| // Copyright 2013 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef V8_SAMPLER_H_ |
| #define V8_SAMPLER_H_ |
| |
| #include "include/v8.h" |
| |
| #include "src/base/atomicops.h" |
| #include "src/frames.h" |
| #include "src/globals.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. |
| |
| // TickSample captures the information collected for each sample. |
| struct TickSample { |
| // Internal profiling (with --prof + tools/$OS-tick-processor) wants to |
| // include the runtime function we're calling. Externally exposed tick |
| // samples don't care. |
| enum RecordCEntryFrame { kIncludeCEntryFrame, kSkipCEntryFrame }; |
| |
| 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 v8::RegisterState& state, |
| RecordCEntryFrame record_c_entry_frame); |
| static void GetStackSample(Isolate* isolate, const v8::RegisterState& state, |
| RecordCEntryFrame record_c_entry_frame, |
| void** frames, size_t frames_limit, |
| v8::SampleInfo* sample_info); |
| StateTag state; // The state of the VM. |
| Address pc; // Instruction pointer. |
| union { |
| Address tos; // Top stack value (*sp). |
| Address external_callback; |
| }; |
| static const unsigned kMaxFramesCountLog2 = 8; |
| static const unsigned kMaxFramesCount = (1 << kMaxFramesCountLog2) - 1; |
| Address stack[kMaxFramesCount]; // Call stack. |
| base::TimeTicks timestamp; |
| unsigned frames_count : kMaxFramesCountLog2; // 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 v8::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 base::NoBarrier_Load(&profiling_) > 0 && |
| !base::NoBarrier_Load(&has_processing_thread_); |
| } |
| void IncreaseProfilingDepth(); |
| void DecreaseProfilingDepth(); |
| |
| // Whether the sampler is running (that is, consumes resources). |
| bool IsActive() const { return base::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) { |
| base::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) { base::NoBarrier_Store(&active_, value); } |
| |
| Isolate* isolate_; |
| const int interval_; |
| base::Atomic32 profiling_; |
| base::Atomic32 has_processing_thread_; |
| base::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_ |