. The signal
// handler can interrupt the main thread between any abitrary instructions.
// This means we are very careful about reading stack values during the signal
// handler as we could be in the middle of an operation that is modifying the
// stack.
// The story on Windows is similar except we use thread suspend and resume.
// Samples are passed to the profiling thread via a circular buffer. The
// profiling thread symbolizes the samples by looking up the code pointers
// against its own list of code objects. The profiling thread also listens for
// code creation/move/deletion events (from the GC), to maintain its list of
// code objects accurately.
class V8_EXPORT_PRIVATE CpuProfiler {
explicit CpuProfiler(Isolate* isolate, CpuProfilingNamingMode = kDebugNaming,
CpuProfilingLoggingMode = kLazyLogging);
CpuProfiler(Isolate* isolate, CpuProfilingNamingMode naming_mode,
CpuProfilingLoggingMode logging_mode,
CpuProfilesCollection* profiles, Symbolizer* test_symbolizer,
ProfilerEventsProcessor* test_processor);
static void CollectSample(Isolate* isolate);
using ProfilingMode = v8::CpuProfilingMode;
using NamingMode = v8::CpuProfilingNamingMode;
using LoggingMode = v8::CpuProfilingLoggingMode;
using StartProfilingStatus = CpuProfilingStatus;
base::TimeDelta sampling_interval() const { return base_sampling_interval_; }
void set_sampling_interval(base::TimeDelta value);
void set_use_precise_sampling(bool);
void CollectSample();
StartProfilingStatus StartProfiling(const char* title,
CpuProfilingOptions options = {});
StartProfilingStatus StartProfiling(String title,
CpuProfilingOptions options = {});
CpuProfile* StopProfiling(const char* title);
CpuProfile* StopProfiling(String title);
int GetProfilesCount();
CpuProfile* GetProfile(int index);
void DeleteAllProfiles();
void DeleteProfile(CpuProfile* profile);
bool is_profiling() const { return is_profiling_; }
Symbolizer* symbolizer() const { return symbolizer_.get(); }
ProfilerEventsProcessor* processor() const { return processor_.get(); }
Isolate* isolate() const { return isolate_; }
ProfilerListener* profiler_listener_for_test() const {
return profiler_listener_.get();
CodeMap* code_map_for_test() { return code_observer_.code_map(); }
void StartProcessorIfNotStarted();
void StopProcessorIfLastProfile(const char* title);
void StopProcessor();
void ResetProfiles();
void EnableLogging();
void DisableLogging();
// Computes a sampling interval sufficient to accomodate attached profiles.
base::TimeDelta ComputeSamplingInterval() const;
// Dynamically updates the sampler to use a sampling interval sufficient for
// child profiles.
void AdjustSamplingInterval();
Isolate* const isolate_;
const NamingMode naming_mode_;
const LoggingMode logging_mode_;
bool use_precise_sampling_ = true;
// Sampling interval to which per-profile sampling intervals will be clamped
// to a multiple of, or used as the default if unspecified.
base::TimeDelta base_sampling_interval_;
std::unique_ptr<CpuProfilesCollection> profiles_;
std::unique_ptr<Symbolizer> symbolizer_;
std::unique_ptr<ProfilerEventsProcessor> processor_;
std::unique_ptr<ProfilerListener> profiler_listener_;
std::unique_ptr<ProfilingScope> profiling_scope_;
ProfilerCodeObserver code_observer_;
bool is_profiling_;
} // namespace internal
} // namespace v8