v8  10.1.124 (node 18.2.0)
V8 is Google's open source JavaScript engine
v8-tracing.h
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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_LIBPLATFORM_V8_TRACING_H_
6 #define V8_LIBPLATFORM_V8_TRACING_H_
7 
8 #include <atomic>
9 #include <fstream>
10 #include <memory>
11 #include <unordered_set>
12 #include <vector>
13 
14 #include "libplatform/libplatform-export.h"
15 #include "v8-platform.h" // NOLINT(build/include_directory)
16 
17 namespace perfetto {
18 namespace trace_processor {
19 class TraceProcessorStorage;
20 }
21 class TracingSession;
22 }
23 
24 namespace v8 {
25 
26 namespace base {
27 class Mutex;
28 } // namespace base
29 
30 namespace platform {
31 namespace tracing {
32 
33 class TraceEventListener;
34 
35 const int kTraceMaxNumArgs = 2;
36 
38  public:
39  union ArgValue {
40  uint64_t as_uint;
41  int64_t as_int;
42  double as_double;
43  const void* as_pointer;
44  const char* as_string;
45  };
46 
47  TraceObject() = default;
49  void Initialize(
50  char phase, const uint8_t* category_enabled_flag, const char* name,
51  const char* scope, uint64_t id, uint64_t bind_id, int num_args,
52  const char** arg_names, const uint8_t* arg_types,
53  const uint64_t* arg_values,
54  std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
55  unsigned int flags, int64_t timestamp, int64_t cpu_timestamp);
56  void UpdateDuration(int64_t timestamp, int64_t cpu_timestamp);
58  char phase, const uint8_t* category_enabled_flag, const char* name,
59  const char* scope, uint64_t id, uint64_t bind_id, int num_args,
60  const char** arg_names, const uint8_t* arg_types,
61  const uint64_t* arg_values,
62  std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
63  unsigned int flags, int pid, int tid, int64_t ts, int64_t tts,
64  uint64_t duration, uint64_t cpu_duration);
65 
66  int pid() const { return pid_; }
67  int tid() const { return tid_; }
68  char phase() const { return phase_; }
69  const uint8_t* category_enabled_flag() const {
70  return category_enabled_flag_;
71  }
72  const char* name() const { return name_; }
73  const char* scope() const { return scope_; }
74  uint64_t id() const { return id_; }
75  uint64_t bind_id() const { return bind_id_; }
76  int num_args() const { return num_args_; }
77  const char** arg_names() { return arg_names_; }
78  uint8_t* arg_types() { return arg_types_; }
79  ArgValue* arg_values() { return arg_values_; }
81  return arg_convertables_;
82  }
83  unsigned int flags() const { return flags_; }
84  int64_t ts() { return ts_; }
85  int64_t tts() { return tts_; }
86  uint64_t duration() { return duration_; }
87  uint64_t cpu_duration() { return cpu_duration_; }
88 
89  private:
90  int pid_;
91  int tid_;
92  char phase_;
93  const char* name_;
94  const char* scope_;
95  const uint8_t* category_enabled_flag_;
96  uint64_t id_;
97  uint64_t bind_id_;
98  int num_args_ = 0;
99  const char* arg_names_[kTraceMaxNumArgs];
100  uint8_t arg_types_[kTraceMaxNumArgs];
101  ArgValue arg_values_[kTraceMaxNumArgs];
102  std::unique_ptr<v8::ConvertableToTraceFormat>
103  arg_convertables_[kTraceMaxNumArgs];
104  char* parameter_copy_storage_ = nullptr;
105  unsigned int flags_;
106  int64_t ts_;
107  int64_t tts_;
108  uint64_t duration_;
109  uint64_t cpu_duration_;
110 
111  // Disallow copy and assign
112  TraceObject(const TraceObject&) = delete;
113  void operator=(const TraceObject&) = delete;
114 };
115 
117  public:
118  TraceWriter() = default;
119  virtual ~TraceWriter() = default;
120  virtual void AppendTraceEvent(TraceObject* trace_event) = 0;
121  virtual void Flush() = 0;
122 
123  static TraceWriter* CreateJSONTraceWriter(std::ostream& stream);
124  static TraceWriter* CreateJSONTraceWriter(std::ostream& stream,
125  const std::string& tag);
126 
128 
129  private:
130  // Disallow copy and assign
131  TraceWriter(const TraceWriter&) = delete;
132  void operator=(const TraceWriter&) = delete;
133 };
134 
136  public:
137  explicit TraceBufferChunk(uint32_t seq);
138 
139  void Reset(uint32_t new_seq);
140  bool IsFull() const { return next_free_ == kChunkSize; }
141  TraceObject* AddTraceEvent(size_t* event_index);
142  TraceObject* GetEventAt(size_t index) { return &chunk_[index]; }
143 
144  uint32_t seq() const { return seq_; }
145  size_t size() const { return next_free_; }
146 
147  static const size_t kChunkSize = 64;
148 
149  private:
150  size_t next_free_ = 0;
151  TraceObject chunk_[kChunkSize];
152  uint32_t seq_;
153 
154  // Disallow copy and assign
155  TraceBufferChunk(const TraceBufferChunk&) = delete;
156  void operator=(const TraceBufferChunk&) = delete;
157 };
158 
160  public:
161  TraceBuffer() = default;
162  virtual ~TraceBuffer() = default;
163 
164  virtual TraceObject* AddTraceEvent(uint64_t* handle) = 0;
165  virtual TraceObject* GetEventByHandle(uint64_t handle) = 0;
166  virtual bool Flush() = 0;
167 
168  static const size_t kRingBufferChunks = 1024;
169 
170  static TraceBuffer* CreateTraceBufferRingBuffer(size_t max_chunks,
171  TraceWriter* trace_writer);
172 
173  private:
174  // Disallow copy and assign
175  TraceBuffer(const TraceBuffer&) = delete;
176  void operator=(const TraceBuffer&) = delete;
177 };
178 
179 // Options determines how the trace buffer stores data.
181  // Record until the trace buffer is full.
183 
184  // Record until the user ends the trace. The trace buffer is a fixed size
185  // and we use it as a ring buffer during recording.
187 
188  // Record until the trace buffer is full, but with a huge buffer size.
190 
191  // Echo to console. Events are discarded.
193 };
194 
196  public:
197  typedef std::vector<std::string> StringList;
198 
200 
201  TraceConfig() : enable_systrace_(false), enable_argument_filter_(false) {}
202  TraceRecordMode GetTraceRecordMode() const { return record_mode_; }
204  return included_categories_;
205  }
206  bool IsSystraceEnabled() const { return enable_systrace_; }
207  bool IsArgumentFilterEnabled() const { return enable_argument_filter_; }
208 
209  void SetTraceRecordMode(TraceRecordMode mode) { record_mode_ = mode; }
210  void EnableSystrace() { enable_systrace_ = true; }
211  void EnableArgumentFilter() { enable_argument_filter_ = true; }
212 
213  void AddIncludedCategory(const char* included_category);
214 
215  bool IsCategoryGroupEnabled(const char* category_group) const;
216 
217  private:
218  TraceRecordMode record_mode_;
219  bool enable_systrace_ : 1;
220  bool enable_argument_filter_ : 1;
221  StringList included_categories_;
222 
223  // Disallow copy and assign
224  TraceConfig(const TraceConfig&) = delete;
225  void operator=(const TraceConfig&) = delete;
226 };
227 
228 #if defined(_MSC_VER)
229 #define V8_PLATFORM_NON_EXPORTED_BASE(code)
230  __pragma(warning(suppress : 4275)) code
231 #else
232 #define V8_PLATFORM_NON_EXPORTED_BASE(code) code
233 #endif // defined(_MSC_VER)
234 
237  public:
239  ~TracingController() override;
240 
241 #if defined(V8_USE_PERFETTO)
242  // Must be called before StartTracing() if V8_USE_PERFETTO is true. Provides
243  // the output stream for the JSON trace data.
245  // Provide an optional listener for testing that will receive trace events.
246  // Must be called before StartTracing().
248 #else // defined(V8_USE_PERFETTO)
249  // The pointer returned from GetCategoryGroupEnabled() points to a value with
250  // zero or more of the following bits. Used in this class only. The
251  // TRACE_EVENT macros should only use the value as a bool. These values must
252  // be in sync with macro values in TraceEvent.h in Blink.
254  // Category group enabled for the recording mode.
256  // Category group enabled by SetEventCallbackEnabled().
258  // Category group enabled to export events to ETW.
259  ENABLED_FOR_ETW_EXPORT = 1 << 3
260  };
261 
262  // Takes ownership of |trace_buffer|.
263  void Initialize(TraceBuffer* trace_buffer);
264 
265  // v8::TracingController implementation.
266  const uint8_t* GetCategoryGroupEnabled(const char* category_group) override;
267  uint64_t AddTraceEvent(
268  char phase, const uint8_t* category_enabled_flag, const char* name,
269  const char* scope, uint64_t id, uint64_t bind_id, int32_t num_args,
270  const char** arg_names, const uint8_t* arg_types,
271  const uint64_t* arg_values,
272  std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
273  unsigned int flags) override;
275  char phase, const uint8_t* category_enabled_flag, const char* name,
276  const char* scope, uint64_t id, uint64_t bind_id, int32_t num_args,
277  const char** arg_names, const uint8_t* arg_types,
278  const uint64_t* arg_values,
279  std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
280  unsigned int flags, int64_t timestamp) override;
281  void UpdateTraceEventDuration(const uint8_t* category_enabled_flag,
282  const char* name, uint64_t handle) override;
283 
284  static const char* GetCategoryGroupName(const uint8_t* category_enabled_flag);
285 #endif // !defined(V8_USE_PERFETTO)
286 
288  v8::TracingController::TraceStateObserver* observer) override;
290  v8::TracingController::TraceStateObserver* observer) override;
291 
292  void StartTracing(TraceConfig* trace_config);
293  void StopTracing();
294 
295  protected:
296 #if !defined(V8_USE_PERFETTO)
297  virtual int64_t CurrentTimestampMicroseconds();
299 #endif // !defined(V8_USE_PERFETTO)
300 
301  private:
302 #if !defined(V8_USE_PERFETTO)
303  void UpdateCategoryGroupEnabledFlag(size_t category_index);
304  void UpdateCategoryGroupEnabledFlags();
305 #endif // !defined(V8_USE_PERFETTO)
306 
307  std::unique_ptr<base::Mutex> mutex_;
308  std::unique_ptr<TraceConfig> trace_config_;
309  std::atomic_bool recording_{false};
310  std::unordered_set<v8::TracingController::TraceStateObserver*> observers_;
311 
312 #if defined(V8_USE_PERFETTO)
313  std::ostream* output_stream_ = nullptr;
318 #else // !defined(V8_USE_PERFETTO)
319  std::unique_ptr<TraceBuffer> trace_buffer_;
320 #endif // !defined(V8_USE_PERFETTO)
321 
322  // Disallow copy and assign
323  TracingController(const TracingController&) = delete;
324  void operator=(const TracingController&) = delete;
325 };
326 
327 #undef V8_PLATFORM_NON_EXPORTED_BASE
328 
329 } // namespace tracing
330 } // namespace platform
331 } // namespace v8
332 
333 #endif // V8_LIBPLATFORM_V8_TRACING_H_