Removed RuntimeProfilerRateLimiter class and RuntimeProfiler::IsSomeIsolateInJS.

Removing the former was basically a consequence of removing the latter. The net
effect is, apart from less code, that the signal sender thread is much more
explicit about its logic now.

Review URL: https://codereview.chromium.org/11543020

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13212 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/isolate.h

@@ -1015,7 +1015,6 @@ class Isolate {
         RuntimeProfiler::IsolateEnteredJS(this);
       } else if (current_state == JS && state != JS) {
         // JS -> non-JS transition.
-        ASSERT(RuntimeProfiler::IsSomeIsolateInJS());
         RuntimeProfiler::IsolateExitedJS(this);
       } else {
         // Other types of state transitions are not interesting to the

src/platform-cygwin.cc

@@ -660,7 +660,7 @@ class SamplerThread : public Thread {
       if (state == SamplerRegistry::HAS_CPU_PROFILING_SAMPLERS) {
         SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this);
       } else {
-        if (rate_limiter_.SuspendIfNecessary()) continue;
+        if (RuntimeProfiler::WaitForSomeIsolateToEnterJS()) continue;
       }
       OS::Sleep(interval_);
     }
@@ -708,7 +708,6 @@ class SamplerThread : public Thread {
   }
 
   const int interval_;
-  RuntimeProfilerRateLimiter rate_limiter_;
 
   // Protects the process wide state below.
   static Mutex* mutex_;

src/platform-freebsd.cc

@@ -767,7 +767,7 @@ class SignalSender : public Thread {
       if (state == SamplerRegistry::HAS_CPU_PROFILING_SAMPLERS) {
         SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this);
       } else {
-        if (rate_limiter_.SuspendIfNecessary()) continue;
+        if (RuntimeProfiler::WaitForSomeIsolateToEnterJS()) continue;
       }
       Sleep();  // TODO(svenpanne) Figure out if OS:Sleep(interval_) is enough.
     }
@@ -802,7 +802,6 @@ class SignalSender : public Thread {
   }
 
   const int interval_;
-  RuntimeProfilerRateLimiter rate_limiter_;
 
   // Protects the process wide state below.
   static Mutex* mutex_;

src/platform-linux.cc

@@ -1153,7 +1153,7 @@ class SignalSender : public Thread {
         SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this);
       } else {
         if (signal_handler_installed_) RestoreSignalHandler();
-        if (rate_limiter_.SuspendIfNecessary()) continue;
+        if (RuntimeProfiler::WaitForSomeIsolateToEnterJS()) continue;
       }
       Sleep();  // TODO(svenpanne) Figure out if OS:Sleep(interval_) is enough.
     }
@@ -1198,7 +1198,6 @@ class SignalSender : public Thread {
 
   const int vm_tgid_;
   const int interval_;
-  RuntimeProfilerRateLimiter rate_limiter_;
 
   // Protects the process wide state below.
   static Mutex* mutex_;

src/platform-macos.cc

@@ -792,7 +792,7 @@ class SamplerThread : public Thread {
       if (state == SamplerRegistry::HAS_CPU_PROFILING_SAMPLERS) {
         SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this);
       } else {
-        if (rate_limiter_.SuspendIfNecessary()) continue;
+        if (RuntimeProfiler::WaitForSomeIsolateToEnterJS()) continue;
       }
       OS::Sleep(interval_);
     }
@@ -851,7 +851,6 @@ class SamplerThread : public Thread {
   }
 
   const int interval_;
-  RuntimeProfilerRateLimiter rate_limiter_;
 
   // Protects the process wide state below.
   static Mutex* mutex_;

src/platform-openbsd.cc

@@ -846,7 +846,7 @@ class SignalSender : public Thread {
         SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this);
       } else {
         if (signal_handler_installed_) RestoreSignalHandler();
-        if (rate_limiter_.SuspendIfNecessary()) continue;
+        if (RuntimeProfiler::WaitForSomeIsolateToEnterJS()) continue;
       }
       Sleep();  // TODO(svenpanne) Figure out if OS:Sleep(interval_) is enough.
     }
@@ -882,7 +882,6 @@ class SignalSender : public Thread {
 
   const int vm_tgid_;
   const int interval_;
-  RuntimeProfilerRateLimiter rate_limiter_;
 
   // Protects the process wide state below.
   static Mutex* mutex_;

src/platform-solaris.cc

@@ -762,7 +762,7 @@ class SignalSender : public Thread {
         SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this);
       } else {
         if (signal_handler_installed_) RestoreSignalHandler();
-        if (rate_limiter_.SuspendIfNecessary()) continue;
+        if (RuntimeProfiler::WaitForSomeIsolateToEnterJS()) continue;
       }
       Sleep();  // TODO(svenpanne) Figure out if OS:Sleep(interval_) is enough.
     }
@@ -797,7 +797,6 @@ class SignalSender : public Thread {
   }
 
   const int interval_;
-  RuntimeProfilerRateLimiter rate_limiter_;
 
   // Protects the process wide state below.
   static Mutex* mutex_;

src/platform-win32.cc

@@ -2015,7 +2015,7 @@ class SamplerThread : public Thread {
       if (state == SamplerRegistry::HAS_CPU_PROFILING_SAMPLERS) {
         SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this);
       } else {
-        if (rate_limiter_.SuspendIfNecessary()) continue;
+        if (RuntimeProfiler::WaitForSomeIsolateToEnterJS()) continue;
       }
       OS::Sleep(interval_);
     }
@@ -2063,7 +2063,6 @@ class SamplerThread : public Thread {
   }
 
   const int interval_;
-  RuntimeProfilerRateLimiter rate_limiter_;
 
   // Protects the process wide state below.
   static Mutex* mutex_;

src/runtime-profiler.cc

@@ -430,11 +430,6 @@ void RuntimeProfiler::HandleWakeUp(Isolate* isolate) {
 }
 
 
-bool RuntimeProfiler::IsSomeIsolateInJS() {
-  return NoBarrier_Load(&state_) > 0;
-}
-
-
 bool RuntimeProfiler::WaitForSomeIsolateToEnterJS() {
   Atomic32 old_state = NoBarrier_CompareAndSwap(&state_, 0, -1);
   ASSERT(old_state >= -1);
@@ -484,12 +479,4 @@ void RuntimeProfiler::UpdateSamplesAfterCompact(ObjectVisitor* visitor) {
 }
 
 
-bool RuntimeProfilerRateLimiter::SuspendIfNecessary() {
-  if (!RuntimeProfiler::IsSomeIsolateInJS()) {
-    return RuntimeProfiler::WaitForSomeIsolateToEnterJS();
-  }
-  return false;
-}
-
-
 } }  // namespace v8::internal

src/runtime-profiler.h

@@ -71,17 +71,12 @@ class RuntimeProfiler {
 
   // Profiler thread interface.
   //
-  // IsSomeIsolateInJS():
-  // The profiler thread can query whether some isolate is currently
-  // running JavaScript code.
-  //
   // WaitForSomeIsolateToEnterJS():
   // When no isolates are running JavaScript code for some time the
   // profiler thread suspends itself by calling the wait function. The
   // wait function returns true after it waited or false immediately.
   // While the function was waiting the profiler may have been
   // disabled so it *must check* whether it is allowed to continue.
-  static bool IsSomeIsolateInJS();
   static bool WaitForSomeIsolateToEnterJS();
 
   // Stops the runtime profiler thread when profiling support is being
@@ -134,24 +129,6 @@ class RuntimeProfiler {
 };
 
 
-// Rate limiter intended to be used in the profiler thread.
-class RuntimeProfilerRateLimiter BASE_EMBEDDED {
- public:
-  RuntimeProfilerRateLimiter() {}
-
-  // Suspends the current thread (which must be the profiler thread)
-  // when not executing JavaScript to minimize CPU usage. Returns
-  // whether the thread was suspended (and so must check whether
-  // profiling is still active.)
-  //
-  // Does nothing when runtime profiling is not enabled.
-  bool SuspendIfNecessary();
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(RuntimeProfilerRateLimiter);
-};
-
-
 // Implementation of RuntimeProfiler inline functions.
 
 void RuntimeProfiler::IsolateEnteredJS(Isolate* isolate) {