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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. | |
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 | |
85 void ChangeAtomicFlags(subtle::Atomic32* flags, | 32 void ChangeAtomicFlags(subtle::Atomic32* flags, |
86 subtle::Atomic32 set, | 33 subtle::Atomic32 set, |
87 subtle::Atomic32 clear) { | 34 subtle::Atomic32 clear) { |
88 DCHECK(set != 0 || clear != 0); | 35 DCHECK(set != 0 || clear != 0); |
89 DCHECK_EQ(0, set & clear); | 36 DCHECK_EQ(0, set & clear); |
90 | 37 |
91 subtle::Atomic32 bits = subtle::NoBarrier_Load(flags); | 38 subtle::Atomic32 bits = subtle::NoBarrier_Load(flags); |
92 while (true) { | 39 while (true) { |
93 subtle::Atomic32 existing = | 40 subtle::Atomic32 existing = |
94 subtle::NoBarrier_CompareAndSwap(flags, bits, (bits | set) & ~clear); | 41 subtle::NoBarrier_CompareAndSwap(flags, bits, (bits | set) & ~clear); |
(...skipping 58 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading... | |
153 StackSamplingProfiler::CallStackProfile | 100 StackSamplingProfiler::CallStackProfile |
154 StackSamplingProfiler::CallStackProfile::CopyForTesting() const { | 101 StackSamplingProfiler::CallStackProfile::CopyForTesting() const { |
155 return CallStackProfile(*this); | 102 return CallStackProfile(*this); |
156 } | 103 } |
157 | 104 |
158 StackSamplingProfiler::CallStackProfile::CallStackProfile( | 105 StackSamplingProfiler::CallStackProfile::CallStackProfile( |
159 const CallStackProfile& other) = default; | 106 const CallStackProfile& other) = default; |
160 | 107 |
161 // StackSamplingProfiler::SamplingThread -------------------------------------- | 108 // StackSamplingProfiler::SamplingThread -------------------------------------- |
162 | 109 |
163 StackSamplingProfiler::SamplingThread::SamplingThread( | 110 class StackSamplingProfiler::SamplingThread : public Thread { |
164 std::unique_ptr<NativeStackSampler> native_sampler, | 111 public: |
165 const SamplingParams& params, | 112 struct CollectionContext { |
166 const CompletedCallback& completed_callback) | 113 CollectionContext(PlatformThreadId target, |
167 : native_sampler_(std::move(native_sampler)), | 114 const SamplingParams& params, |
168 params_(params), | 115 const CompletedCallback& callback, |
169 stop_event_(WaitableEvent::ResetPolicy::AUTOMATIC, | 116 WaitableEvent* finished, |
170 WaitableEvent::InitialState::NOT_SIGNALED), | 117 NativeStackSampler* sampler) |
171 completed_callback_(completed_callback) {} | 118 : collection_id(next_collection_id_.GetNext()), |
172 | 119 target(target), |
173 StackSamplingProfiler::SamplingThread::~SamplingThread() {} | 120 params(params), |
174 | 121 callback(callback), |
175 void StackSamplingProfiler::SamplingThread::ThreadMain() { | 122 finished(finished), |
176 PlatformThread::SetName("Chrome_SamplingProfilerThread"); | 123 native_sampler(sampler) {} |
177 | 124 ~CollectionContext() {} |
178 // For now, just ignore any requests to profile while another profiler is | 125 |
179 // working. | 126 // An identifier for this collection, used to uniquely identify it to |
180 if (!concurrent_profiling_lock.Get().Try()) | 127 // outside interests. |
128 const int collection_id; | |
129 | |
130 const PlatformThreadId target; // ID of The thread being sampled. | |
131 const SamplingParams params; // Information about how to sample. | |
132 const CompletedCallback callback; // Callback made when sampling complete. | |
133 WaitableEvent* const finished; // Signaled when all sampling complete. | |
134 | |
135 // Platform-specific module that does the actual sampling. Ownership stays | |
136 // with the parent StackSamplingProfiler object. | |
137 NativeStackSampler* const native_sampler; | |
138 | |
139 // The absolute time for the next sample. | |
140 Time next_sample_time; | |
141 | |
142 // The time that a profile was started, for calculating the total duration. | |
143 Time profile_start_time; | |
144 | |
145 // Counters that indicate the current position along the acquisition. | |
146 int burst = 0; | |
147 int sample = 0; | |
148 | |
149 // The collected stack samples. The active profile is always at the back(). | |
150 CallStackProfiles profiles; | |
151 | |
152 private: | |
153 static StaticAtomicSequenceNumber next_collection_id_; | |
154 }; | |
155 | |
156 // Gets the single instance of this class. | |
157 static SamplingThread* GetInstance(); | |
158 | |
159 // Starts the thread. | |
160 void Start(); | |
161 | |
162 // Adds a new CollectionContext to the thread. This can be called externally | |
163 // from any thread. This returns an ID that can later be used to stop | |
164 // the sampling. | |
165 int Add(std::unique_ptr<CollectionContext> collection); | |
166 | |
167 // Removes an active collection based on its ID, forcing it to run its | |
168 // callback if any data has been collected. This can be called externally | |
169 // from any thread. | |
170 void Remove(int id); | |
171 | |
172 // Begins an idle shutdown as if the idle-timer had expired. | |
173 void ShutdownIfIdle(); | |
174 | |
175 // Sets the number of ms to wait after becoming idle before shutting down. | |
176 // Set to zero to disable. | |
177 void SetIdleShutdownTime(int shutdown_ms); | |
178 | |
179 private: | |
180 SamplingThread(); | |
181 ~SamplingThread() override; | |
182 friend struct DefaultSingletonTraits<SamplingThread>; | |
183 | |
184 // Get task runner that is usable from the outside. | |
185 scoped_refptr<SingleThreadTaskRunner> GetOrCreateTaskRunner(); | |
186 scoped_refptr<SingleThreadTaskRunner> GetTaskRunner(); | |
187 | |
188 // Get task runner that is usable from the sampling thread itself. | |
189 scoped_refptr<SingleThreadTaskRunner> GetTaskRunnerOnSamplingThread(); | |
190 | |
191 // Finishes a collection and reports collected data via callback. | |
192 void FinishCollection(CollectionContext* collection); | |
193 | |
194 // Records a single sample of a collection. | |
195 void RecordSample(CollectionContext* collection); | |
196 | |
197 // Check if the sampling thread is idle and begin a shutdown if so. | |
198 void ScheduleShutdownIfIdle(); | |
199 | |
200 // These methods are tasks that get posted to the internal message queue. | |
201 void AddCollectionTask(std::unique_ptr<CollectionContext> collection); | |
202 void RemoveCollectionTask(int id); | |
203 void PerformCollectionTask(int id); | |
204 void ShutdownTask(); | |
205 | |
206 // Updates the |next_sample_time| time based on configured parameters. | |
207 bool UpdateNextSampleTime(CollectionContext* collection); | |
208 | |
209 // Thread: | |
210 void CleanUp() override; | |
211 | |
212 // The task-runner for the sampling thread and some information about it. | |
213 // This must always be accessed while holding the lock. The saved task-runner | |
214 // can be freely used by any calling thread. | |
215 scoped_refptr<SingleThreadTaskRunner> task_runner_; | |
216 int task_runner_create_requests_ = 0; | |
217 TimeDelta task_runner_idle_shutdown_time_ = TimeDelta::FromSeconds(60); | |
218 Lock task_runner_lock_; | |
219 | |
220 // A map of IDs to collection contexts. Because this class is a singleton | |
221 // that is never destroyed, context objects will never be destructed except | |
222 // by explicit action. Thus, it's acceptable to pass unretained pointers | |
223 // to these objects when posting tasks. | |
224 std::map<int, std::unique_ptr<CollectionContext>> active_collections_; | |
225 | |
226 DISALLOW_COPY_AND_ASSIGN(SamplingThread); | |
227 }; | |
228 | |
229 StaticAtomicSequenceNumber StackSamplingProfiler::SamplingThread:: | |
230 CollectionContext::next_collection_id_; | |
231 | |
232 StackSamplingProfiler::SamplingThread::SamplingThread() | |
233 : Thread("Chrome_SamplingProfilerThread") {} | |
234 | |
235 StackSamplingProfiler::SamplingThread::~SamplingThread() { | |
236 Stop(); | |
237 } | |
238 | |
239 StackSamplingProfiler::SamplingThread* | |
240 StackSamplingProfiler::SamplingThread::GetInstance() { | |
241 return Singleton<SamplingThread, LeakySingletonTraits<SamplingThread>>::get(); | |
242 } | |
243 | |
244 void StackSamplingProfiler::SamplingThread::Start() { | |
245 Thread::Options options; | |
246 // Use a higher priority for a more accurate sampling interval. | |
247 options.priority = ThreadPriority::DISPLAY; | |
248 Thread::StartWithOptions(options); | |
249 } | |
250 | |
251 int StackSamplingProfiler::SamplingThread::Add( | |
252 std::unique_ptr<CollectionContext> collection) { | |
253 int id = collection->collection_id; | |
254 scoped_refptr<SingleThreadTaskRunner> task_runner = GetOrCreateTaskRunner(); | |
255 | |
256 task_runner->PostTask(FROM_HERE, Bind(&SamplingThread::AddCollectionTask, | |
257 Unretained(this), Passed(&collection))); | |
258 | |
259 return id; | |
260 } | |
261 | |
262 void StackSamplingProfiler::SamplingThread::Remove(int id) { | |
263 scoped_refptr<SingleThreadTaskRunner> task_runner = GetTaskRunner(); | |
264 if (!task_runner) | |
265 return; // Everything has already stopped. | |
266 | |
267 // This can fail if the thread were to exit between acquisition of the task | |
268 // runner above and the call below. In that case, however, everything has | |
269 // stopped so there's no need to try to stop it. | |
270 task_runner->PostTask(FROM_HERE, Bind(&SamplingThread::RemoveCollectionTask, | |
271 Unretained(this), id)); | |
272 } | |
273 | |
274 void StackSamplingProfiler::SamplingThread::ShutdownIfIdle() { | |
275 scoped_refptr<SingleThreadTaskRunner> task_runner = GetTaskRunner(); | |
276 if (!task_runner) | |
277 return; // Everything has already stopped. | |
278 | |
279 // ShutdownTask will check if the thread is idle and skip the shutdown if not. | |
280 task_runner->PostTask(FROM_HERE, | |
281 Bind(&SamplingThread::ShutdownTask, Unretained(this))); | |
282 } | |
283 | |
284 void StackSamplingProfiler::SamplingThread::SetIdleShutdownTime( | |
285 int shutdown_ms) { | |
286 AutoLock lock(task_runner_lock_); | |
287 task_runner_idle_shutdown_time_ = TimeDelta::FromMilliseconds(shutdown_ms); | |
288 } | |
289 | |
290 scoped_refptr<SingleThreadTaskRunner> | |
291 StackSamplingProfiler::SamplingThread::GetOrCreateTaskRunner() { | |
292 AutoLock lock(task_runner_lock_); | |
293 ++task_runner_create_requests_; | |
294 if (!task_runner_) { | |
295 // If this is not the first time the sampling thread has been launched, the | |
296 // previous instance has only been partially cleaned up. It is necessary | |
297 // to call Stop() before Start(). This is safe even the thread has never | |
298 // been started. | |
299 Stop(); | |
300 // The thread is not running. Start it and get associated runner. The task- | |
301 // runner has to be saved for future use because though it can be used from | |
302 // any thread, it can be acquired via task_runner() only on the created | |
303 // thread and the thread that creates it (i.e. this thread). | |
304 Start(); | |
305 task_runner_ = Thread::task_runner(); | |
306 // Detach the sampling thread from the "sequence" (i.e. thread) that | |
307 // started it so that it can be self-managed or stopped by another thread. | |
308 DetachFromSequence(); | |
309 } else { | |
310 // This shouldn't be called from the sampling thread as it's inefficient. | |
311 // Use GetTaskRunnerOnSamplingThread() instead. | |
312 DCHECK_NE(GetThreadId(), PlatformThread::CurrentId()); | |
313 } | |
314 | |
315 return task_runner_; | |
316 } | |
317 | |
318 scoped_refptr<SingleThreadTaskRunner> | |
319 StackSamplingProfiler::SamplingThread::GetTaskRunner() { | |
320 AutoLock lock(task_runner_lock_); | |
321 | |
322 // GetThreadId() will block for the thread to start so don't check if there | |
323 // is no task-runner. Otherwise, methods like Remove() will wait forever if | |
324 // the thread isn't already running when they could just return. | |
325 if (task_runner_) { | |
326 // This shouldn't be called from the sampling thread as it's inefficient. | |
327 // Use GetTaskRunnerOnSamplingThread() instead. | |
328 DCHECK_NE(GetThreadId(), PlatformThread::CurrentId()); | |
329 } | |
330 | |
331 return task_runner_; | |
332 } | |
333 | |
334 scoped_refptr<SingleThreadTaskRunner> | |
335 StackSamplingProfiler::SamplingThread::GetTaskRunnerOnSamplingThread() { | |
336 // This should be called only from the sampling thread as it has limited | |
337 // accessibility. | |
338 DCHECK_EQ(GetThreadId(), PlatformThread::CurrentId()); | |
339 | |
340 return Thread::task_runner(); | |
341 } | |
342 | |
343 void StackSamplingProfiler::SamplingThread::FinishCollection( | |
344 CollectionContext* collection) { | |
345 // If there is no duration for the final profile (because it was stopped), | |
346 // calculate it now. | |
347 if (!collection->profiles.empty() && | |
348 collection->profiles.back().profile_duration == TimeDelta()) { | |
349 collection->profiles.back().profile_duration = | |
350 Time::Now() - collection->profile_start_time; | |
351 } | |
352 | |
353 // Run the associated callback, passing the collected profiles. It's okay to | |
354 // move them because this collection is about to be deleted. | |
355 collection->callback.Run(std::move(collection->profiles)); | |
356 | |
357 // Signal that this collection is finished. | |
358 collection->finished->Signal(); | |
359 | |
360 // Remove this collection from the map of known ones. This must be done | |
361 // last as the |collection| parameter is invalid after this point. | |
362 size_t count = active_collections_.erase(collection->collection_id); | |
363 DCHECK_EQ(1U, count); | |
364 } | |
365 | |
366 void StackSamplingProfiler::SamplingThread::RecordSample( | |
367 CollectionContext* collection) { | |
368 DCHECK(collection->native_sampler); | |
369 | |
370 // If this is the first sample of a burst, a new Profile needs to be created | |
371 // and filled. | |
372 if (collection->sample == 0) { | |
373 collection->profiles.push_back(CallStackProfile()); | |
374 CallStackProfile& profile = collection->profiles.back(); | |
375 profile.sampling_period = collection->params.sampling_interval; | |
376 collection->profile_start_time = Time::Now(); | |
377 collection->native_sampler->ProfileRecordingStarting(&profile.modules); | |
378 } | |
379 | |
380 // The currently active profile being acptured. | |
Mike Wittman
2017/02/15 21:56:01
nit: captured
bcwhite
2017/02/16 17:39:49
Done.
| |
381 CallStackProfile& profile = collection->profiles.back(); | |
382 | |
383 // Record a single sample. | |
384 profile.samples.push_back(Sample()); | |
385 collection->native_sampler->RecordStackSample(&profile.samples.back()); | |
386 | |
387 // If this is the last sample of a burst, record the total time. | |
388 if (collection->sample == collection->params.samples_per_burst - 1) { | |
389 profile.profile_duration = Time::Now() - collection->profile_start_time; | |
390 collection->native_sampler->ProfileRecordingStopped(); | |
391 } | |
392 } | |
393 | |
394 void StackSamplingProfiler::SamplingThread::ScheduleShutdownIfIdle() { | |
395 if (!active_collections_.empty()) | |
181 return; | 396 return; |
182 | 397 |
183 CallStackProfiles profiles; | 398 AutoLock lock(task_runner_lock_); |
184 CollectProfiles(&profiles); | 399 if (!task_runner_idle_shutdown_time_.is_zero()) { |
185 concurrent_profiling_lock.Get().Release(); | 400 GetTaskRunnerOnSamplingThread()->PostDelayedTask( |
186 completed_callback_.Run(std::move(profiles)); | 401 FROM_HERE, Bind(&SamplingThread::ShutdownTask, Unretained(this)), |
187 } | 402 task_runner_idle_shutdown_time_); |
188 | 403 } |
189 // Depending on how long the sampling takes and the length of the sampling | 404 } |
190 // interval, a burst of samples could take arbitrarily longer than | 405 |
191 // samples_per_burst * sampling_interval. In this case, we (somewhat | 406 void StackSamplingProfiler::SamplingThread::AddCollectionTask( |
192 // arbitrarily) honor the number of samples requested rather than strictly | 407 std::unique_ptr<CollectionContext> collection) { |
193 // adhering to the sampling intervals. Once we have established users for the | 408 // Ownership of the collection is going to be given to a map so extract the |
194 // StackSamplingProfiler and the collected data to judge, we may go the other | 409 // information that will be needed from it below. |
195 // way or make this behavior configurable. | 410 const int collection_id = collection->collection_id; |
196 void StackSamplingProfiler::SamplingThread::CollectProfile( | 411 const TimeDelta initial_delay = collection->params.initial_delay; |
197 CallStackProfile* profile, | 412 |
198 TimeDelta* elapsed_time, | 413 active_collections_.insert( |
199 bool* was_stopped) { | 414 std::make_pair(collection_id, std::move(collection))); |
200 ElapsedTimer profile_timer; | 415 |
201 native_sampler_->ProfileRecordingStarting(&profile->modules); | 416 GetTaskRunnerOnSamplingThread()->PostDelayedTask( |
202 profile->sampling_period = params_.sampling_interval; | 417 FROM_HERE, Bind(&SamplingThread::PerformCollectionTask, Unretained(this), |
203 *was_stopped = false; | 418 collection_id), |
204 TimeDelta previous_elapsed_sample_time; | 419 initial_delay); |
205 for (int i = 0; i < params_.samples_per_burst; ++i) { | 420 } |
206 if (i != 0) { | 421 |
207 // Always wait, even if for 0 seconds, so we can observe a signal on | 422 void StackSamplingProfiler::SamplingThread::RemoveCollectionTask(int id) { |
208 // stop_event_. | 423 auto found = active_collections_.find(id); |
209 if (stop_event_.TimedWait( | 424 if (found == active_collections_.end()) |
210 std::max(params_.sampling_interval - previous_elapsed_sample_time, | |
211 TimeDelta()))) { | |
212 *was_stopped = true; | |
213 break; | |
214 } | |
215 } | |
216 ElapsedTimer sample_timer; | |
217 profile->samples.push_back(Sample()); | |
218 native_sampler_->RecordStackSample(&profile->samples.back()); | |
219 previous_elapsed_sample_time = sample_timer.Elapsed(); | |
220 } | |
221 | |
222 *elapsed_time = profile_timer.Elapsed(); | |
223 profile->profile_duration = *elapsed_time; | |
224 native_sampler_->ProfileRecordingStopped(); | |
225 } | |
226 | |
227 // In an analogous manner to CollectProfile() and samples exceeding the expected | |
228 // total sampling time, bursts may also exceed the burst_interval. We adopt the | |
229 // same wait-and-see approach here. | |
230 void StackSamplingProfiler::SamplingThread::CollectProfiles( | |
231 CallStackProfiles* profiles) { | |
232 if (stop_event_.TimedWait(params_.initial_delay)) | |
233 return; | 425 return; |
234 | 426 |
235 TimeDelta previous_elapsed_profile_time; | 427 FinishCollection(found->second.get()); |
236 for (int i = 0; i < params_.bursts; ++i) { | 428 ScheduleShutdownIfIdle(); |
237 if (i != 0) { | 429 } |
238 // Always wait, even if for 0 seconds, so we can observe a signal on | 430 |
239 // stop_event_. | 431 void StackSamplingProfiler::SamplingThread::PerformCollectionTask(int id) { |
240 if (stop_event_.TimedWait( | 432 auto found = active_collections_.find(id); |
241 std::max(params_.burst_interval - previous_elapsed_profile_time, | 433 |
242 TimeDelta()))) | 434 // The task won't be found if it has been stopped. |
243 return; | 435 if (found == active_collections_.end()) |
244 } | 436 return; |
245 | 437 |
246 CallStackProfile profile; | 438 CollectionContext* collection = found->second.get(); |
247 bool was_stopped = false; | 439 |
248 CollectProfile(&profile, &previous_elapsed_profile_time, &was_stopped); | 440 // Handle first-run with no "next time". |
249 if (!profile.samples.empty()) | 441 if (collection->next_sample_time == Time()) |
250 profiles->push_back(std::move(profile)); | 442 collection->next_sample_time = Time::Now(); |
251 | 443 |
252 if (was_stopped) | 444 // Do the collection of a single sample. |
253 return; | 445 RecordSample(collection); |
254 } | 446 |
255 } | 447 // Update the time of the next sample recording. |
256 | 448 if (UpdateNextSampleTime(collection)) { |
257 void StackSamplingProfiler::SamplingThread::Stop() { | 449 bool success = GetTaskRunnerOnSamplingThread()->PostDelayedTask( |
258 stop_event_.Signal(); | 450 FROM_HERE, |
451 Bind(&SamplingThread::PerformCollectionTask, Unretained(this), id), | |
452 std::max(collection->next_sample_time - Time::Now(), TimeDelta())); | |
453 DCHECK(success); | |
454 } else { | |
455 // All capturing has completed so finish the collection. Let object expire. | |
456 // The |collection| variable will be invalid after this call. | |
457 FinishCollection(collection); | |
458 ScheduleShutdownIfIdle(); | |
459 } | |
460 } | |
461 | |
462 void StackSamplingProfiler::SamplingThread::ShutdownTask() { | |
Mike Wittman
2017/02/15 21:56:01
I think need some kind of invalidation for Shutdow
bcwhite
2017/02/16 17:39:49
I can use the existing task_runner_create_requests
| |
463 // Holding this lock ensures that any attempt to start another job will | |
464 // get postponed until StopSoon can run thus eliminating the race. | |
465 AutoLock lock(task_runner_lock_); | |
466 | |
467 // If active_collections_ is not empty, something new has arrived since | |
468 // this task got posted. Abort the shutdown so it can be processed. | |
469 if (!active_collections_.empty()) | |
Mike Wittman
2017/02/15 21:56:01
Isn't this case already covered by the task_runner
bcwhite
2017/02/16 17:39:49
They happen at different times so something could
Mike Wittman
2017/02/17 16:10:19
Yeah, I can see that sequence of events occurring.
bcwhite
2017/02/21 16:21:19
Should. Since new collections could come in durin
Mike Wittman
2017/02/21 18:57:02
Actually, I think this should be:
2. Any delayed
| |
470 return; | |
471 // It's possible that a new AddCollectionTask has been posted after this | |
472 // task. Reset the "create requests" counter and try again after any other | |
473 // pending tasks. | |
474 if (task_runner_create_requests_ > 0 && task_runner_) { | |
475 task_runner_create_requests_ = 0; | |
476 task_runner_->PostTask( | |
477 FROM_HERE, Bind(&SamplingThread::ShutdownTask, Unretained(this))); | |
478 return; | |
479 } | |
480 | |
481 // There can be no new AddCollectionTasks at this point because creating | |
482 // those always increments "create requests". There may be other requests, | |
483 // like Remove, but it's okay to schedule the thread to stop once they've | |
484 // been executed (i.e. "soon"). | |
485 StopSoon(); | |
Mike Wittman
2017/02/15 21:56:01
One note on the Stop/StopSoon/DetachFromSequence c
bcwhite
2017/02/16 17:39:49
Acknowledged.
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486 | |
487 // StopSoon will have set the owning sequence (again) so it must be detached | |
488 // (again) in order for Stop/Start to be called (again) should more work | |
489 // come in. Holding the |task_runner_lock_| ensures the necessary happens- | |
490 // after with regard to this detach and future Thread API calls. | |
491 DetachFromSequence(); | |
492 | |
493 // Clear the task_runner_ variable so the thread will be restarted when | |
494 // new work comes in. | |
495 task_runner_ = nullptr; | |
496 } | |
497 | |
498 bool StackSamplingProfiler::SamplingThread::UpdateNextSampleTime( | |
499 CollectionContext* collection) { | |
500 // This will keep a consistent average interval between samples but will | |
501 // result in constant series of acquisitions, thus nearly locking out the | |
502 // target thread, if the interval is smaller than the time it takes to | |
503 // actually acquire the sample. Anything sampling that quickly is going | |
504 // to be a problem anyway so don't worry about it. | |
505 if (++collection->sample < collection->params.samples_per_burst) { | |
506 collection->next_sample_time += collection->params.sampling_interval; | |
507 return true; | |
508 } | |
509 | |
510 if (++collection->burst < collection->params.bursts) { | |
511 collection->sample = 0; | |
512 collection->next_sample_time += collection->params.burst_interval; | |
513 return true; | |
514 } | |
515 | |
516 return false; | |
517 } | |
518 | |
519 void StackSamplingProfiler::SamplingThread::CleanUp() { | |
520 // There should be no collections remaining when the thread stops. | |
521 DCHECK(active_collections_.empty()); | |
522 | |
523 // Let the parent clean up. | |
524 Thread::CleanUp(); | |
259 } | 525 } |
260 | 526 |
261 // StackSamplingProfiler ------------------------------------------------------ | 527 // StackSamplingProfiler ------------------------------------------------------ |
262 | 528 |
529 // static | |
530 bool StackSamplingProfiler::TestAPI::IsSamplingThreadRunning() { | |
531 return SamplingThread::GetInstance()->IsRunning(); | |
532 } | |
533 | |
534 // static | |
535 void StackSamplingProfiler::TestAPI::SetSamplingThreadIdleShutdownTime( | |
536 int shutdown_ms) { | |
537 SamplingThread::GetInstance()->SetIdleShutdownTime(shutdown_ms); | |
538 } | |
539 | |
540 // static | |
541 void StackSamplingProfiler::TestAPI::InitiateSamplingThreadIdleShutdown() { | |
542 SamplingThread::GetInstance()->ShutdownIfIdle(); | |
543 } | |
544 | |
263 subtle::Atomic32 StackSamplingProfiler::process_milestones_ = 0; | 545 subtle::Atomic32 StackSamplingProfiler::process_milestones_ = 0; |
264 | 546 |
265 StackSamplingProfiler::SamplingParams::SamplingParams() | 547 StackSamplingProfiler::SamplingParams::SamplingParams() |
266 : initial_delay(TimeDelta::FromMilliseconds(0)), | 548 : initial_delay(TimeDelta::FromMilliseconds(0)), |
267 bursts(1), | 549 bursts(1), |
268 burst_interval(TimeDelta::FromMilliseconds(10000)), | 550 burst_interval(TimeDelta::FromMilliseconds(10000)), |
269 samples_per_burst(300), | 551 samples_per_burst(300), |
270 sampling_interval(TimeDelta::FromMilliseconds(100)) { | 552 sampling_interval(TimeDelta::FromMilliseconds(100)) { |
271 } | 553 } |
272 | 554 |
273 StackSamplingProfiler::StackSamplingProfiler( | 555 StackSamplingProfiler::StackSamplingProfiler( |
274 PlatformThreadId thread_id, | |
275 const SamplingParams& params, | 556 const SamplingParams& params, |
276 const CompletedCallback& callback) | 557 const CompletedCallback& callback, |
277 : StackSamplingProfiler(thread_id, params, callback, nullptr) {} | 558 NativeStackSamplerTestDelegate* test_delegate) |
559 : StackSamplingProfiler(base::PlatformThread::CurrentId(), | |
560 params, | |
561 callback, | |
562 test_delegate) {} | |
278 | 563 |
279 StackSamplingProfiler::StackSamplingProfiler( | 564 StackSamplingProfiler::StackSamplingProfiler( |
280 PlatformThreadId thread_id, | 565 PlatformThreadId thread_id, |
281 const SamplingParams& params, | 566 const SamplingParams& params, |
282 const CompletedCallback& callback, | 567 const CompletedCallback& callback, |
283 NativeStackSamplerTestDelegate* test_delegate) | 568 NativeStackSamplerTestDelegate* test_delegate) |
284 : thread_id_(thread_id), params_(params), completed_callback_(callback), | 569 : thread_id_(thread_id), |
570 params_(params), | |
571 completed_callback_(callback), | |
572 finished_event_(WaitableEvent::ResetPolicy::MANUAL, | |
573 WaitableEvent::InitialState::NOT_SIGNALED), | |
285 test_delegate_(test_delegate) { | 574 test_delegate_(test_delegate) { |
575 native_sampler_ = NativeStackSampler::Create(thread_id_, &RecordAnnotations, | |
576 test_delegate_); | |
286 } | 577 } |
287 | 578 |
288 StackSamplingProfiler::~StackSamplingProfiler() { | 579 StackSamplingProfiler::~StackSamplingProfiler() { |
580 if (!native_sampler_) | |
581 return; | |
582 | |
583 // Stop is immediate but asynchronous. There is a non-zero probability that | |
584 // one more sample will be taken after this call returns. | |
289 Stop(); | 585 Stop(); |
290 if (!sampling_thread_handle_.is_null()) | 586 |
291 PlatformThread::Join(sampling_thread_handle_); | 587 // The behavior of sampling a thread that has exited is undefined and could |
588 // cause Bad Things(tm) to occur. The safety model provided by this class is | |
589 // that an instance of this object is expected to live at least as long as | |
590 // the thread it is sampling. However, because the sampling is performed | |
591 // asynchronously by the SamplingThread, there is no way to guarantee this | |
592 // is true without waiting for it to signal that it has finished. | |
593 // | |
594 // The wait time should, at most, be only as long as it takes to collect one | |
595 // sample (~200us) or none at all if sampling has already completed. | |
596 ThreadRestrictions::ScopedAllowWait allow_wait; | |
597 finished_event_.Wait(); | |
598 } | |
599 | |
600 void StackSamplingProfiler::Start() { | |
601 if (!native_sampler_ || completed_callback_.is_null()) | |
602 return; | |
603 | |
604 DCHECK_EQ(-1, collection_id_); | |
605 collection_id_ = SamplingThread::GetInstance()->Add( | |
606 MakeUnique<SamplingThread::CollectionContext>( | |
607 thread_id_, params_, completed_callback_, &finished_event_, | |
608 native_sampler_.get())); | |
609 DCHECK_NE(-1, collection_id_); | |
610 } | |
611 | |
612 void StackSamplingProfiler::Stop() { | |
613 if (!native_sampler_) | |
614 return; | |
615 | |
616 SamplingThread::GetInstance()->Remove(collection_id_); | |
617 collection_id_ = -1; | |
292 } | 618 } |
293 | 619 |
294 // static | 620 // static |
295 void StackSamplingProfiler::StartAndRunAsync( | |
296 PlatformThreadId thread_id, | |
297 const SamplingParams& params, | |
298 const CompletedCallback& callback) { | |
299 CHECK(ThreadTaskRunnerHandle::Get()); | |
300 AsyncRunner::Run(thread_id, params, callback); | |
301 } | |
302 | |
303 void StackSamplingProfiler::Start() { | |
304 if (completed_callback_.is_null()) | |
305 return; | |
306 | |
307 std::unique_ptr<NativeStackSampler> native_sampler = | |
308 NativeStackSampler::Create(thread_id_, &RecordAnnotations, | |
309 test_delegate_); | |
310 if (!native_sampler) | |
311 return; | |
312 | |
313 sampling_thread_.reset(new SamplingThread(std::move(native_sampler), params_, | |
314 completed_callback_)); | |
315 if (!PlatformThread::Create(0, sampling_thread_.get(), | |
316 &sampling_thread_handle_)) | |
317 sampling_thread_.reset(); | |
318 } | |
319 | |
320 void StackSamplingProfiler::Stop() { | |
321 if (sampling_thread_) | |
322 sampling_thread_->Stop(); | |
323 } | |
324 | |
325 // static | |
326 void StackSamplingProfiler::SetProcessMilestone(int milestone) { | 621 void StackSamplingProfiler::SetProcessMilestone(int milestone) { |
327 DCHECK_LE(0, milestone); | 622 DCHECK_LE(0, milestone); |
328 DCHECK_GT(static_cast<int>(sizeof(process_milestones_) * 8), milestone); | 623 DCHECK_GT(static_cast<int>(sizeof(process_milestones_) * 8), milestone); |
329 DCHECK_EQ(0, subtle::NoBarrier_Load(&process_milestones_) & (1 << milestone)); | 624 DCHECK_EQ(0, subtle::NoBarrier_Load(&process_milestones_) & (1 << milestone)); |
330 ChangeAtomicFlags(&process_milestones_, 1 << milestone, 0); | 625 ChangeAtomicFlags(&process_milestones_, 1 << milestone, 0); |
331 } | 626 } |
332 | 627 |
333 // static | 628 // static |
334 void StackSamplingProfiler::ResetAnnotationsForTesting() { | 629 void StackSamplingProfiler::ResetAnnotationsForTesting() { |
335 subtle::NoBarrier_Store(&process_milestones_, 0u); | 630 subtle::NoBarrier_Store(&process_milestones_, 0u); |
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378 } | 673 } |
379 | 674 |
380 bool operator<(const StackSamplingProfiler::Frame &a, | 675 bool operator<(const StackSamplingProfiler::Frame &a, |
381 const StackSamplingProfiler::Frame &b) { | 676 const StackSamplingProfiler::Frame &b) { |
382 return (a.module_index < b.module_index) || | 677 return (a.module_index < b.module_index) || |
383 (a.module_index == b.module_index && | 678 (a.module_index == b.module_index && |
384 a.instruction_pointer < b.instruction_pointer); | 679 a.instruction_pointer < b.instruction_pointer); |
385 } | 680 } |
386 | 681 |
387 } // namespace base | 682 } // namespace base |
OLD | NEW |