Use count-based profiling exclusively.

src/platform-linux.cc

 // 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 1073 matching lines @@
 
   int vm_tid() const { return vm_tid_; }
 
  private:
   const int vm_tid_;
 };
 
 
 class SignalSender : public Thread {
  public:
-  enum SleepInterval {
-    HALF_INTERVAL,
-    FULL_INTERVAL
-  };
-
   static const int kSignalSenderStackSize = 64 * KB;
 
   explicit SignalSender(int interval)
       : Thread(Thread::Options("SignalSender", kSignalSenderStackSize)),
         vm_tgid_(getpid()),
         interval_(interval) {}
 
   static void SetUp() { if (!mutex_) mutex_ = OS::CreateMutex(); }
   static void TearDown() { delete mutex_; }
 
@@ skipping 35 matching lines @@
       instance_ = NULL;
       RestoreSignalHandler();
     }
   }
 
   // Implement Thread::Run().
   virtual void Run() {
     SamplerRegistry::State state;
     while ((state = SamplerRegistry::GetState()) !=
            SamplerRegistry::HAS_NO_SAMPLERS) {
-      bool cpu_profiling_enabled =
-          (state == SamplerRegistry::HAS_CPU_PROFILING_SAMPLERS);
-      bool runtime_profiler_enabled = RuntimeProfiler::IsEnabled();
-      if (cpu_profiling_enabled && !signal_handler_installed_) {
-        InstallSignalHandler();
-      } else if (!cpu_profiling_enabled && signal_handler_installed_) {
-        RestoreSignalHandler();
-      }
       // When CPU profiling is enabled both JavaScript and C++ code is
       // profiled. We must not suspend.
-      if (!cpu_profiling_enabled) {
+      if (state == SamplerRegistry::HAS_CPU_PROFILING_SAMPLERS) {
+        if (!signal_handler_installed_) InstallSignalHandler();
+        SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this);
+      } else {
+        if (signal_handler_installed_) RestoreSignalHandler();
         if (rate_limiter_.SuspendIfNecessary()) continue;
       }
-      if (cpu_profiling_enabled && runtime_profiler_enabled) {
-        if (!SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this)) {
-          return;
-        }
-        Sleep(HALF_INTERVAL);
-        if (!SamplerRegistry::IterateActiveSamplers(&DoRuntimeProfile, NULL)) {
-          return;
-        }
-        Sleep(HALF_INTERVAL);
-      } else {
-        if (cpu_profiling_enabled) {
-          if (!SamplerRegistry::IterateActiveSamplers(&DoCpuProfile,
-                                                      this)) {
-            return;
-          }
-        }
-        if (runtime_profiler_enabled) {
-          if (!SamplerRegistry::IterateActiveSamplers(&DoRuntimeProfile,
-                                                      NULL)) {
-            return;
-          }
-        }
-        Sleep(FULL_INTERVAL);
-      }
+      Sleep();  // TODO(svenpanne) Figure out if OS:Sleep(interval_) is enough.
     }
   }
 
   static void DoCpuProfile(Sampler* sampler, void* raw_sender) {
     if (!sampler->IsProfiling()) return;
     SignalSender* sender = reinterpret_cast<SignalSender*>(raw_sender);
     sender->SendProfilingSignal(sampler->platform_data()->vm_tid());
   }
 
-  static void DoRuntimeProfile(Sampler* sampler, void* ignored) {
-    if (!sampler->isolate()->IsInitialized()) return;
-    sampler->isolate()->runtime_profiler()->NotifyTick();
-  }
-
   void SendProfilingSignal(int tid) {
     if (!signal_handler_installed_) return;
     // Glibc doesn't provide a wrapper for tgkill(2).
 #if defined(ANDROID)
     syscall(__NR_tgkill, vm_tgid_, tid, SIGPROF);
 #else
     syscall(SYS_tgkill, vm_tgid_, tid, SIGPROF);
 #endif
   }
 
-  void Sleep(SleepInterval full_or_half) {
+  void Sleep() {
     // Convert ms to us and subtract 100 us to compensate delays
     // occuring during signal delivery.
     useconds_t interval = interval_ * 1000 - 100;
-    if (full_or_half == HALF_INTERVAL) interval /= 2;
 #if defined(ANDROID)
     usleep(interval);
 #else
     int result = usleep(interval);
 #ifdef DEBUG
     if (result != 0 && errno != EINTR) {
       fprintf(stderr,
               "SignalSender usleep error; interval = %u, errno = %d\n",
               interval,
               errno);
@@ skipping 83 matching lines @@
 
 
 void Sampler::Stop() {
   ASSERT(IsActive());
   SignalSender::RemoveActiveSampler(this);
   SetActive(false);
 }
 
 
 } }  // namespace v8::internal