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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 #ifndef BASE_PROFILER_STACK_SAMPLING_PROFILER_H_ | 5 #ifndef BASE_PROFILER_STACK_SAMPLING_PROFILER_H_ |
6 #define BASE_PROFILER_STACK_SAMPLING_PROFILER_H_ | 6 #define BASE_PROFILER_STACK_SAMPLING_PROFILER_H_ |
7 | 7 |
8 #include <stddef.h> | 8 #include <stddef.h> |
9 | 9 |
10 #include <memory> | 10 #include <memory> |
11 #include <string> | 11 #include <string> |
12 #include <vector> | 12 #include <vector> |
13 | 13 |
14 #include "base/atomicops.h" | 14 #include "base/atomicops.h" |
15 #include "base/base_export.h" | 15 #include "base/base_export.h" |
16 #include "base/callback.h" | 16 #include "base/callback.h" |
17 #include "base/files/file_path.h" | 17 #include "base/files/file_path.h" |
18 #include "base/macros.h" | 18 #include "base/macros.h" |
19 #include "base/strings/string16.h" | 19 #include "base/strings/string16.h" |
20 #include "base/synchronization/waitable_event.h" | 20 #include "base/synchronization/waitable_event.h" |
21 #include "base/threading/platform_thread.h" | 21 #include "base/threading/platform_thread.h" |
22 #include "base/time/time.h" | 22 #include "base/time/time.h" |
23 | 23 |
24 namespace base { | 24 namespace base { |
25 | 25 |
26 class NativeStackSampler; | 26 class NativeStackSampler; |
27 class NativeStackSamplerTestDelegate; | 27 class NativeStackSamplerTestDelegate; |
| 28 class WaitableEvent; |
28 | 29 |
29 // StackSamplingProfiler periodically stops a thread to sample its stack, for | 30 // StackSamplingProfiler periodically stops a thread to sample its stack, for |
30 // the purpose of collecting information about which code paths are | 31 // the purpose of collecting information about which code paths are |
31 // executing. This information is used in aggregate by UMA to identify hot | 32 // executing. This information is used in aggregate by UMA to identify hot |
32 // and/or janky code paths. | 33 // and/or janky code paths. |
33 // | 34 // |
34 // Sample StackSamplingProfiler usage: | 35 // Sample StackSamplingProfiler usage: |
35 // | 36 // |
36 // // Create and customize params as desired. | 37 // // Create and customize params as desired. |
37 // base::StackStackSamplingProfiler::SamplingParams params; | 38 // base::StackStackSamplingProfiler::SamplingParams params; |
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175 | 176 |
176 // Number of samples to record per burst. Defaults to 300. | 177 // Number of samples to record per burst. Defaults to 300. |
177 int samples_per_burst; | 178 int samples_per_burst; |
178 | 179 |
179 // Interval between samples during a sampling burst. This is the desired | 180 // Interval between samples during a sampling burst. This is the desired |
180 // duration from the start of one sample to the start of the next | 181 // duration from the start of one sample to the start of the next |
181 // sample. Defaults to 100ms. | 182 // sample. Defaults to 100ms. |
182 TimeDelta sampling_interval; | 183 TimeDelta sampling_interval; |
183 }; | 184 }; |
184 | 185 |
| 186 // Testing support. |
| 187 class BASE_EXPORT TestAPI { |
| 188 public: |
| 189 // Returns whether the sampling thread is currently running or not. |
| 190 static bool IsSamplingThreadRunning(); |
| 191 |
| 192 // Sets the auto-shutdown delay time for the sampling thread, in ms. Set |
| 193 // this to zero to disable it. |
| 194 static void SetSamplingThreadIdleShutdownTime(int shutdown_ms); |
| 195 |
| 196 // Initiates an idle shutdown task, as though the idle timer had expired, |
| 197 // causing the thread to exit if there are no more sampling tasks pending. |
| 198 // This returns immediately. Watch IsSamplingThreadRunningForTesting() to |
| 199 // know when the thread has exited, though it will never do so if it is |
| 200 // not idle. |
| 201 static void InitiateSamplingThreadIdleShutdown(); |
| 202 }; |
| 203 |
185 // The callback type used to collect completed profiles. The passed |profiles| | 204 // The callback type used to collect completed profiles. The passed |profiles| |
186 // are move-only. | 205 // are move-only. Other threads, including the UI thread, may block on |
| 206 // callback completion so this should run as quickly as possible. |
187 // | 207 // |
188 // IMPORTANT NOTE: the callback is invoked on a thread the profiler | 208 // IMPORTANT NOTE: The callback is invoked on a thread the profiler |
189 // constructs, rather than on the thread used to construct the profiler and | 209 // constructs, rather than on the thread used to construct the profiler and |
190 // set the callback, and thus the callback must be callable on any thread. For | 210 // set the callback, and thus the callback must be callable on any thread. For |
191 // threads with message loops that create StackSamplingProfilers, posting a | 211 // threads with message loops that create StackSamplingProfilers, posting a |
192 // task to the message loop with a copy of the profiles is the recommended | 212 // task to the message loop with the moved (i.e. std::move) profiles is the |
193 // thread-safe callback implementation. | 213 // thread-safe callback implementation. |
194 using CompletedCallback = Callback<void(CallStackProfiles)>; | 214 using CompletedCallback = Callback<void(CallStackProfiles)>; |
195 | 215 |
196 // Creates a profiler that sends completed profiles to |callback|. The second | 216 // Creates a profiler for the CURRENT thread that sends completed profiles |
197 // constructor is for test purposes. | 217 // to |callback|. An optional |test_delegate| can be supplied by tests. |
198 StackSamplingProfiler(PlatformThreadId thread_id, | 218 // The caller must ensure that this object gets destroyed before the current |
199 const SamplingParams& params, | 219 // thread exits. |
200 const CompletedCallback& callback); | 220 StackSamplingProfiler( |
201 StackSamplingProfiler(PlatformThreadId thread_id, | 221 const SamplingParams& params, |
202 const SamplingParams& params, | 222 const CompletedCallback& callback, |
203 const CompletedCallback& callback, | 223 NativeStackSamplerTestDelegate* test_delegate = nullptr); |
204 NativeStackSamplerTestDelegate* test_delegate); | 224 |
| 225 // Creates a profiler for ANOTHER thread that sends completed profiles to |
| 226 // |callback|. An optional |test_delegate| can be supplied by tests. |
| 227 // |
| 228 // IMPORTANT: The caller must ensure that the thread being sampled does not |
| 229 // exit before this object gets destructed or Bad Things(tm) may occur. |
| 230 StackSamplingProfiler( |
| 231 PlatformThreadId thread_id, |
| 232 const SamplingParams& params, |
| 233 const CompletedCallback& callback, |
| 234 NativeStackSamplerTestDelegate* test_delegate = nullptr); |
| 235 |
205 // Stops any profiling currently taking place before destroying the profiler. | 236 // Stops any profiling currently taking place before destroying the profiler. |
| 237 // This will block until the callback has been run. |
206 ~StackSamplingProfiler(); | 238 ~StackSamplingProfiler(); |
207 | 239 |
208 // The fire-and-forget interface: starts a profiler and allows it to complete | |
209 // without the caller needing to manage the profiler lifetime. May be invoked | |
210 // from any thread, but requires that the calling thread has a message loop. | |
211 static void StartAndRunAsync(PlatformThreadId thread_id, | |
212 const SamplingParams& params, | |
213 const CompletedCallback& callback); | |
214 | |
215 // Initializes the profiler and starts sampling. | 240 // Initializes the profiler and starts sampling. |
216 void Start(); | 241 void Start(); |
217 | 242 |
218 // Stops the profiler and any ongoing sampling. Calling this function is | 243 // Stops the profiler and any ongoing sampling. This method will return |
219 // optional; if not invoked profiling terminates when all the profiling bursts | 244 // immediately with the callback being run asynchronously. At most one |
220 // specified in the SamplingParams are completed or the profiler is destroyed, | 245 // more stack sample will be taken after this method returns. Calling this |
221 // whichever occurs first. | 246 // function is optional; if not invoked profiling terminates when all the |
| 247 // profiling bursts specified in the SamplingParams are completed or the |
| 248 // profiler object is destroyed, whichever occurs first. |
222 void Stop(); | 249 void Stop(); |
223 | 250 |
224 // Set the current system state that is recorded with each captured stack | 251 // Set the current system state that is recorded with each captured stack |
225 // frame. This is thread-safe so can be called from anywhere. The parameter | 252 // frame. This is thread-safe so can be called from anywhere. The parameter |
226 // value should be from an enumeration of the appropriate type with values | 253 // value should be from an enumeration of the appropriate type with values |
227 // ranging from 0 to 31, inclusive. This sets bits within Sample field of | 254 // ranging from 0 to 31, inclusive. This sets bits within Sample field of |
228 // |process_milestones|. The actual meanings of these bits are defined | 255 // |process_milestones|. The actual meanings of these bits are defined |
229 // (globally) by the caller(s). | 256 // (globally) by the caller(s). |
230 static void SetProcessMilestone(int milestone); | 257 static void SetProcessMilestone(int milestone); |
231 static void ResetAnnotationsForTesting(); | 258 static void ResetAnnotationsForTesting(); |
232 | 259 |
233 private: | 260 private: |
| 261 friend class TestAPI; |
| 262 |
234 // SamplingThread is a separate thread used to suspend and sample stacks from | 263 // SamplingThread is a separate thread used to suspend and sample stacks from |
235 // the target thread. | 264 // the target thread. |
236 class SamplingThread : public PlatformThread::Delegate { | 265 class SamplingThread; |
237 public: | |
238 // Samples stacks using |native_sampler|. When complete, invokes | |
239 // |completed_callback| with the collected call stack profiles. | |
240 // |completed_callback| must be callable on any thread. | |
241 SamplingThread(std::unique_ptr<NativeStackSampler> native_sampler, | |
242 const SamplingParams& params, | |
243 const CompletedCallback& completed_callback); | |
244 ~SamplingThread() override; | |
245 | |
246 // PlatformThread::Delegate: | |
247 void ThreadMain() override; | |
248 | |
249 void Stop(); | |
250 | |
251 private: | |
252 // Collects |profile| from a single burst. If the profiler was stopped | |
253 // during collection, sets |was_stopped| and provides the set of samples | |
254 // collected up to that point. | |
255 void CollectProfile(CallStackProfile* profile, TimeDelta* elapsed_time, | |
256 bool* was_stopped); | |
257 | |
258 // Collects call stack profiles from all bursts, or until the sampling is | |
259 // stopped. If stopped before complete, the last profile in | |
260 // |call_stack_profiles| may contain a partial burst. | |
261 void CollectProfiles(CallStackProfiles* profiles); | |
262 | |
263 std::unique_ptr<NativeStackSampler> native_sampler_; | |
264 const SamplingParams params_; | |
265 | |
266 // If Stop() is called, it signals this event to force the sampling to | |
267 // terminate before all the samples specified in |params_| are collected. | |
268 WaitableEvent stop_event_; | |
269 | |
270 const CompletedCallback completed_callback_; | |
271 | |
272 DISALLOW_COPY_AND_ASSIGN(SamplingThread); | |
273 }; | |
274 | 266 |
275 // Adds annotations to a Sample. | 267 // Adds annotations to a Sample. |
276 static void RecordAnnotations(Sample* sample); | 268 static void RecordAnnotations(Sample* sample); |
277 | 269 |
278 // This global variables holds the current system state and is recorded with | 270 // This global variables holds the current system state and is recorded with |
279 // every captured sample, done on a separate thread which is why updates to | 271 // every captured sample, done on a separate thread which is why updates to |
280 // this must be atomic. A PostTask to move the the updates to that thread | 272 // this must be atomic. A PostTask to move the the updates to that thread |
281 // would skew the timing and a lock could result in deadlock if the thread | 273 // would skew the timing and a lock could result in deadlock if the thread |
282 // making a change was also being profiled and got stopped. | 274 // making a change was also being profiled and got stopped. |
283 static subtle::Atomic32 process_milestones_; | 275 static subtle::Atomic32 process_milestones_; |
284 | 276 |
285 // The thread whose stack will be sampled. | 277 // The thread whose stack will be sampled. |
286 PlatformThreadId thread_id_; | 278 PlatformThreadId thread_id_; |
287 | 279 |
288 const SamplingParams params_; | 280 const SamplingParams params_; |
289 | 281 |
290 std::unique_ptr<SamplingThread> sampling_thread_; | 282 const CompletedCallback completed_callback_; |
291 PlatformThreadHandle sampling_thread_handle_; | |
292 | 283 |
293 const CompletedCallback completed_callback_; | 284 // An event signaled when all sampling is complete and the callback done. |
| 285 WaitableEvent finished_event_; |
| 286 |
| 287 // Object that does the native sampling. This is created during construction |
| 288 // and later passed to the sampling thread when profiling is started. |
| 289 std::unique_ptr<NativeStackSampler> native_sampler_; |
| 290 |
| 291 // An ID uniquely identifying this collection to the sampling thread. |
| 292 int collection_id_; |
294 | 293 |
295 // Stored until it can be passed to the NativeStackSampler created in Start(). | 294 // Stored until it can be passed to the NativeStackSampler created in Start(). |
296 NativeStackSamplerTestDelegate* const test_delegate_; | 295 NativeStackSamplerTestDelegate* const test_delegate_; |
297 | 296 |
298 DISALLOW_COPY_AND_ASSIGN(StackSamplingProfiler); | 297 DISALLOW_COPY_AND_ASSIGN(StackSamplingProfiler); |
299 }; | 298 }; |
300 | 299 |
301 // These operators permit types to be compared and used in a map of Samples, as | 300 // These operators permit types to be compared and used in a map of Samples, as |
302 // done in tests and by the metrics provider code. | 301 // done in tests and by the metrics provider code. |
303 BASE_EXPORT bool operator==(const StackSamplingProfiler::Module& a, | 302 BASE_EXPORT bool operator==(const StackSamplingProfiler::Module& a, |
304 const StackSamplingProfiler::Module& b); | 303 const StackSamplingProfiler::Module& b); |
305 BASE_EXPORT bool operator==(const StackSamplingProfiler::Sample& a, | 304 BASE_EXPORT bool operator==(const StackSamplingProfiler::Sample& a, |
306 const StackSamplingProfiler::Sample& b); | 305 const StackSamplingProfiler::Sample& b); |
307 BASE_EXPORT bool operator!=(const StackSamplingProfiler::Sample& a, | 306 BASE_EXPORT bool operator!=(const StackSamplingProfiler::Sample& a, |
308 const StackSamplingProfiler::Sample& b); | 307 const StackSamplingProfiler::Sample& b); |
309 BASE_EXPORT bool operator<(const StackSamplingProfiler::Sample& a, | 308 BASE_EXPORT bool operator<(const StackSamplingProfiler::Sample& a, |
310 const StackSamplingProfiler::Sample& b); | 309 const StackSamplingProfiler::Sample& b); |
311 BASE_EXPORT bool operator==(const StackSamplingProfiler::Frame& a, | 310 BASE_EXPORT bool operator==(const StackSamplingProfiler::Frame& a, |
312 const StackSamplingProfiler::Frame& b); | 311 const StackSamplingProfiler::Frame& b); |
313 BASE_EXPORT bool operator<(const StackSamplingProfiler::Frame& a, | 312 BASE_EXPORT bool operator<(const StackSamplingProfiler::Frame& a, |
314 const StackSamplingProfiler::Frame& b); | 313 const StackSamplingProfiler::Frame& b); |
315 | 314 |
316 } // namespace base | 315 } // namespace base |
317 | 316 |
318 #endif // BASE_PROFILER_STACK_SAMPLING_PROFILER_H_ | 317 #endif // BASE_PROFILER_STACK_SAMPLING_PROFILER_H_ |
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