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1 // Copyright 2015 The Chromium Authors. All rights reserved. | 1 // Copyright 2015 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "base/profiler/stack_sampling_profiler.h" | 5 #include "base/profiler/stack_sampling_profiler.h" |
6 | 6 |
7 #include <algorithm> | 7 #include <algorithm> |
8 #include <map> | |
8 #include <utility> | 9 #include <utility> |
9 | 10 |
11 #include "base/atomic_sequence_num.h" | |
12 #include "base/atomicops.h" | |
10 #include "base/bind.h" | 13 #include "base/bind.h" |
11 #include "base/bind_helpers.h" | 14 #include "base/bind_helpers.h" |
12 #include "base/callback.h" | 15 #include "base/callback.h" |
13 #include "base/lazy_instance.h" | 16 #include "base/lazy_instance.h" |
14 #include "base/location.h" | 17 #include "base/location.h" |
15 #include "base/macros.h" | 18 #include "base/macros.h" |
19 #include "base/memory/ptr_util.h" | |
20 #include "base/memory/singleton.h" | |
16 #include "base/profiler/native_stack_sampler.h" | 21 #include "base/profiler/native_stack_sampler.h" |
17 #include "base/synchronization/lock.h" | 22 #include "base/synchronization/lock.h" |
23 #include "base/threading/thread.h" | |
24 #include "base/threading/thread_restrictions.h" | |
18 #include "base/threading/thread_task_runner_handle.h" | 25 #include "base/threading/thread_task_runner_handle.h" |
19 #include "base/timer/elapsed_timer.h" | 26 #include "base/timer/elapsed_timer.h" |
20 | 27 |
21 namespace base { | 28 namespace base { |
22 | 29 |
23 namespace { | 30 namespace { |
24 | 31 |
25 // Used to ensure only one profiler is running at a time. | 32 const int NO_ID = -1; |
26 LazyInstance<Lock>::Leaky concurrent_profiling_lock = LAZY_INSTANCE_INITIALIZER; | |
27 | |
28 // AsyncRunner ---------------------------------------------------------------- | |
29 | |
30 // Helper class to allow a profiler to be run completely asynchronously from the | |
31 // initiator, without being concerned with the profiler's lifetime. | |
32 class AsyncRunner { | |
33 public: | |
34 // Sets up a profiler and arranges for it to be deleted on its completed | |
35 // callback. | |
36 static void Run(PlatformThreadId thread_id, | |
37 const StackSamplingProfiler::SamplingParams& params, | |
38 const StackSamplingProfiler::CompletedCallback& callback); | |
39 | |
40 private: | |
41 AsyncRunner(); | |
42 | |
43 // Runs the callback and deletes the AsyncRunner instance. |profiles| is not | |
44 // const& because it must be passed with std::move. | |
45 static void RunCallbackAndDeleteInstance( | |
46 std::unique_ptr<AsyncRunner> object_to_be_deleted, | |
47 const StackSamplingProfiler::CompletedCallback& callback, | |
48 scoped_refptr<SingleThreadTaskRunner> task_runner, | |
49 StackSamplingProfiler::CallStackProfiles profiles); | |
50 | |
51 std::unique_ptr<StackSamplingProfiler> profiler_; | |
52 | |
53 DISALLOW_COPY_AND_ASSIGN(AsyncRunner); | |
54 }; | |
55 | |
56 // static | |
57 void AsyncRunner::Run( | |
58 PlatformThreadId thread_id, | |
59 const StackSamplingProfiler::SamplingParams& params, | |
60 const StackSamplingProfiler::CompletedCallback &callback) { | |
61 std::unique_ptr<AsyncRunner> runner(new AsyncRunner); | |
62 AsyncRunner* temp_ptr = runner.get(); | |
63 temp_ptr->profiler_.reset( | |
64 new StackSamplingProfiler(thread_id, params, | |
65 Bind(&AsyncRunner::RunCallbackAndDeleteInstance, | |
66 Passed(&runner), callback, | |
67 ThreadTaskRunnerHandle::Get()))); | |
68 // The callback won't be called until after Start(), so temp_ptr will still | |
69 // be valid here. | |
70 temp_ptr->profiler_->Start(); | |
71 } | |
72 | |
73 AsyncRunner::AsyncRunner() {} | |
74 | |
75 void AsyncRunner::RunCallbackAndDeleteInstance( | |
76 std::unique_ptr<AsyncRunner> object_to_be_deleted, | |
77 const StackSamplingProfiler::CompletedCallback& callback, | |
78 scoped_refptr<SingleThreadTaskRunner> task_runner, | |
79 StackSamplingProfiler::CallStackProfiles profiles) { | |
80 callback.Run(std::move(profiles)); | |
81 // Delete the instance on the original calling thread. | |
82 task_runner->DeleteSoon(FROM_HERE, object_to_be_deleted.release()); | |
83 } | |
84 | 33 |
85 void ChangeAtomicFlags(subtle::Atomic32* flags, | 34 void ChangeAtomicFlags(subtle::Atomic32* flags, |
86 subtle::Atomic32 set, | 35 subtle::Atomic32 set, |
87 subtle::Atomic32 clear) { | 36 subtle::Atomic32 clear) { |
88 DCHECK(set != 0 || clear != 0); | 37 DCHECK(set != 0 || clear != 0); |
89 DCHECK_EQ(0, set & clear); | 38 DCHECK_EQ(0, set & clear); |
90 | 39 |
91 subtle::Atomic32 bits = subtle::NoBarrier_Load(flags); | 40 subtle::Atomic32 bits = subtle::NoBarrier_Load(flags); |
92 while (true) { | 41 while (true) { |
93 subtle::Atomic32 existing = | 42 subtle::Atomic32 existing = |
(...skipping 59 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading... | |
153 StackSamplingProfiler::CallStackProfile | 102 StackSamplingProfiler::CallStackProfile |
154 StackSamplingProfiler::CallStackProfile::CopyForTesting() const { | 103 StackSamplingProfiler::CallStackProfile::CopyForTesting() const { |
155 return CallStackProfile(*this); | 104 return CallStackProfile(*this); |
156 } | 105 } |
157 | 106 |
158 StackSamplingProfiler::CallStackProfile::CallStackProfile( | 107 StackSamplingProfiler::CallStackProfile::CallStackProfile( |
159 const CallStackProfile& other) = default; | 108 const CallStackProfile& other) = default; |
160 | 109 |
161 // StackSamplingProfiler::SamplingThread -------------------------------------- | 110 // StackSamplingProfiler::SamplingThread -------------------------------------- |
162 | 111 |
163 StackSamplingProfiler::SamplingThread::SamplingThread( | 112 class StackSamplingProfiler::SamplingThread : public Thread { |
164 std::unique_ptr<NativeStackSampler> native_sampler, | 113 public: |
165 const SamplingParams& params, | 114 class TestAPI { |
166 const CompletedCallback& completed_callback) | 115 public: |
167 : native_sampler_(std::move(native_sampler)), | 116 // Sets the number of ms to wait after becoming idle before shutting down. |
168 params_(params), | 117 // Set to zero to disable. |
169 stop_event_(WaitableEvent::ResetPolicy::AUTOMATIC, | 118 static void SetIdleShutdownTime(int shutdown_ms); |
170 WaitableEvent::InitialState::NOT_SIGNALED), | 119 |
171 completed_callback_(completed_callback) {} | 120 // Begins an idle shutdown as if the idle-timer had expired. |
172 | 121 static void ShutdownIfIdle(); |
173 StackSamplingProfiler::SamplingThread::~SamplingThread() {} | 122 }; |
174 | 123 |
175 void StackSamplingProfiler::SamplingThread::ThreadMain() { | 124 struct CollectionContext { |
176 PlatformThread::SetName("Chrome_SamplingProfilerThread"); | 125 CollectionContext(PlatformThreadId target, |
177 | 126 const SamplingParams& params, |
178 // For now, just ignore any requests to profile while another profiler is | 127 const CompletedCallback& callback, |
179 // working. | 128 WaitableEvent* finished, |
180 if (!concurrent_profiling_lock.Get().Try()) | 129 std::unique_ptr<NativeStackSampler> sampler) |
181 return; | 130 : collection_id(next_collection_id_.GetNext()), |
182 | 131 target(target), |
183 CallStackProfiles profiles; | 132 params(params), |
184 CollectProfiles(&profiles); | 133 callback(callback), |
185 concurrent_profiling_lock.Get().Release(); | 134 finished(finished), |
186 completed_callback_.Run(std::move(profiles)); | 135 native_sampler(std::move(sampler)) {} |
187 } | 136 ~CollectionContext() {} |
188 | 137 |
189 // Depending on how long the sampling takes and the length of the sampling | 138 // An identifier for this collection, used to uniquely identify it to |
190 // interval, a burst of samples could take arbitrarily longer than | 139 // outside interests. |
191 // samples_per_burst * sampling_interval. In this case, we (somewhat | 140 const int collection_id; |
192 // arbitrarily) honor the number of samples requested rather than strictly | 141 |
193 // adhering to the sampling intervals. Once we have established users for the | 142 const PlatformThreadId target; // ID of The thread being sampled. |
194 // StackSamplingProfiler and the collected data to judge, we may go the other | 143 const SamplingParams params; // Information about how to sample. |
195 // way or make this behavior configurable. | 144 const CompletedCallback callback; // Callback made when sampling complete. |
196 void StackSamplingProfiler::SamplingThread::CollectProfile( | 145 WaitableEvent* const finished; // Signaled when all sampling complete. |
197 CallStackProfile* profile, | 146 |
198 TimeDelta* elapsed_time, | 147 // Platform-specific module that does the actual sampling. |
199 bool* was_stopped) { | 148 std::unique_ptr<NativeStackSampler> native_sampler; |
200 ElapsedTimer profile_timer; | 149 |
201 native_sampler_->ProfileRecordingStarting(&profile->modules); | 150 // The absolute time for the next sample. |
202 profile->sampling_period = params_.sampling_interval; | 151 Time next_sample_time; |
203 *was_stopped = false; | 152 |
204 TimeDelta previous_elapsed_sample_time; | 153 // The time that a profile was started, for calculating the total duration. |
205 for (int i = 0; i < params_.samples_per_burst; ++i) { | 154 Time profile_start_time; |
206 if (i != 0) { | 155 |
207 // Always wait, even if for 0 seconds, so we can observe a signal on | 156 // Counters that indicate the current position along the acquisition. |
208 // stop_event_. | 157 int burst = 0; |
209 if (stop_event_.TimedWait( | 158 int sample = 0; |
210 std::max(params_.sampling_interval - previous_elapsed_sample_time, | 159 |
211 TimeDelta()))) { | 160 // The collected stack samples. The active profile is always at the back(). |
212 *was_stopped = true; | 161 CallStackProfiles profiles; |
213 break; | 162 |
214 } | 163 private: |
215 } | 164 static StaticAtomicSequenceNumber next_collection_id_; |
216 ElapsedTimer sample_timer; | 165 }; |
217 profile->samples.push_back(Sample()); | 166 |
218 native_sampler_->RecordStackSample(&profile->samples.back()); | 167 // Gets the single instance of this class. |
219 previous_elapsed_sample_time = sample_timer.Elapsed(); | 168 static SamplingThread* GetInstance(); |
220 } | 169 |
221 | 170 // Starts the thread. |
222 *elapsed_time = profile_timer.Elapsed(); | 171 void Start(); |
223 profile->profile_duration = *elapsed_time; | 172 |
224 native_sampler_->ProfileRecordingStopped(); | 173 // Adds a new CollectionContext to the thread. This can be called externally |
225 } | 174 // from any thread. This returns an ID that can later be used to stop |
226 | 175 // the sampling. |
227 // In an analogous manner to CollectProfile() and samples exceeding the expected | 176 int Add(std::unique_ptr<CollectionContext> collection); |
228 // total sampling time, bursts may also exceed the burst_interval. We adopt the | 177 |
229 // same wait-and-see approach here. | 178 // Removes an active collection based on its ID, forcing it to run its |
230 void StackSamplingProfiler::SamplingThread::CollectProfiles( | 179 // callback if any data has been collected. This can be called externally |
231 CallStackProfiles* profiles) { | 180 // from any thread. |
232 if (stop_event_.TimedWait(params_.initial_delay)) | 181 void Remove(int id); |
233 return; | 182 |
234 | 183 private: |
235 TimeDelta previous_elapsed_profile_time; | 184 friend class TestAPI; |
236 for (int i = 0; i < params_.bursts; ++i) { | 185 friend struct DefaultSingletonTraits<SamplingThread>; |
237 if (i != 0) { | 186 |
238 // Always wait, even if for 0 seconds, so we can observe a signal on | 187 enum ThreadExecutionState { |
Mike Wittman
2017/02/23 18:26:52
This needs substantial comments explaining the lif
bcwhite
2017/02/24 20:39:25
Done.
| |
239 // stop_event_. | 188 NOT_STARTED, |
240 if (stop_event_.TimedWait( | 189 RUNNING, |
241 std::max(params_.burst_interval - previous_elapsed_profile_time, | 190 EXITING, |
242 TimeDelta()))) | 191 }; |
243 return; | 192 |
244 } | 193 SamplingThread(); |
245 | 194 ~SamplingThread() override; |
246 CallStackProfile profile; | 195 |
247 bool was_stopped = false; | 196 // Get task runner that is usable from the outside. |
248 CollectProfile(&profile, &previous_elapsed_profile_time, &was_stopped); | 197 scoped_refptr<SingleThreadTaskRunner> GetOrCreateTaskRunner(); |
249 if (!profile.samples.empty()) | 198 scoped_refptr<SingleThreadTaskRunner> GetTaskRunner( |
250 profiles->push_back(std::move(profile)); | 199 ThreadExecutionState* out_state); |
251 | 200 |
252 if (was_stopped) | 201 // Get task runner that is usable from the sampling thread itself. |
253 return; | 202 scoped_refptr<SingleThreadTaskRunner> GetTaskRunnerOnSamplingThread(); |
254 } | 203 |
255 } | 204 // Finishes a collection and reports collected data via callback. |
256 | 205 void FinishCollection(CollectionContext* collection); |
257 void StackSamplingProfiler::SamplingThread::Stop() { | 206 |
258 stop_event_.Signal(); | 207 // Records a single sample of a collection. |
208 void RecordSample(CollectionContext* collection); | |
209 | |
210 // Check if the sampling thread is idle and begin a shutdown if so. | |
211 void ScheduleShutdownIfIdle(); | |
212 | |
213 // These methods are tasks that get posted to the internal message queue. | |
214 void AddCollectionTask(std::unique_ptr<CollectionContext> collection); | |
215 void RemoveCollectionTask(int id); | |
216 void PerformCollectionTask(int id); | |
217 void ShutdownTask(int add_events); | |
218 | |
219 // Updates the |next_sample_time| time based on configured parameters. | |
220 bool UpdateNextSampleTime(CollectionContext* collection); | |
221 | |
222 // Thread: | |
223 void CleanUp() override; | |
224 | |
225 // The task-runner for the sampling thread and some information about it. | |
226 // This must always be accessed while holding the lock. The saved task-runner | |
227 // can be freely used by any calling thread. | |
228 Lock task_runner_lock_; | |
229 scoped_refptr<SingleThreadTaskRunner> task_runner_; | |
230 ThreadExecutionState task_runner_thread_state_ = NOT_STARTED; | |
231 TimeDelta task_runner_idle_shutdown_time_ = TimeDelta::FromSeconds(60); | |
232 | |
233 // A counter that notes adds of new collection requests. It is incremented | |
234 // when changes occur so that delayed shutdown tasks are able to detect if | |
235 // samething new has happened while it was waiting. Like all |task_runner_*| | |
236 // vars, this must be accessed while holding |task_runner_lock_|. | |
237 int task_runner_add_events_ = 0; | |
238 | |
239 // A map of IDs to collection contexts. Because this class is a singleton | |
240 // that is never destroyed, context objects will never be destructed except | |
241 // by explicit action. Thus, it's acceptable to pass unretained pointers | |
242 // to these objects when posting tasks. | |
243 std::map<int, std::unique_ptr<CollectionContext>> active_collections_; | |
244 | |
245 DISALLOW_COPY_AND_ASSIGN(SamplingThread); | |
246 }; | |
247 | |
248 void StackSamplingProfiler::SamplingThread::TestAPI::SetIdleShutdownTime( | |
249 int shutdown_ms) { | |
250 SamplingThread* sampler = SamplingThread::GetInstance(); | |
251 DCHECK(sampler); | |
252 | |
253 AutoLock lock(sampler->task_runner_lock_); | |
254 sampler->task_runner_idle_shutdown_time_ = | |
255 TimeDelta::FromMilliseconds(shutdown_ms); | |
256 } | |
257 | |
258 void StackSamplingProfiler::SamplingThread::TestAPI::ShutdownIfIdle() { | |
259 SamplingThread* sampler = SamplingThread::GetInstance(); | |
260 DCHECK(sampler); | |
261 | |
262 ThreadExecutionState state; | |
263 scoped_refptr<SingleThreadTaskRunner> task_runner = | |
264 sampler->GetTaskRunner(&state); | |
265 if (state != RUNNING) | |
Mike Wittman
2017/02/23 18:26:52
DCHECK_EQ(RUNNING, state)
unless this is called i
bcwhite
2017/02/24 20:39:25
Done.
| |
266 return; | |
267 DCHECK(task_runner); | |
268 | |
269 int add_events; | |
270 { | |
271 AutoLock lock(sampler->task_runner_lock_); | |
272 add_events = sampler->task_runner_add_events_; | |
273 } | |
274 | |
275 // ShutdownTask will check if the thread is idle and skip the shutdown if not. | |
276 task_runner->PostTask(FROM_HERE, Bind(&SamplingThread::ShutdownTask, | |
277 Unretained(sampler), add_events)); | |
278 } | |
279 | |
280 StaticAtomicSequenceNumber StackSamplingProfiler::SamplingThread:: | |
281 CollectionContext::next_collection_id_; | |
282 | |
283 StackSamplingProfiler::SamplingThread::SamplingThread() | |
284 : Thread("Chrome_SamplingProfilerThread") {} | |
285 | |
286 StackSamplingProfiler::SamplingThread::~SamplingThread() { | |
287 Stop(); | |
288 } | |
289 | |
290 StackSamplingProfiler::SamplingThread* | |
291 StackSamplingProfiler::SamplingThread::GetInstance() { | |
292 return Singleton<SamplingThread, LeakySingletonTraits<SamplingThread>>::get(); | |
293 } | |
294 | |
295 void StackSamplingProfiler::SamplingThread::Start() { | |
296 Thread::Options options; | |
297 // Use a higher priority for a more accurate sampling interval. | |
298 options.priority = ThreadPriority::DISPLAY; | |
299 Thread::StartWithOptions(options); | |
300 } | |
301 | |
302 int StackSamplingProfiler::SamplingThread::Add( | |
303 std::unique_ptr<CollectionContext> collection) { | |
304 int id = collection->collection_id; | |
305 scoped_refptr<SingleThreadTaskRunner> task_runner = GetOrCreateTaskRunner(); | |
306 | |
307 task_runner->PostTask(FROM_HERE, Bind(&SamplingThread::AddCollectionTask, | |
308 Unretained(this), Passed(&collection))); | |
309 | |
310 return id; | |
311 } | |
312 | |
313 void StackSamplingProfiler::SamplingThread::Remove(int id) { | |
314 ThreadExecutionState state; | |
315 scoped_refptr<SingleThreadTaskRunner> task_runner = GetTaskRunner(&state); | |
316 if (state != RUNNING) | |
Mike Wittman
2017/02/23 18:26:52
DCHECK_NE(NOT_STARTED, state) before this
bcwhite
2017/02/24 20:39:25
It could legitimately be in that state if the the
Mike Wittman
2017/02/27 23:27:34
Won't it be in the EXITING state in that case?
bcwhite
2017/03/13 18:50:17
Yes. Originally I had planned for the thread to g
| |
317 return; | |
318 DCHECK(task_runner); | |
319 | |
320 // This can fail if the thread were to exit between acquisition of the task | |
321 // runner above and the call below. In that case, however, everything has | |
322 // stopped so there's no need to try to stop it. | |
323 task_runner->PostTask(FROM_HERE, Bind(&SamplingThread::RemoveCollectionTask, | |
324 Unretained(this), id)); | |
325 } | |
326 | |
327 scoped_refptr<SingleThreadTaskRunner> | |
328 StackSamplingProfiler::SamplingThread::GetOrCreateTaskRunner() { | |
329 AutoLock lock(task_runner_lock_); | |
330 ++task_runner_add_events_; | |
331 if (task_runner_thread_state_ != RUNNING) { | |
Mike Wittman
2017/02/23 18:26:52
I think this code would be easier to follow struct
bcwhite
2017/02/24 20:39:25
Done.
| |
332 // If this is not the first time the sampling thread has been launched, the | |
333 // previous instance has only been partially cleaned up. It is necessary | |
334 // to call Stop() before Start(). This is safe even the thread has never | |
335 // been started. | |
336 Stop(); | |
337 // The thread is not running. Start it and get associated runner. The task- | |
338 // runner has to be saved for future use because though it can be used from | |
339 // any thread, it can be acquired via task_runner() only on the created | |
340 // thread and the thread that creates it (i.e. this thread). | |
341 Start(); | |
342 task_runner_thread_state_ = RUNNING; | |
343 task_runner_ = Thread::task_runner(); | |
344 // Detach the sampling thread from the "sequence" (i.e. thread) that | |
345 // started it so that it can be self-managed or stopped by another thread. | |
346 DetachFromSequence(); | |
347 } else { | |
348 DCHECK(task_runner_); | |
349 // This shouldn't be called from the sampling thread as it's inefficient. | |
350 // Use GetTaskRunnerOnSamplingThread() instead. | |
351 DCHECK_NE(GetThreadId(), PlatformThread::CurrentId()); | |
352 } | |
353 | |
354 return task_runner_; | |
355 } | |
356 | |
357 scoped_refptr<SingleThreadTaskRunner> | |
358 StackSamplingProfiler::SamplingThread::GetTaskRunner( | |
359 ThreadExecutionState* out_state) { | |
360 AutoLock lock(task_runner_lock_); | |
361 if (out_state) | |
362 *out_state = task_runner_thread_state_; | |
363 if (task_runner_thread_state_ != RUNNING) | |
Mike Wittman
2017/02/23 18:26:52
This would be better as a DCHECK:
DCHECK(task_runn
bcwhite
2017/02/24 20:39:25
It needs to handle not-RUNNING by exiting early or
Mike Wittman
2017/02/27 23:27:34
How about putting the DCHECKS in a conditional the
bcwhite
2017/03/13 18:50:17
Done.
| |
364 return nullptr; | |
365 | |
366 // This shouldn't be called from the sampling thread as it's inefficient. | |
367 // Use GetTaskRunnerOnSamplingThread() instead. | |
368 DCHECK_NE(GetThreadId(), PlatformThread::CurrentId()); | |
369 | |
370 return task_runner_; | |
371 } | |
372 | |
373 scoped_refptr<SingleThreadTaskRunner> | |
374 StackSamplingProfiler::SamplingThread::GetTaskRunnerOnSamplingThread() { | |
375 // This should be called only from the sampling thread as it has limited | |
376 // accessibility. | |
377 DCHECK_EQ(GetThreadId(), PlatformThread::CurrentId()); | |
378 | |
379 return Thread::task_runner(); | |
380 } | |
381 | |
382 void StackSamplingProfiler::SamplingThread::FinishCollection( | |
383 CollectionContext* collection) { | |
384 // If there is no duration for the final profile (because it was stopped), | |
385 // calculate it now. | |
386 if (!collection->profiles.empty() && | |
387 collection->profiles.back().profile_duration == TimeDelta()) { | |
388 collection->profiles.back().profile_duration = | |
389 Time::Now() - collection->profile_start_time; | |
390 } | |
391 | |
392 // Run the associated callback, passing the collected profiles. It's okay to | |
393 // move them because this collection is about to be deleted. | |
394 collection->callback.Run(std::move(collection->profiles)); | |
395 | |
396 // Signal that this collection is finished. | |
397 collection->finished->Signal(); | |
398 | |
399 // Remove this collection from the map of known ones. This must be done | |
400 // last as the |collection| parameter is invalid after this point. | |
401 size_t count = active_collections_.erase(collection->collection_id); | |
402 DCHECK_EQ(1U, count); | |
403 } | |
404 | |
405 void StackSamplingProfiler::SamplingThread::RecordSample( | |
406 CollectionContext* collection) { | |
407 DCHECK(collection->native_sampler); | |
408 | |
409 // If this is the first sample of a burst, a new Profile needs to be created | |
410 // and filled. | |
411 if (collection->sample == 0) { | |
412 collection->profiles.push_back(CallStackProfile()); | |
413 CallStackProfile& profile = collection->profiles.back(); | |
414 profile.sampling_period = collection->params.sampling_interval; | |
415 collection->profile_start_time = Time::Now(); | |
416 collection->native_sampler->ProfileRecordingStarting(&profile.modules); | |
417 } | |
418 | |
419 // The currently active profile being captured. | |
420 CallStackProfile& profile = collection->profiles.back(); | |
421 | |
422 // Record a single sample. | |
423 profile.samples.push_back(Sample()); | |
424 collection->native_sampler->RecordStackSample(&profile.samples.back()); | |
425 | |
426 // If this is the last sample of a burst, record the total time. | |
427 if (collection->sample == collection->params.samples_per_burst - 1) { | |
428 profile.profile_duration = Time::Now() - collection->profile_start_time; | |
429 collection->native_sampler->ProfileRecordingStopped(); | |
430 } | |
431 } | |
432 | |
433 void StackSamplingProfiler::SamplingThread::ScheduleShutdownIfIdle() { | |
434 if (!active_collections_.empty()) | |
435 return; | |
436 | |
437 int add_events; | |
438 TimeDelta delay; | |
439 { | |
440 AutoLock lock(task_runner_lock_); | |
441 add_events = task_runner_add_events_; | |
442 delay = task_runner_idle_shutdown_time_; | |
443 } | |
444 | |
445 if (!delay.is_zero()) { | |
446 GetTaskRunnerOnSamplingThread()->PostDelayedTask( | |
447 FROM_HERE, | |
448 Bind(&SamplingThread::ShutdownTask, Unretained(this), add_events), | |
449 delay); | |
450 } | |
451 } | |
452 | |
453 void StackSamplingProfiler::SamplingThread::AddCollectionTask( | |
454 std::unique_ptr<CollectionContext> collection) { | |
455 const int collection_id = collection->collection_id; | |
456 const TimeDelta initial_delay = collection->params.initial_delay; | |
457 | |
458 active_collections_.insert( | |
459 std::make_pair(collection_id, std::move(collection))); | |
460 | |
461 GetTaskRunnerOnSamplingThread()->PostDelayedTask( | |
462 FROM_HERE, Bind(&SamplingThread::PerformCollectionTask, Unretained(this), | |
463 collection_id), | |
464 initial_delay); | |
465 | |
466 // Another increment of "create requests" serves to invalidate any pending | |
467 // shutdown tasks that may have been initiated between the Add() and this | |
468 // task running. | |
469 { | |
470 AutoLock lock(task_runner_lock_); | |
471 ++task_runner_add_events_; | |
472 } | |
473 } | |
474 | |
475 void StackSamplingProfiler::SamplingThread::RemoveCollectionTask(int id) { | |
476 auto found = active_collections_.find(id); | |
477 if (found == active_collections_.end()) | |
478 return; | |
479 | |
480 FinishCollection(found->second.get()); | |
481 ScheduleShutdownIfIdle(); | |
482 } | |
483 | |
484 void StackSamplingProfiler::SamplingThread::PerformCollectionTask(int id) { | |
485 auto found = active_collections_.find(id); | |
486 | |
487 // The task won't be found if it has been stopped. | |
488 if (found == active_collections_.end()) | |
489 return; | |
490 | |
491 CollectionContext* collection = found->second.get(); | |
492 | |
493 // Handle first-run with no "next time". | |
494 if (collection->next_sample_time == Time()) | |
495 collection->next_sample_time = Time::Now(); | |
496 | |
497 // Do the collection of a single sample. | |
498 RecordSample(collection); | |
499 | |
500 // Update the time of the next sample recording. | |
501 if (UpdateNextSampleTime(collection)) { | |
502 bool success = GetTaskRunnerOnSamplingThread()->PostDelayedTask( | |
503 FROM_HERE, | |
504 Bind(&SamplingThread::PerformCollectionTask, Unretained(this), id), | |
505 std::max(collection->next_sample_time - Time::Now(), TimeDelta())); | |
506 DCHECK(success); | |
507 } else { | |
508 // All capturing has completed so finish the collection. Let object expire. | |
509 // The |collection| variable will be invalid after this call. | |
510 FinishCollection(collection); | |
511 ScheduleShutdownIfIdle(); | |
512 } | |
513 } | |
514 | |
515 void StackSamplingProfiler::SamplingThread::ShutdownTask(int add_events) { | |
516 // Holding this lock ensures that any attempt to start another job will | |
517 // get postponed until task_runner_ is cleared, thus eliminating the race. | |
518 AutoLock lock(task_runner_lock_); | |
519 | |
520 // If the current count of creation requests doesn't match the passed count | |
521 // then other tasks have been created since this was posted. Abort shutdown. | |
522 if (task_runner_add_events_ != add_events) | |
523 return; | |
524 | |
525 // There can be no new AddCollectionTasks at this point because creating | |
526 // those always increments "create requests". There may be other requests, | |
527 // like Remove, but it's okay to schedule the thread to stop once they've | |
528 // been executed (i.e. "soon"). | |
529 StopSoon(); | |
530 | |
531 // StopSoon will have set the owning sequence (again) so it must be detached | |
532 // (again) in order for Stop/Start to be called (again) should more work | |
533 // come in. Holding the |task_runner_lock_| ensures the necessary happens- | |
534 // after with regard to this detach and future Thread API calls. | |
535 DetachFromSequence(); | |
536 | |
537 // Set the thread_state variable so the thread will be restarted when new | |
538 // work comes in. | |
539 task_runner_thread_state_ = EXITING; | |
540 } | |
541 | |
542 bool StackSamplingProfiler::SamplingThread::UpdateNextSampleTime( | |
543 CollectionContext* collection) { | |
544 // This will keep a consistent average interval between samples but will | |
545 // result in constant series of acquisitions, thus nearly locking out the | |
546 // target thread, if the interval is smaller than the time it takes to | |
547 // actually acquire the sample. Anything sampling that quickly is going | |
548 // to be a problem anyway so don't worry about it. | |
549 if (++collection->sample < collection->params.samples_per_burst) { | |
550 collection->next_sample_time += collection->params.sampling_interval; | |
551 return true; | |
552 } | |
553 | |
554 if (++collection->burst < collection->params.bursts) { | |
555 collection->sample = 0; | |
556 collection->next_sample_time += collection->params.burst_interval; | |
557 return true; | |
558 } | |
559 | |
560 return false; | |
561 } | |
562 | |
563 void StackSamplingProfiler::SamplingThread::CleanUp() { | |
564 // There should be no collections remaining when the thread stops. | |
565 DCHECK(active_collections_.empty()); | |
566 | |
567 // Let the parent clean up. | |
568 Thread::CleanUp(); | |
569 | |
570 { | |
571 AutoLock lock(task_runner_lock_); | |
572 task_runner_thread_state_ = NOT_STARTED; | |
Mike Wittman
2017/02/23 18:26:52
I don't think we need or want this. CleanUp is doc
bcwhite
2017/02/24 20:39:25
Done.
| |
573 } | |
259 } | 574 } |
260 | 575 |
261 // StackSamplingProfiler ------------------------------------------------------ | 576 // StackSamplingProfiler ------------------------------------------------------ |
262 | 577 |
578 // static | |
579 bool StackSamplingProfiler::TestAPI::IsSamplingThreadRunning() { | |
580 return SamplingThread::GetInstance()->IsRunning(); | |
581 } | |
582 | |
583 // static | |
584 void StackSamplingProfiler::TestAPI::SetSamplingThreadIdleShutdownTime( | |
585 int shutdown_ms) { | |
586 SamplingThread::TestAPI::SetIdleShutdownTime(shutdown_ms); | |
587 } | |
588 | |
589 // static | |
590 void StackSamplingProfiler::TestAPI::InitiateSamplingThreadIdleShutdown() { | |
591 SamplingThread::TestAPI::ShutdownIfIdle(); | |
592 } | |
593 | |
263 subtle::Atomic32 StackSamplingProfiler::process_milestones_ = 0; | 594 subtle::Atomic32 StackSamplingProfiler::process_milestones_ = 0; |
264 | 595 |
265 StackSamplingProfiler::SamplingParams::SamplingParams() | 596 StackSamplingProfiler::SamplingParams::SamplingParams() |
266 : initial_delay(TimeDelta::FromMilliseconds(0)), | 597 : initial_delay(TimeDelta::FromMilliseconds(0)), |
267 bursts(1), | 598 bursts(1), |
268 burst_interval(TimeDelta::FromMilliseconds(10000)), | 599 burst_interval(TimeDelta::FromMilliseconds(10000)), |
269 samples_per_burst(300), | 600 samples_per_burst(300), |
270 sampling_interval(TimeDelta::FromMilliseconds(100)) { | 601 sampling_interval(TimeDelta::FromMilliseconds(100)) { |
271 } | 602 } |
272 | 603 |
273 StackSamplingProfiler::StackSamplingProfiler( | 604 StackSamplingProfiler::StackSamplingProfiler( |
274 PlatformThreadId thread_id, | |
275 const SamplingParams& params, | 605 const SamplingParams& params, |
276 const CompletedCallback& callback) | 606 const CompletedCallback& callback, |
277 : StackSamplingProfiler(thread_id, params, callback, nullptr) {} | 607 NativeStackSamplerTestDelegate* test_delegate) |
608 : StackSamplingProfiler(base::PlatformThread::CurrentId(), | |
609 params, | |
610 callback, | |
611 test_delegate) {} | |
278 | 612 |
279 StackSamplingProfiler::StackSamplingProfiler( | 613 StackSamplingProfiler::StackSamplingProfiler( |
280 PlatformThreadId thread_id, | 614 PlatformThreadId thread_id, |
281 const SamplingParams& params, | 615 const SamplingParams& params, |
282 const CompletedCallback& callback, | 616 const CompletedCallback& callback, |
283 NativeStackSamplerTestDelegate* test_delegate) | 617 NativeStackSamplerTestDelegate* test_delegate) |
284 : thread_id_(thread_id), params_(params), completed_callback_(callback), | 618 : thread_id_(thread_id), |
285 test_delegate_(test_delegate) { | 619 params_(params), |
286 } | 620 completed_callback_(callback), |
621 finished_event_(WaitableEvent::ResetPolicy::MANUAL, | |
622 WaitableEvent::InitialState::SIGNALED), | |
623 collection_id_(NO_ID), | |
624 test_delegate_(test_delegate) {} | |
287 | 625 |
288 StackSamplingProfiler::~StackSamplingProfiler() { | 626 StackSamplingProfiler::~StackSamplingProfiler() { |
627 // Stop is immediate but asynchronous. There is a non-zero probability that | |
628 // one more sample will be taken after this call returns. | |
289 Stop(); | 629 Stop(); |
290 if (!sampling_thread_handle_.is_null()) | |
291 PlatformThread::Join(sampling_thread_handle_); | |
292 } | |
293 | 630 |
294 // static | 631 // The behavior of sampling a thread that has exited is undefined and could |
295 void StackSamplingProfiler::StartAndRunAsync( | 632 // cause Bad Things(tm) to occur. The safety model provided by this class is |
296 PlatformThreadId thread_id, | 633 // that an instance of this object is expected to live at least as long as |
297 const SamplingParams& params, | 634 // the thread it is sampling. However, because the sampling is performed |
298 const CompletedCallback& callback) { | 635 // asynchronously by the SamplingThread, there is no way to guarantee this |
299 CHECK(ThreadTaskRunnerHandle::Get()); | 636 // is true without waiting for it to signal that it has finished. |
300 AsyncRunner::Run(thread_id, params, callback); | 637 // |
638 // The wait time should, at most, be only as long as it takes to collect one | |
639 // sample (~200us) or none at all if sampling has already completed. | |
640 ThreadRestrictions::ScopedAllowWait allow_wait; | |
641 finished_event_.Wait(); | |
301 } | 642 } |
302 | 643 |
303 void StackSamplingProfiler::Start() { | 644 void StackSamplingProfiler::Start() { |
304 if (completed_callback_.is_null()) | 645 if (completed_callback_.is_null()) |
305 return; | 646 return; |
306 | 647 |
307 std::unique_ptr<NativeStackSampler> native_sampler = | 648 std::unique_ptr<NativeStackSampler> native_sampler = |
308 NativeStackSampler::Create(thread_id_, &RecordAnnotations, | 649 NativeStackSampler::Create(thread_id_, &RecordAnnotations, |
309 test_delegate_); | 650 test_delegate_); |
651 | |
310 if (!native_sampler) | 652 if (!native_sampler) |
311 return; | 653 return; |
312 | 654 |
313 sampling_thread_.reset(new SamplingThread(std::move(native_sampler), params_, | 655 // If the finished-event is not signalled (default state is signalled) then |
314 completed_callback_)); | 656 // profiling has been previously started but has not completed. Wait for it |
315 if (!PlatformThread::Create(0, sampling_thread_.get(), | 657 // to do so and then reset it for this run. |
316 &sampling_thread_handle_)) | 658 if (!finished_event_.IsSignaled()) |
317 sampling_thread_.reset(); | 659 finished_event_.Wait(); |
660 finished_event_.Reset(); | |
661 | |
662 DCHECK_EQ(NO_ID, collection_id_); | |
663 collection_id_ = SamplingThread::GetInstance()->Add( | |
664 MakeUnique<SamplingThread::CollectionContext>( | |
665 thread_id_, params_, completed_callback_, &finished_event_, | |
666 std::move(native_sampler))); | |
667 DCHECK_NE(NO_ID, collection_id_); | |
318 } | 668 } |
319 | 669 |
320 void StackSamplingProfiler::Stop() { | 670 void StackSamplingProfiler::Stop() { |
321 if (sampling_thread_) | 671 if (collection_id_ == NO_ID) { |
322 sampling_thread_->Stop(); | 672 finished_event_.Signal(); |
673 return; | |
674 } | |
675 | |
676 SamplingThread::GetInstance()->Remove(collection_id_); | |
677 collection_id_ = NO_ID; | |
323 } | 678 } |
324 | 679 |
325 // static | 680 // static |
326 void StackSamplingProfiler::SetProcessMilestone(int milestone) { | 681 void StackSamplingProfiler::SetProcessMilestone(int milestone) { |
327 DCHECK_LE(0, milestone); | 682 DCHECK_LE(0, milestone); |
328 DCHECK_GT(static_cast<int>(sizeof(process_milestones_) * 8), milestone); | 683 DCHECK_GT(static_cast<int>(sizeof(process_milestones_) * 8), milestone); |
329 DCHECK_EQ(0, subtle::NoBarrier_Load(&process_milestones_) & (1 << milestone)); | 684 DCHECK_EQ(0, subtle::NoBarrier_Load(&process_milestones_) & (1 << milestone)); |
330 ChangeAtomicFlags(&process_milestones_, 1 << milestone, 0); | 685 ChangeAtomicFlags(&process_milestones_, 1 << milestone, 0); |
331 } | 686 } |
332 | 687 |
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378 } | 733 } |
379 | 734 |
380 bool operator<(const StackSamplingProfiler::Frame &a, | 735 bool operator<(const StackSamplingProfiler::Frame &a, |
381 const StackSamplingProfiler::Frame &b) { | 736 const StackSamplingProfiler::Frame &b) { |
382 return (a.module_index < b.module_index) || | 737 return (a.module_index < b.module_index) || |
383 (a.module_index == b.module_index && | 738 (a.module_index == b.module_index && |
384 a.instruction_pointer < b.instruction_pointer); | 739 a.instruction_pointer < b.instruction_pointer); |
385 } | 740 } |
386 | 741 |
387 } // namespace base | 742 } // namespace base |
OLD | NEW |