Support higher CPU profiler sampling rate on posix systems

src/cpu-profiler.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 122 matching lines @@
     CODE_EVENTS_TYPE_LIST(DECLARE_CLASS)
 #undef DECLARE_TYPE
   };
 };
 
 
 // This class implements both the profile events processor thread and
 // methods called by event producers: VM and stack sampler threads.
 class ProfilerEventsProcessor : public Thread {
  public:
-  explicit ProfilerEventsProcessor(ProfileGenerator* generator);
+  ProfilerEventsProcessor(ProfileGenerator* generator,
+                          Sampler* sampler,
+                          int period_in_useconds);
   virtual ~ProfilerEventsProcessor() {}
 
   // Thread control.
   virtual void Run();
   void StopSynchronously();
   INLINE(bool running()) { return running_; }
   void Enqueue(const CodeEventsContainer& event);
 
   // Puts current stack into tick sample events buffer.
   void AddCurrentStack(Isolate* isolate);
 
   // 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.
   INLINE(TickSample* TickSampleEvent());
 
  private:
   // Called from events processing thread (Run() method.)
   bool ProcessCodeEvent();
   bool ProcessTicks();
 
+  void ProcessEventsAndDoSample();
+  void ProcessEventsAndYield();
+
   ProfileGenerator* generator_;
+  Sampler* sampler_;
   bool running_;
+  // Sampling period in microseconds.
+  const int period_in_useconds_;
   UnboundQueue<CodeEventsContainer> events_buffer_;
   SamplingCircularQueue ticks_buffer_;
   UnboundQueue<TickSampleEventRecord> ticks_from_vm_buffer_;
   unsigned last_code_event_id_;
   unsigned last_processed_code_event_id_;
 };
 
 
 #define PROFILE(IsolateGetter, Call)                                        \
   do {                                                                      \
@@ skipping 81 matching lines @@
   bool need_to_stop_sampler_;
   bool is_profiling_;
 
   DISALLOW_COPY_AND_ASSIGN(CpuProfiler);
 };
 
 } }  // namespace v8::internal
 
 
 #endif  // V8_CPU_PROFILER_H_