Use count-based profiling exclusively.

src/platform-linux.cc

Index: src/platform-linux.cc
diff --git a/src/platform-linux.cc b/src/platform-linux.cc
index ec48d6305e3de2ea4b51f0571a1c7a83bb0ae619..7a186413b5f3c7c059fd9e09f50abd7490dbedbf 100644
--- a/src/platform-linux.cc
+++ b/src/platform-linux.cc
@@ -1091,11 +1091,6 @@ class Sampler::PlatformData : public Malloced {
 
 class SignalSender : public Thread {
  public:
-  enum SleepInterval {
-    HALF_INTERVAL,
-    FULL_INTERVAL
-  };
-
   static const int kSignalSenderStackSize = 64 * KB;
 
   explicit SignalSender(int interval)
@@ -1151,43 +1146,16 @@ class SignalSender : public Thread {
     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 (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);
+      if (state == SamplerRegistry::HAS_CPU_PROFILING_SAMPLERS) {
+        if (!signal_handler_installed_) InstallSignalHandler();
+        SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this);
       } else {
-        if (cpu_profiling_enabled) {
-          if (!SamplerRegistry::IterateActiveSamplers(&DoCpuProfile,
-                                                      this)) {
-            return;
-          }
-        }
-        if (runtime_profiler_enabled) {
-          if (!SamplerRegistry::IterateActiveSamplers(&DoRuntimeProfile,
-                                                      NULL)) {
-            return;
-          }
-        }
-        Sleep(FULL_INTERVAL);
+        if (signal_handler_installed_) RestoreSignalHandler();
+        if (rate_limiter_.SuspendIfNecessary()) continue;
       }
+      Sleep();  // TODO(svenpanne) Figure out if OS:Sleep(interval_) is enough.
     }
   }
 
@@ -1197,11 +1165,6 @@ class SignalSender : public Thread {
     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).
@@ -1212,11 +1175,10 @@ class SignalSender : public Thread {
 #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