Merge (7265, 7271] from bleeding_edge to experimental/gc branch....

src/runtime-profiler.h

 // Copyright 2010 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 10 matching lines @@
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #ifndef V8_RUNTIME_PROFILER_H_
 #define V8_RUNTIME_PROFILER_H_
 
-#include "v8.h"
 #include "allocation.h"
+#include "atomicops.h"
 
 namespace v8 {
 namespace internal {
 
-class RuntimeProfiler : public AllStatic {
- public:
-  static bool IsEnabled() { return V8::UseCrankshaft() && FLAG_opt; }
+class Isolate;
+class JSFunction;
+class Object;
+class PendingListNode;
+class Semaphore;
 
-  static void OptimizeNow();
-  static void OptimizeSoon(JSFunction* function);
 
-  static void NotifyTick();
-
-  static void Setup();
-  static void Reset();
-  static void TearDown();
-
-  static int SamplerWindowSize();
-  static void UpdateSamplesAfterScavenge();
-  static void RemoveDeadSamples();
-  static void UpdateSamplesAfterCompact(ObjectVisitor* visitor);
+enum SamplerState {
+  IN_NON_JS_STATE = 0,
+  IN_JS_STATE = 1
 };
 
 
+class RuntimeProfiler {
+ public:
+  explicit RuntimeProfiler(Isolate* isolate);
+
+  static bool IsEnabled();
+
+  void OptimizeNow();
+  void OptimizeSoon(JSFunction* function);
+
+  void NotifyTick();
+
+  void Setup();
+  void Reset();
+  void TearDown();
+
+  Object** SamplerWindowAddress();
+  int SamplerWindowSize();
+
+  // Rate limiting support.
+
+  // VM thread interface.
+  //
+  // Called by isolates when their states change.
+  static inline void IsolateEnteredJS(Isolate* isolate);
+  static inline void IsolateExitedJS(Isolate* isolate);
+
+  // 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();
+
+  // When shutting down we join the profiler thread. Doing so while
+  // it's waiting on a semaphore will cause a deadlock, so we have to
+  // wake it up first.
+  static void WakeUpRuntimeProfilerThreadBeforeShutdown();
+
+  void UpdateSamplesAfterScavenge();
+  void RemoveDeadSamples();
+  void UpdateSamplesAfterCompact(ObjectVisitor* visitor);
+
+ private:
+  static const int kSamplerWindowSize = 16;
+  static const int kStateWindowSize = 128;
+
+  static void HandleWakeUp(Isolate* isolate);
+
+  void Optimize(JSFunction* function, bool eager, int delay);
+
+  void AttemptOnStackReplacement(JSFunction* function);
+
+  void ClearSampleBuffer();
+
+  void ClearSampleBufferNewSpaceEntries();
+
+  int LookupSample(JSFunction* function);
+
+  void AddSample(JSFunction* function, int weight);
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  void UpdateStateRatio(SamplerState current_state);
+#endif
+
+  Isolate* isolate_;
+
+  int sampler_threshold_;
+  int sampler_threshold_size_factor_;
+  int sampler_ticks_until_threshold_adjustment_;
+
+  // The ratio of ticks spent in JS code in percent.
+  Atomic32 js_ratio_;
+
+  Object* sampler_window_[kSamplerWindowSize];
+  int sampler_window_position_;
+  int sampler_window_weight_[kSamplerWindowSize];
+
+  // Support for pending 'optimize soon' requests.
+  PendingListNode* optimize_soon_list_;
+
+  SamplerState state_window_[kStateWindowSize];
+  int state_window_position_;
+  int state_counts_[2];
+
+  // Possible state values:
+  //   -1            => the profiler thread is waiting on the semaphore
+  //   0 or positive => the number of isolates running JavaScript code.
+  static Atomic32 state_;
+  static Semaphore* semaphore_;
+};
+
+
 // Rate limiter intended to be used in the profiler thread.
 class RuntimeProfilerRateLimiter BASE_EMBEDDED {
  public:
   RuntimeProfilerRateLimiter() : non_js_ticks_(0) { }
 
-  // Suspends the current thread when not executing JavaScript to
-  // minimize CPU usage. Returns whether this thread was suspended
-  // (and so might have to check whether profiling is still active.)
+  // 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:
   int non_js_ticks_;
 
   DISALLOW_COPY_AND_ASSIGN(RuntimeProfilerRateLimiter);
 };
 
+
+// Implementation of RuntimeProfiler inline functions.
+
+void RuntimeProfiler::IsolateEnteredJS(Isolate* isolate) {
+  Atomic32 new_state = NoBarrier_AtomicIncrement(&state_, 1);
+  if (new_state == 0) {
+    // Just incremented from -1 to 0. -1 can only be set by the
+    // profiler thread before it suspends itself and starts waiting on
+    // the semaphore.
+    HandleWakeUp(isolate);
+  }
+  ASSERT(new_state >= 0);
+}
+
+
+void RuntimeProfiler::IsolateExitedJS(Isolate* isolate) {
+  Atomic32 new_state = NoBarrier_AtomicIncrement(&state_, -1);
+  ASSERT(new_state >= 0);
+  USE(new_state);
+}
+
 } }  // namespace v8::internal
 
 #endif  // V8_RUNTIME_PROFILER_H_