OLD | NEW |
| (Empty) |
1 /* | |
2 * Copyright (c) 2012 The WebRTC project authors. All Rights Reserved. | |
3 * | |
4 * Use of this source code is governed by a BSD-style license | |
5 * that can be found in the LICENSE file in the root of the source | |
6 * tree. An additional intellectual property rights grant can be found | |
7 * in the file PATENTS. All contributing project authors may | |
8 * be found in the AUTHORS file in the root of the source tree. | |
9 */ | |
10 #include "webrtc/base/event_tracer.h" | |
11 | |
12 #include <inttypes.h> | |
13 | |
14 #include <string> | |
15 #include <vector> | |
16 | |
17 #include "webrtc/base/checks.h" | |
18 #include "webrtc/base/criticalsection.h" | |
19 #include "webrtc/base/event.h" | |
20 #include "webrtc/base/logging.h" | |
21 #include "webrtc/base/platform_thread.h" | |
22 #include "webrtc/base/stringutils.h" | |
23 #include "webrtc/base/timeutils.h" | |
24 #include "webrtc/base/trace_event.h" | |
25 | |
26 // This is a guesstimate that should be enough in most cases. | |
27 static const size_t kEventLoggerArgsStrBufferInitialSize = 256; | |
28 static const size_t kTraceArgBufferLength = 32; | |
29 | |
30 namespace webrtc { | |
31 | |
32 namespace { | |
33 | |
34 GetCategoryEnabledPtr g_get_category_enabled_ptr = nullptr; | |
35 AddTraceEventPtr g_add_trace_event_ptr = nullptr; | |
36 | |
37 } // namespace | |
38 | |
39 void SetupEventTracer(GetCategoryEnabledPtr get_category_enabled_ptr, | |
40 AddTraceEventPtr add_trace_event_ptr) { | |
41 g_get_category_enabled_ptr = get_category_enabled_ptr; | |
42 g_add_trace_event_ptr = add_trace_event_ptr; | |
43 } | |
44 | |
45 const unsigned char* EventTracer::GetCategoryEnabled(const char* name) { | |
46 if (g_get_category_enabled_ptr) | |
47 return g_get_category_enabled_ptr(name); | |
48 | |
49 // A string with null terminator means category is disabled. | |
50 return reinterpret_cast<const unsigned char*>("\0"); | |
51 } | |
52 | |
53 // Arguments to this function (phase, etc.) are as defined in | |
54 // webrtc/base/trace_event.h. | |
55 void EventTracer::AddTraceEvent(char phase, | |
56 const unsigned char* category_enabled, | |
57 const char* name, | |
58 unsigned long long id, | |
59 int num_args, | |
60 const char** arg_names, | |
61 const unsigned char* arg_types, | |
62 const unsigned long long* arg_values, | |
63 unsigned char flags) { | |
64 if (g_add_trace_event_ptr) { | |
65 g_add_trace_event_ptr(phase, | |
66 category_enabled, | |
67 name, | |
68 id, | |
69 num_args, | |
70 arg_names, | |
71 arg_types, | |
72 arg_values, | |
73 flags); | |
74 } | |
75 } | |
76 | |
77 } // namespace webrtc | |
78 | |
79 namespace rtc { | |
80 namespace tracing { | |
81 namespace { | |
82 | |
83 static void EventTracingThreadFunc(void* params); | |
84 | |
85 // Atomic-int fast path for avoiding logging when disabled. | |
86 static volatile int g_event_logging_active = 0; | |
87 | |
88 // TODO(pbos): Log metadata for all threads, etc. | |
89 class EventLogger final { | |
90 public: | |
91 EventLogger() | |
92 : logging_thread_(EventTracingThreadFunc, | |
93 this, | |
94 "EventTracingThread", | |
95 kLowPriority), | |
96 shutdown_event_(false, false) {} | |
97 ~EventLogger() { RTC_DCHECK(thread_checker_.CalledOnValidThread()); } | |
98 | |
99 void AddTraceEvent(const char* name, | |
100 const unsigned char* category_enabled, | |
101 char phase, | |
102 int num_args, | |
103 const char** arg_names, | |
104 const unsigned char* arg_types, | |
105 const unsigned long long* arg_values, | |
106 uint64_t timestamp, | |
107 int pid, | |
108 rtc::PlatformThreadId thread_id) { | |
109 std::vector<TraceArg> args(num_args); | |
110 for (int i = 0; i < num_args; ++i) { | |
111 TraceArg& arg = args[i]; | |
112 arg.name = arg_names[i]; | |
113 arg.type = arg_types[i]; | |
114 arg.value.as_uint = arg_values[i]; | |
115 | |
116 // Value is a pointer to a temporary string, so we have to make a copy. | |
117 if (arg.type == TRACE_VALUE_TYPE_COPY_STRING) { | |
118 // Space for the string and for the terminating null character. | |
119 size_t str_length = strlen(arg.value.as_string) + 1; | |
120 char* str_copy = new char[str_length]; | |
121 memcpy(str_copy, arg.value.as_string, str_length); | |
122 arg.value.as_string = str_copy; | |
123 } | |
124 } | |
125 rtc::CritScope lock(&crit_); | |
126 trace_events_.push_back( | |
127 {name, category_enabled, phase, args, timestamp, 1, thread_id}); | |
128 } | |
129 | |
130 // The TraceEvent format is documented here: | |
131 // https://docs.google.com/document/d/1CvAClvFfyA5R-PhYUmn5OOQtYMH4h6I0nSsKchNAy
SU/preview | |
132 void Log() { | |
133 RTC_DCHECK(output_file_); | |
134 static const int kLoggingIntervalMs = 100; | |
135 fprintf(output_file_, "{ \"traceEvents\": [\n"); | |
136 bool has_logged_event = false; | |
137 while (true) { | |
138 bool shutting_down = shutdown_event_.Wait(kLoggingIntervalMs); | |
139 std::vector<TraceEvent> events; | |
140 { | |
141 rtc::CritScope lock(&crit_); | |
142 trace_events_.swap(events); | |
143 } | |
144 std::string args_str; | |
145 args_str.reserve(kEventLoggerArgsStrBufferInitialSize); | |
146 for (TraceEvent& e : events) { | |
147 args_str.clear(); | |
148 if (!e.args.empty()) { | |
149 args_str += ", \"args\": {"; | |
150 bool is_first_argument = true; | |
151 for (TraceArg& arg : e.args) { | |
152 if (!is_first_argument) | |
153 args_str += ","; | |
154 is_first_argument = false; | |
155 args_str += " \""; | |
156 args_str += arg.name; | |
157 args_str += "\": "; | |
158 args_str += TraceArgValueAsString(arg); | |
159 | |
160 // Delete our copy of the string. | |
161 if (arg.type == TRACE_VALUE_TYPE_COPY_STRING) { | |
162 delete[] arg.value.as_string; | |
163 arg.value.as_string = nullptr; | |
164 } | |
165 } | |
166 args_str += " }"; | |
167 } | |
168 fprintf(output_file_, | |
169 "%s{ \"name\": \"%s\"" | |
170 ", \"cat\": \"%s\"" | |
171 ", \"ph\": \"%c\"" | |
172 ", \"ts\": %" PRIu64 | |
173 ", \"pid\": %d" | |
174 #if defined(WEBRTC_WIN) | |
175 ", \"tid\": %lu" | |
176 #else | |
177 ", \"tid\": %d" | |
178 #endif // defined(WEBRTC_WIN) | |
179 "%s" | |
180 "}\n", | |
181 has_logged_event ? "," : " ", e.name, e.category_enabled, | |
182 e.phase, e.timestamp, e.pid, e.tid, args_str.c_str()); | |
183 has_logged_event = true; | |
184 } | |
185 if (shutting_down) | |
186 break; | |
187 } | |
188 fprintf(output_file_, "]}\n"); | |
189 if (output_file_owned_) | |
190 fclose(output_file_); | |
191 output_file_ = nullptr; | |
192 } | |
193 | |
194 void Start(FILE* file, bool owned) { | |
195 RTC_DCHECK(thread_checker_.CalledOnValidThread()); | |
196 RTC_DCHECK(file); | |
197 RTC_DCHECK(!output_file_); | |
198 output_file_ = file; | |
199 output_file_owned_ = owned; | |
200 { | |
201 rtc::CritScope lock(&crit_); | |
202 // Since the atomic fast-path for adding events to the queue can be | |
203 // bypassed while the logging thread is shutting down there may be some | |
204 // stale events in the queue, hence the vector needs to be cleared to not | |
205 // log events from a previous logging session (which may be days old). | |
206 trace_events_.clear(); | |
207 } | |
208 // Enable event logging (fast-path). This should be disabled since starting | |
209 // shouldn't be done twice. | |
210 RTC_CHECK_EQ(0, | |
211 rtc::AtomicOps::CompareAndSwap(&g_event_logging_active, 0, 1)); | |
212 | |
213 // Finally start, everything should be set up now. | |
214 logging_thread_.Start(); | |
215 TRACE_EVENT_INSTANT0("webrtc", "EventLogger::Start"); | |
216 } | |
217 | |
218 void Stop() { | |
219 RTC_DCHECK(thread_checker_.CalledOnValidThread()); | |
220 TRACE_EVENT_INSTANT0("webrtc", "EventLogger::Stop"); | |
221 // Try to stop. Abort if we're not currently logging. | |
222 if (rtc::AtomicOps::CompareAndSwap(&g_event_logging_active, 1, 0) == 0) | |
223 return; | |
224 | |
225 // Wake up logging thread to finish writing. | |
226 shutdown_event_.Set(); | |
227 // Join the logging thread. | |
228 logging_thread_.Stop(); | |
229 } | |
230 | |
231 private: | |
232 struct TraceArg { | |
233 const char* name; | |
234 unsigned char type; | |
235 // Copied from webrtc/base/trace_event.h TraceValueUnion. | |
236 union TraceArgValue { | |
237 bool as_bool; | |
238 unsigned long long as_uint; | |
239 long long as_int; | |
240 double as_double; | |
241 const void* as_pointer; | |
242 const char* as_string; | |
243 } value; | |
244 | |
245 // Assert that the size of the union is equal to the size of the as_uint | |
246 // field since we are assigning to arbitrary types using it. | |
247 static_assert(sizeof(TraceArgValue) == sizeof(unsigned long long), | |
248 "Size of TraceArg value union is not equal to the size of " | |
249 "the uint field of that union."); | |
250 }; | |
251 | |
252 struct TraceEvent { | |
253 const char* name; | |
254 const unsigned char* category_enabled; | |
255 char phase; | |
256 std::vector<TraceArg> args; | |
257 uint64_t timestamp; | |
258 int pid; | |
259 rtc::PlatformThreadId tid; | |
260 }; | |
261 | |
262 static std::string TraceArgValueAsString(TraceArg arg) { | |
263 std::string output; | |
264 | |
265 if (arg.type == TRACE_VALUE_TYPE_STRING || | |
266 arg.type == TRACE_VALUE_TYPE_COPY_STRING) { | |
267 // Space for every character to be an espaced character + two for | |
268 // quatation marks. | |
269 output.reserve(strlen(arg.value.as_string) * 2 + 2); | |
270 output += '\"'; | |
271 const char* c = arg.value.as_string; | |
272 do { | |
273 if (*c == '"' || *c == '\\') { | |
274 output += '\\'; | |
275 output += *c; | |
276 } else { | |
277 output += *c; | |
278 } | |
279 } while (*++c); | |
280 output += '\"'; | |
281 } else { | |
282 output.resize(kTraceArgBufferLength); | |
283 size_t print_length = 0; | |
284 switch (arg.type) { | |
285 case TRACE_VALUE_TYPE_BOOL: | |
286 if (arg.value.as_bool) { | |
287 strcpy(&output[0], "true"); | |
288 print_length = 4; | |
289 } else { | |
290 strcpy(&output[0], "false"); | |
291 print_length = 5; | |
292 } | |
293 break; | |
294 case TRACE_VALUE_TYPE_UINT: | |
295 print_length = sprintfn(&output[0], kTraceArgBufferLength, "%llu", | |
296 arg.value.as_uint); | |
297 break; | |
298 case TRACE_VALUE_TYPE_INT: | |
299 print_length = sprintfn(&output[0], kTraceArgBufferLength, "%lld", | |
300 arg.value.as_int); | |
301 break; | |
302 case TRACE_VALUE_TYPE_DOUBLE: | |
303 print_length = sprintfn(&output[0], kTraceArgBufferLength, "%f", | |
304 arg.value.as_double); | |
305 break; | |
306 case TRACE_VALUE_TYPE_POINTER: | |
307 print_length = sprintfn(&output[0], kTraceArgBufferLength, "\"%p\"", | |
308 arg.value.as_pointer); | |
309 break; | |
310 } | |
311 size_t output_length = print_length < kTraceArgBufferLength | |
312 ? print_length | |
313 : kTraceArgBufferLength - 1; | |
314 // This will hopefully be very close to nop. On most implementations, it | |
315 // just writes null byte and sets the length field of the string. | |
316 output.resize(output_length); | |
317 } | |
318 | |
319 return output; | |
320 } | |
321 | |
322 rtc::CriticalSection crit_; | |
323 std::vector<TraceEvent> trace_events_ GUARDED_BY(crit_); | |
324 rtc::PlatformThread logging_thread_; | |
325 rtc::Event shutdown_event_; | |
326 rtc::ThreadChecker thread_checker_; | |
327 FILE* output_file_ = nullptr; | |
328 bool output_file_owned_ = false; | |
329 }; | |
330 | |
331 static void EventTracingThreadFunc(void* params) { | |
332 static_cast<EventLogger*>(params)->Log(); | |
333 } | |
334 | |
335 static EventLogger* volatile g_event_logger = nullptr; | |
336 static const char* const kDisabledTracePrefix = TRACE_DISABLED_BY_DEFAULT(""); | |
337 const unsigned char* InternalGetCategoryEnabled(const char* name) { | |
338 const char* prefix_ptr = &kDisabledTracePrefix[0]; | |
339 const char* name_ptr = name; | |
340 // Check whether name contains the default-disabled prefix. | |
341 while (*prefix_ptr == *name_ptr && *prefix_ptr != '\0') { | |
342 ++prefix_ptr; | |
343 ++name_ptr; | |
344 } | |
345 return reinterpret_cast<const unsigned char*>(*prefix_ptr == '\0' ? "" | |
346 : name); | |
347 } | |
348 | |
349 void InternalAddTraceEvent(char phase, | |
350 const unsigned char* category_enabled, | |
351 const char* name, | |
352 unsigned long long id, | |
353 int num_args, | |
354 const char** arg_names, | |
355 const unsigned char* arg_types, | |
356 const unsigned long long* arg_values, | |
357 unsigned char flags) { | |
358 // Fast path for when event tracing is inactive. | |
359 if (rtc::AtomicOps::AcquireLoad(&g_event_logging_active) == 0) | |
360 return; | |
361 | |
362 g_event_logger->AddTraceEvent(name, category_enabled, phase, num_args, | |
363 arg_names, arg_types, arg_values, | |
364 rtc::TimeMicros(), 1, rtc::CurrentThreadId()); | |
365 } | |
366 | |
367 } // namespace | |
368 | |
369 void SetupInternalTracer() { | |
370 RTC_CHECK(rtc::AtomicOps::CompareAndSwapPtr( | |
371 &g_event_logger, static_cast<EventLogger*>(nullptr), | |
372 new EventLogger()) == nullptr); | |
373 webrtc::SetupEventTracer(InternalGetCategoryEnabled, InternalAddTraceEvent); | |
374 } | |
375 | |
376 void StartInternalCaptureToFile(FILE* file) { | |
377 g_event_logger->Start(file, false); | |
378 } | |
379 | |
380 bool StartInternalCapture(const char* filename) { | |
381 FILE* file = fopen(filename, "w"); | |
382 if (!file) { | |
383 LOG(LS_ERROR) << "Failed to open trace file '" << filename | |
384 << "' for writing."; | |
385 return false; | |
386 } | |
387 g_event_logger->Start(file, true); | |
388 return true; | |
389 } | |
390 | |
391 void StopInternalCapture() { | |
392 g_event_logger->Stop(); | |
393 } | |
394 | |
395 void ShutdownInternalTracer() { | |
396 StopInternalCapture(); | |
397 EventLogger* old_logger = rtc::AtomicOps::AcquireLoadPtr(&g_event_logger); | |
398 RTC_DCHECK(old_logger); | |
399 RTC_CHECK(rtc::AtomicOps::CompareAndSwapPtr( | |
400 &g_event_logger, old_logger, | |
401 static_cast<EventLogger*>(nullptr)) == old_logger); | |
402 delete old_logger; | |
403 webrtc::SetupEventTracer(nullptr, nullptr); | |
404 } | |
405 | |
406 } // namespace tracing | |
407 } // namespace rtc | |
OLD | NEW |