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// 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
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// 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 "allocation.h"
#include "atomicops.h"
namespace v8 {
namespace internal {
class Isolate;
class JSFunction;
class Object;
class Semaphore;
class RuntimeProfiler {
public:
explicit RuntimeProfiler(Isolate* isolate);
static void GlobalSetUp();
static inline bool IsEnabled() {
ASSERT(has_been_globally_set_up_);
return enabled_;
}
void OptimizeNow();
void NotifyTick();
void SetUp();
void Reset();
void TearDown();
Object** SamplerWindowAddress();
int SamplerWindowSize();
void NotifyICChanged() { any_ic_changed_ = true; }
// 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();
// Stops the runtime profiler thread when profiling support is being
// turned off.
static void StopRuntimeProfilerThreadBeforeShutdown(Thread* thread);
void UpdateSamplesAfterScavenge();
void RemoveDeadSamples();
void UpdateSamplesAfterCompact(ObjectVisitor* visitor);
void AttemptOnStackReplacement(JSFunction* function);
private:
static const int kSamplerWindowSize = 16;
static void HandleWakeUp(Isolate* isolate);
void Optimize(JSFunction* function, const char* reason);
void ClearSampleBuffer();
void ClearSampleBufferNewSpaceEntries();
int LookupSample(JSFunction* function);
void AddSample(JSFunction* function, int weight);
Isolate* isolate_;
int sampler_threshold_;
int sampler_threshold_size_factor_;
int sampler_ticks_until_threshold_adjustment_;
Object* sampler_window_[kSamplerWindowSize];
int sampler_window_position_;
int sampler_window_weight_[kSamplerWindowSize];
bool any_ic_changed_;
bool code_generated_;
// 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_;
#ifdef DEBUG
static bool has_been_globally_set_up_;
#endif
static bool enabled_;
};
// 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) {
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_
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