v8/src/sampler.h
yurys@chromium.org 7fc915b701 Do not start sampler thread when CpuProfiler is active
Now that CpuProfiler sends does sampling on the profile event processing thread there is no need to launch sampler thread. The latter is used only for --prof profiler.

BUG=v8:2814
R=bmeurer@chromium.org, svenpanne@chromium.org

Review URL: https://codereview.chromium.org/23011029

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16430 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2013-08-29 14:03:38 +00:00

151 lines
4.9 KiB
C++

// Copyright 2013 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_SAMPLER_H_
#define V8_SAMPLER_H_
#include "atomicops.h"
#include "frames.h"
#include "v8globals.h"
namespace v8 {
namespace internal {
class Isolate;
// ----------------------------------------------------------------------------
// Sampler
//
// A sampler periodically samples the state of the VM and optionally
// (if used for profiling) the program counter and stack pointer for
// the thread that created it.
struct RegisterState {
RegisterState() : pc(NULL), sp(NULL), fp(NULL) {}
Address pc; // Instruction pointer.
Address sp; // Stack pointer.
Address fp; // Frame pointer.
};
// TickSample captures the information collected for each sample.
struct TickSample {
TickSample()
: state(OTHER),
pc(NULL),
external_callback(NULL),
frames_count(0),
has_external_callback(false),
top_frame_type(StackFrame::NONE) {}
void Init(Isolate* isolate, const RegisterState& state);
StateTag state; // The state of the VM.
Address pc; // Instruction pointer.
union {
Address tos; // Top stack value (*sp).
Address external_callback;
};
static const int kMaxFramesCount = 64;
Address stack[kMaxFramesCount]; // Call stack.
int frames_count : 8; // Number of captured frames.
bool has_external_callback : 1;
StackFrame::Type top_frame_type : 4;
};
class Sampler {
public:
// Initializes the Sampler support. Called once at VM startup.
static void SetUp();
static void TearDown();
// Initialize sampler.
Sampler(Isolate* isolate, int interval);
virtual ~Sampler();
Isolate* isolate() const { return isolate_; }
int interval() const { return interval_; }
// Performs stack sampling.
void SampleStack(const RegisterState& regs);
// Start and stop sampler.
void Start();
void Stop();
// Whether the sampling thread should use this Sampler for CPU profiling?
bool IsProfiling() const {
return NoBarrier_Load(&profiling_) > 0 &&
!NoBarrier_Load(&has_processing_thread_);
}
void IncreaseProfilingDepth();
void DecreaseProfilingDepth();
// Whether the sampler is running (that is, consumes resources).
bool IsActive() const { return NoBarrier_Load(&active_); }
void DoSample();
// If true next sample must be initiated on the profiler event processor
// thread right after latest sample is processed.
void SetHasProcessingThread(bool value) {
NoBarrier_Store(&has_processing_thread_, value);
}
// Used in tests to make sure that stack sampling is performed.
unsigned js_and_external_sample_count() const {
return js_and_external_sample_count_;
}
void StartCountingSamples() {
is_counting_samples_ = true;
js_and_external_sample_count_ = 0;
}
class PlatformData;
PlatformData* platform_data() const { return data_; }
protected:
// This method is called for each sampling period with the current
// program counter.
virtual void Tick(TickSample* sample) = 0;
private:
void SetActive(bool value) { NoBarrier_Store(&active_, value); }
Isolate* isolate_;
const int interval_;
Atomic32 profiling_;
Atomic32 has_processing_thread_;
Atomic32 active_;
PlatformData* data_; // Platform specific data.
bool is_counting_samples_;
// Counts stack samples taken in JS VM state.
unsigned js_and_external_sample_count_;
DISALLOW_IMPLICIT_CONSTRUCTORS(Sampler);
};
} } // namespace v8::internal
#endif // V8_SAMPLER_H_