OLD | NEW |
| (Empty) |
1 // Copyright 2016 the V8 project authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #ifndef V8_LIBSAMPLER_SAMPLER_H_ | |
6 #define V8_LIBSAMPLER_SAMPLER_H_ | |
7 | |
8 #include "include/v8.h" | |
9 | |
10 #include "src/base/atomicops.h" | |
11 #include "src/base/macros.h" | |
12 | |
13 namespace v8 { | |
14 namespace sampler { | |
15 | |
16 // ---------------------------------------------------------------------------- | |
17 // Sampler | |
18 // | |
19 // A sampler periodically samples the state of the VM and optionally | |
20 // (if used for profiling) the program counter and stack pointer for | |
21 // the thread that created it. | |
22 | |
23 class Sampler { | |
24 public: | |
25 static const int kMaxFramesCountLog2 = 8; | |
26 static const unsigned kMaxFramesCount = (1u << kMaxFramesCountLog2) - 1; | |
27 | |
28 // Initializes the Sampler support. Called once at VM startup. | |
29 static void SetUp(); | |
30 static void TearDown(); | |
31 | |
32 // Initialize sampler. | |
33 explicit Sampler(Isolate* isolate); | |
34 virtual ~Sampler(); | |
35 | |
36 Isolate* isolate() const { return isolate_; } | |
37 | |
38 // Performs stack sampling. | |
39 // Clients should override this method in order to do something on samples, | |
40 // for example buffer samples in a queue. | |
41 virtual void SampleStack(const v8::RegisterState& regs) = 0; | |
42 | |
43 // Start and stop sampler. | |
44 void Start(); | |
45 void Stop(); | |
46 | |
47 // Whether the sampling thread should use this Sampler for CPU profiling? | |
48 bool IsProfiling() const { | |
49 return base::NoBarrier_Load(&profiling_) > 0 && | |
50 !base::NoBarrier_Load(&has_processing_thread_); | |
51 } | |
52 void IncreaseProfilingDepth(); | |
53 void DecreaseProfilingDepth(); | |
54 | |
55 // Whether the sampler is running (that is, consumes resources). | |
56 bool IsActive() const { return base::NoBarrier_Load(&active_); } | |
57 | |
58 // CpuProfiler collects samples by calling DoSample directly | |
59 // without calling Start. To keep it working, we register the sampler | |
60 // with the CpuProfiler. | |
61 bool IsRegistered() const { return base::NoBarrier_Load(®istered_); } | |
62 | |
63 void DoSample(); | |
64 | |
65 void SetHasProcessingThread(bool value) { | |
66 base::NoBarrier_Store(&has_processing_thread_, value); | |
67 } | |
68 | |
69 // Used in tests to make sure that stack sampling is performed. | |
70 unsigned js_sample_count() const { return js_sample_count_; } | |
71 unsigned external_sample_count() const { return external_sample_count_; } | |
72 void StartCountingSamples() { | |
73 js_sample_count_ = 0; | |
74 external_sample_count_ = 0; | |
75 is_counting_samples_ = true; | |
76 } | |
77 | |
78 class PlatformData; | |
79 PlatformData* platform_data() const { return data_; } | |
80 | |
81 protected: | |
82 // Counts stack samples taken in various VM states. | |
83 bool is_counting_samples_; | |
84 unsigned js_sample_count_; | |
85 unsigned external_sample_count_; | |
86 | |
87 private: | |
88 void SetActive(bool value) { base::NoBarrier_Store(&active_, value); } | |
89 void SetRegistered(bool value) { base::NoBarrier_Store(®istered_, value); } | |
90 | |
91 Isolate* isolate_; | |
92 base::Atomic32 profiling_; | |
93 base::Atomic32 has_processing_thread_; | |
94 base::Atomic32 active_; | |
95 base::Atomic32 registered_; | |
96 PlatformData* data_; // Platform specific data. | |
97 DISALLOW_IMPLICIT_CONSTRUCTORS(Sampler); | |
98 }; | |
99 | |
100 } // namespace sampler | |
101 } // namespace v8 | |
102 | |
103 #endif // V8_LIBSAMPLER_SAMPLER_H_ | |
OLD | NEW |