Version 3.20.11.1

src/profile-generator.h

Index: src/profile-generator.h
diff --git a/src/profile-generator.h b/src/profile-generator.h
index 7861ccd81785f3670a3d609ede6321717e0d5eac..6b02368816e540f10a45b1938822b713ab6d16e9 100644
--- a/src/profile-generator.h
+++ b/src/profile-generator.h
@@ -203,11 +203,13 @@ class ProfileTree {
 
 class CpuProfile {
  public:
-  CpuProfile(const char* title, unsigned uid, bool record_samples);
+  CpuProfile(const char* title, unsigned uid, bool record_samples)
+      : title_(title), uid_(uid), record_samples_(record_samples) { }
 
   // Add pc -> ... -> main() call path to the profile.
   void AddPath(const Vector<CodeEntry*>& path);
-  void CalculateTotalTicksAndSamplingRate();
+  void CalculateTotalTicks();
+  void SetActualSamplingRate(double actual_sampling_rate);
 
   INLINE(const char* title() const) { return title_; }
   INLINE(unsigned uid() const) { return uid_; }
@@ -225,8 +227,6 @@ class CpuProfile {
   const char* title_;
   unsigned uid_;
   bool record_samples_;
-  double start_time_ms_;
-  double end_time_ms_;
   List<ProfileNode*> samples_;
   ProfileTree top_down_;
 
@@ -286,7 +286,7 @@ class CpuProfilesCollection {
   ~CpuProfilesCollection();
 
   bool StartProfiling(const char* title, unsigned uid, bool record_samples);
-  CpuProfile* StopProfiling(const char* title);
+  CpuProfile* StopProfiling(const char* title, double actual_sampling_rate);
   List<CpuProfile*>* profiles() { return &finished_profiles_; }
   const char* GetName(Name* name) {
     return function_and_resource_names_.GetName(name);
@@ -329,6 +329,44 @@ class CpuProfilesCollection {
 };
 
 
+class SampleRateCalculator {
+ public:
+  SampleRateCalculator()
+      : result_(Logger::kSamplingIntervalMs * kResultScale),
+        ticks_per_ms_(Logger::kSamplingIntervalMs),
+        measurements_count_(0),
+        wall_time_query_countdown_(1) {
+  }
+
+  double ticks_per_ms() {
+    return result_ / static_cast<double>(kResultScale);
+  }
+  void Tick();
+  void UpdateMeasurements(double current_time);
+
+  // Instead of querying current wall time each tick,
+  // we use this constant to control query intervals.
+  static const unsigned kWallTimeQueryIntervalMs = 100;
+
+ private:
+  // As the result needs to be accessed from a different thread, we
+  // use type that guarantees atomic writes to memory.  There should
+  // be <= 1000 ticks per second, thus storing a value of a 10 ** 5
+  // order should provide enough precision while keeping away from a
+  // potential overflow.
+  static const int kResultScale = 100000;
+
+  AtomicWord result_;
+  // All other fields are accessed only from the sampler thread.
+  double ticks_per_ms_;
+  unsigned measurements_count_;
+  unsigned wall_time_query_countdown_;
+  double last_wall_time_;
+
+  DISALLOW_COPY_AND_ASSIGN(SampleRateCalculator);
+};
+
+
 class ProfileGenerator {
  public:
   explicit ProfileGenerator(CpuProfilesCollection* profiles);
@@ -337,6 +375,11 @@ class ProfileGenerator {
 
   INLINE(CodeMap* code_map()) { return &code_map_; }
 
+  INLINE(void Tick()) { sample_rate_calc_.Tick(); }
+  INLINE(double actual_sampling_rate()) {
+    return sample_rate_calc_.ticks_per_ms();
+  }
+
   static const char* const kAnonymousFunctionName;
   static const char* const kProgramEntryName;
   static const char* const kGarbageCollectorEntryName;
@@ -352,6 +395,7 @@ class ProfileGenerator {
   CodeEntry* program_entry_;
   CodeEntry* gc_entry_;
   CodeEntry* unresolved_entry_;
+  SampleRateCalculator sample_rate_calc_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileGenerator);
 };