Support higher CPU profiler sampling rate on posix systems

src/sampler.cc

 // Copyright 2013 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 156 matching lines @@
   ThreadId profiled_thread_id_;
 };
 
 }  // namespace
 
 #if defined(USE_SIGNALS)
 
 class Sampler::PlatformData : public PlatformDataCommon {
  public:
   PlatformData() : vm_tid_(pthread_self()) {}
-  pthread_t vm_tid() const { return vm_tid_; }
+
+  void SendProfilingSignal() const;
 
  private:
   pthread_t vm_tid_;
 };
 
 #elif defined(__MACH__)
 
 class Sampler::PlatformData : public PlatformDataCommon {
  public:
   PlatformData() : profiled_thread_(mach_thread_self()) {}
@@ skipping 297 matching lines @@
         }
       }
       OS::Sleep(interval_);
     }
   }
 
  private:
 #if defined(USE_SIGNALS)
 
   void SampleContext(Sampler* sampler) {
-    if (!SignalHandler::Installed()) return;
-    pthread_t tid = sampler->platform_data()->vm_tid();
-    pthread_kill(tid, SIGPROF);
+    sampler->platform_data()->SendProfilingSignal();
   }
 
 #elif defined(__MACH__)
 
   void SampleContext(Sampler* sampler) {
     thread_act_t profiled_thread = sampler->platform_data()->profiled_thread();
 
 #if defined(USE_SIMULATOR)
     SimulatorHelper helper;
     Isolate* isolate = sampler->isolate();
@@ skipping 92 matching lines @@
   List<Sampler*> active_samplers_;
 
   DISALLOW_COPY_AND_ASSIGN(SamplerThread);
 };
 
 
 Mutex* SamplerThread::mutex_ = NULL;
 SamplerThread* SamplerThread::instance_ = NULL;
 
 
+#if defined(USE_SIGNALS)
+void Sampler::PlatformData::SendProfilingSignal() const {
+  if (!SignalHandler::Installed()) return;
+  pthread_kill(vm_tid_, SIGPROF);
+}
+#endif
+
+
 //
 // StackTracer implementation
 //
 DISABLE_ASAN void TickSample::Init(Isolate* isolate,
                                    const RegisterState& regs) {
   ASSERT(isolate->IsInitialized());
   pc = regs.pc;
   state = isolate->current_vm_state();
 
   // Avoid collecting traces while doing GC.
@@ skipping 38 matching lines @@
 
 void Sampler::TearDown() {
   SamplerThread::TearDown();
 }
 
 
 Sampler::Sampler(Isolate* isolate, int interval)
     : isolate_(isolate),
       interval_(interval),
       profiling_(false),
+      has_processing_thread_(false),
       active_(false),
       is_counting_samples_(false),
       js_and_external_sample_count_(0) {
   data_ = new PlatformData;
 }
 
 
 Sampler::~Sampler() {
   ASSERT(!IsActive());
   delete data_;
@@ skipping 20 matching lines @@
   if (sample == NULL) sample = &sample_obj;
   sample->Init(isolate_, state);
   if (is_counting_samples_) {
     if (sample->state == JS || sample->state == EXTERNAL) {
       ++js_and_external_sample_count_;
     }
   }
   Tick(sample);
 }
 
+
+bool Sampler::CanSampleOnProfilerEventsProcessorThread() {
+#if defined(USE_SIGNALS)
+  return true;
+#else
+  return false;
+#endif
+}
+
+
+void Sampler::DoSample() {
+#if defined(USE_SIGNALS)
+  platform_data()->SendProfilingSignal();
+#endif
+}
+
 } }  // namespace v8::internal