src/profiler/cpu-profiler.cc

// 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 "src/profiler/cpu-profiler.h"

#include "src/debug/debug.h"
#include "src/deoptimizer.h"
#include "src/frames-inl.h"
#include "src/locked-queue-inl.h"
#include "src/log-inl.h"
#include "src/profiler/cpu-profiler-inl.h"
#include "src/vm-state-inl.h"

#include "include/v8-profiler.h"

namespace v8 {
namespace internal {

static const int kProfilerStackSize = 64 * KB;


ProfilerEventsProcessor::ProfilerEventsProcessor(ProfileGenerator* generator,
                                                 sampler::Sampler* sampler,
                                                 base::TimeDelta period)
    : Thread(Thread::Options("v8:ProfEvntProc", kProfilerStackSize)),
      generator_(generator),
      sampler_(sampler),
      running_(1),
      period_(period),
      last_code_event_id_(0),
      last_processed_code_event_id_(0) {}


ProfilerEventsProcessor::~ProfilerEventsProcessor() {}


void ProfilerEventsProcessor::Enqueue(const CodeEventsContainer& event) {
  event.generic.order = last_code_event_id_.Increment(1);
  events_buffer_.Enqueue(event);
}


void ProfilerEventsProcessor::AddDeoptStack(Isolate* isolate, Address from,
                                            int fp_to_sp_delta) {
  TickSampleEventRecord record(last_code_event_id_.Value());
  RegisterState regs;
  Address fp = isolate->c_entry_fp(isolate->thread_local_top());
  regs.sp = fp - fp_to_sp_delta;
  regs.fp = fp;
  regs.pc = from;
  record.sample.Init(isolate, regs, TickSample::kSkipCEntryFrame, false);
  ticks_from_vm_buffer_.Enqueue(record);
}

void ProfilerEventsProcessor::AddCurrentStack(Isolate* isolate,
                                              bool update_stats) {
  TickSampleEventRecord record(last_code_event_id_.Value());
  RegisterState regs;
  StackFrameIterator it(isolate);
  if (!it.done()) {
    StackFrame* frame = it.frame();
    regs.sp = frame->sp();
    regs.fp = frame->fp();
    regs.pc = frame->pc();
  }
  record.sample.Init(isolate, regs, TickSample::kSkipCEntryFrame, update_stats);
  ticks_from_vm_buffer_.Enqueue(record);
}


void ProfilerEventsProcessor::StopSynchronously() {
  if (!base::NoBarrier_AtomicExchange(&running_, 0)) return;
  Join();
}


bool ProfilerEventsProcessor::ProcessCodeEvent() {
  CodeEventsContainer record;
  if (events_buffer_.Dequeue(&record)) {
    switch (record.generic.type) {
#define PROFILER_TYPE_CASE(type, clss)                          \
      case CodeEventRecord::type:                               \
        record.clss##_.UpdateCodeMap(generator_->code_map());   \
        break;

      CODE_EVENTS_TYPE_LIST(PROFILER_TYPE_CASE)

#undef PROFILER_TYPE_CASE
      default: return true;  // Skip record.
    }
    last_processed_code_event_id_ = record.generic.order;
    return true;
  }
  return false;
}

ProfilerEventsProcessor::SampleProcessingResult
    ProfilerEventsProcessor::ProcessOneSample() {
  TickSampleEventRecord record1;
  if (ticks_from_vm_buffer_.Peek(&record1) &&
      (record1.order == last_processed_code_event_id_)) {
    TickSampleEventRecord record;
    ticks_from_vm_buffer_.Dequeue(&record);
    generator_->RecordTickSample(record.sample);
    return OneSampleProcessed;
  }

  const TickSampleEventRecord* record = ticks_buffer_.Peek();
  if (record == NULL) {
    if (ticks_from_vm_buffer_.IsEmpty()) return NoSamplesInQueue;
    return FoundSampleForNextCodeEvent;
  }
  if (record->order != last_processed_code_event_id_) {
    return FoundSampleForNextCodeEvent;
  }
  generator_->RecordTickSample(record->sample);
  ticks_buffer_.Remove();
  return OneSampleProcessed;
}


void ProfilerEventsProcessor::Run() {
  while (!!base::NoBarrier_Load(&running_)) {
    base::TimeTicks nextSampleTime =
        base::TimeTicks::HighResolutionNow() + period_;
    base::TimeTicks now;
    SampleProcessingResult result;
    // Keep processing existing events until we need to do next sample
    // or the ticks buffer is empty.
    do {
      result = ProcessOneSample();
      if (result == FoundSampleForNextCodeEvent) {
        // All ticks of the current last_processed_code_event_id_ are
        // processed, proceed to the next code event.
        ProcessCodeEvent();
      }
      now = base::TimeTicks::HighResolutionNow();
    } while (result != NoSamplesInQueue && now < nextSampleTime);

    if (nextSampleTime > now) {
#if V8_OS_WIN
      // Do not use Sleep on Windows as it is very imprecise.
      // Could be up to 16ms jitter, which is unacceptable for the purpose.
      while (base::TimeTicks::HighResolutionNow() < nextSampleTime) {
      }
#else
      base::OS::Sleep(nextSampleTime - now);
#endif
    }

    // Schedule next sample. sampler_ is NULL in tests.
    if (sampler_) sampler_->DoSample();
  }

  // Process remaining tick events.
  do {
    SampleProcessingResult result;
    do {
      result = ProcessOneSample();
    } while (result == OneSampleProcessed);
  } while (ProcessCodeEvent());
}


void* ProfilerEventsProcessor::operator new(size_t size) {
  return AlignedAlloc(size, V8_ALIGNOF(ProfilerEventsProcessor));
}


void ProfilerEventsProcessor::operator delete(void* ptr) {
  AlignedFree(ptr);
}


int CpuProfiler::GetProfilesCount() {
  // The count of profiles doesn't depend on a security token.
  return profiles_->profiles()->length();
}


CpuProfile* CpuProfiler::GetProfile(int index) {
  return profiles_->profiles()->at(index);
}


void CpuProfiler::DeleteAllProfiles() {
  if (is_profiling_) StopProcessor();
  ResetProfiles();
}


void CpuProfiler::DeleteProfile(CpuProfile* profile) {
  profiles_->RemoveProfile(profile);
  delete profile;
  if (profiles_->profiles()->is_empty() && !is_profiling_) {
    // If this was the last profile, clean up all accessory data as well.
    ResetProfiles();
  }
}

void CpuProfiler::CodeEventHandler(const CodeEventsContainer& evt_rec) {
  switch (evt_rec.generic.type) {
    case CodeEventRecord::CODE_CREATION:
    case CodeEventRecord::CODE_MOVE:
    case CodeEventRecord::CODE_DISABLE_OPT:
      processor_->Enqueue(evt_rec);
      break;
    case CodeEventRecord::CODE_DEOPT: {
      const CodeDeoptEventRecord* rec = &evt_rec.CodeDeoptEventRecord_;
      Address pc = reinterpret_cast<Address>(rec->pc);
      int fp_to_sp_delta = rec->fp_to_sp_delta;
      processor_->Enqueue(evt_rec);
      processor_->AddDeoptStack(isolate_, pc, fp_to_sp_delta);
      break;
    }
    default:
      UNREACHABLE();
  }
}

CpuProfiler::CpuProfiler(Isolate* isolate)
    : isolate_(isolate),
      sampling_interval_(base::TimeDelta::FromMicroseconds(
          FLAG_cpu_profiler_sampling_interval)),
      profiles_(new CpuProfilesCollection(isolate)),
      is_profiling_(false) {
  profiles_->set_cpu_profiler(this);
}

CpuProfiler::CpuProfiler(Isolate* isolate, CpuProfilesCollection* test_profiles,
                         ProfileGenerator* test_generator,
                         ProfilerEventsProcessor* test_processor)
    : isolate_(isolate),
      sampling_interval_(base::TimeDelta::FromMicroseconds(
          FLAG_cpu_profiler_sampling_interval)),
      profiles_(test_profiles),
      generator_(test_generator),
      processor_(test_processor),
      is_profiling_(false) {
  profiles_->set_cpu_profiler(this);
}

CpuProfiler::~CpuProfiler() {
  DCHECK(!is_profiling_);
}

void CpuProfiler::set_sampling_interval(base::TimeDelta value) {
  DCHECK(!is_profiling_);
  sampling_interval_ = value;
}

void CpuProfiler::ResetProfiles() {
  profiles_.reset(new CpuProfilesCollection(isolate_));
  profiles_->set_cpu_profiler(this);
}

void CpuProfiler::CollectSample() {
  if (processor_) {
    processor_->AddCurrentStack(isolate_);
  }
}

void CpuProfiler::StartProfiling(const char* title, bool record_samples) {
  if (profiles_->StartProfiling(title, record_samples)) {
    StartProcessorIfNotStarted();
  }
}


void CpuProfiler::StartProfiling(String* title, bool record_samples) {
  StartProfiling(profiles_->GetName(title), record_samples);
  isolate_->debug()->feature_tracker()->Track(DebugFeatureTracker::kProfiler);
}


void CpuProfiler::StartProcessorIfNotStarted() {
  if (processor_) {
    processor_->AddCurrentStack(isolate_);
    return;
  }
  Logger* logger = isolate_->logger();
  // Disable logging when using the new implementation.
  saved_is_logging_ = logger->is_logging_;
  logger->is_logging_ = false;
  sampler::Sampler* sampler = logger->sampler();
  generator_.reset(new ProfileGenerator(profiles_.get()));
  processor_.reset(new ProfilerEventsProcessor(generator_.get(), sampler,
                                               sampling_interval_));
  logger->SetUpProfilerListener();
  ProfilerListener* profiler_listener = logger->profiler_listener();
  profiler_listener->AddObserver(this);
  is_profiling_ = true;
  isolate_->set_is_profiling(true);
  // Enumerate stuff we already have in the heap.
  DCHECK(isolate_->heap()->HasBeenSetUp());
  if (!FLAG_prof_browser_mode) {
    logger->LogCodeObjects();
  }
  logger->LogCompiledFunctions();
  logger->LogAccessorCallbacks();
  LogBuiltins();
  // Enable stack sampling.
  sampler->SetHasProcessingThread(true);
  sampler->IncreaseProfilingDepth();
  processor_->AddCurrentStack(isolate_);
  processor_->StartSynchronously();
}


CpuProfile* CpuProfiler::StopProfiling(const char* title) {
  if (!is_profiling_) return nullptr;
  StopProcessorIfLastProfile(title);
  CpuProfile* result = profiles_->StopProfiling(title);
  if (result) {
    result->Print();
  }
  return result;
}


CpuProfile* CpuProfiler::StopProfiling(String* title) {
  if (!is_profiling_) return nullptr;
  const char* profile_title = profiles_->GetName(title);
  StopProcessorIfLastProfile(profile_title);
  return profiles_->StopProfiling(profile_title);
}


void CpuProfiler::StopProcessorIfLastProfile(const char* title) {
  if (profiles_->IsLastProfile(title)) {
    StopProcessor();
  }
}


void CpuProfiler::StopProcessor() {
  Logger* logger = isolate_->logger();
  sampler::Sampler* sampler =
      reinterpret_cast<sampler::Sampler*>(logger->ticker_);
  is_profiling_ = false;
  isolate_->set_is_profiling(false);
  ProfilerListener* profiler_listener = logger->profiler_listener();
  profiler_listener->RemoveObserver(this);
  processor_->StopSynchronously();
  logger->TearDownProfilerListener();
  processor_.reset();
  generator_.reset();
  sampler->SetHasProcessingThread(false);
  sampler->DecreaseProfilingDepth();
  logger->is_logging_ = saved_is_logging_;
}


void CpuProfiler::LogBuiltins() {
  Builtins* builtins = isolate_->builtins();
  DCHECK(builtins->is_initialized());
  for (int i = 0; i < Builtins::builtin_count; i++) {
    CodeEventsContainer evt_rec(CodeEventRecord::REPORT_BUILTIN);
    ReportBuiltinEventRecord* rec = &evt_rec.ReportBuiltinEventRecord_;
    Builtins::Name id = static_cast<Builtins::Name>(i);
    rec->start = builtins->builtin(id)->address();
    rec->builtin_id = id;
    processor_->Enqueue(evt_rec);
  }
}

}  // namespace internal
}  // namespace v8