Index: base/profiler/stack_sampling_profiler.h |
diff --git a/base/profiler/stack_sampling_profiler.h b/base/profiler/stack_sampling_profiler.h |
index 622f6e5764a5b4e59fbf0a6eed6c7d328d737fc3..6f25d31fad8bffa8fcb34cab70641872468cb7a6 100644 |
--- a/base/profiler/stack_sampling_profiler.h |
+++ b/base/profiler/stack_sampling_profiler.h |
@@ -25,12 +25,20 @@ namespace base { |
class NativeStackSampler; |
class NativeStackSamplerTestDelegate; |
+class WaitableEvent; |
// StackSamplingProfiler periodically stops a thread to sample its stack, for |
// the purpose of collecting information about which code paths are |
// executing. This information is used in aggregate by UMA to identify hot |
// and/or janky code paths. |
// |
+// IMPORTANT: Only threads guaranteed to live beyond the lifetime of the |
+// profiler object can be safely sampled. Sampling the activity of the current |
+// thread within the scope of this object is safe, but sampling any other |
+// thread could cause Bad Things(tm) to occur should that thread exit before |
+// sampling is complete; ensure the profiler object gets destructed before |
+// exit of the thread under test. USE WITH CAUTION! |
+// |
Mike Wittman
2017/02/13 22:35:57
If we refactor the constructors to:
StackSampli
bcwhite
2017/02/14 14:33:02
I like it. Done.
|
// Sample StackSamplingProfiler usage: |
// |
// // Create and customize params as desired. |
@@ -205,13 +213,6 @@ class BASE_EXPORT StackSamplingProfiler { |
// Stops any profiling currently taking place before destroying the profiler. |
~StackSamplingProfiler(); |
- // The fire-and-forget interface: starts a profiler and allows it to complete |
- // without the caller needing to manage the profiler lifetime. May be invoked |
- // from any thread, but requires that the calling thread has a message loop. |
- static void StartAndRunAsync(PlatformThreadId thread_id, |
- const SamplingParams& params, |
- const CompletedCallback& callback); |
- |
// Initializes the profiler and starts sampling. |
void Start(); |
@@ -221,6 +222,27 @@ class BASE_EXPORT StackSamplingProfiler { |
// whichever occurs first. |
void Stop(); |
+ // Stops all active profiles and cleans up any resources in anticipation of |
+ // a shutdown of the current process. |
+ static void Shutdown(); |
+ |
+ // Resets the "shutdown" state so that the sampling thread can be restarted. |
+ static void UndoShutdownForTesting(); |
+ |
+ // Returns whether the sampling thread is currently running or not. |
+ static bool IsSamplingThreadRunningForTesting(); |
+ |
+ // Sets the auto-shutdown delay time for the sampling thread, in ms. Set this |
+ // to zero to disable it. |
+ static void SetSamplingThreadIdleShutdownTimeForTesting(int shutdown_ms); |
+ |
+ // Initiates an idle shutdown task, as though the idle timer had expired, |
+ // causing the thread to exit if there are no more sampling tasks pending. |
+ // This returns immediately. Watch IsSamplingThreadRunningForTesting() to |
+ // know when the thread has exited, though it will never do so if it is |
+ // not idle. |
+ static void InitiateSamplingThreadIdleShutdownForTesting(); |
+ |
// Set the current system state that is recorded with each captured stack |
// frame. This is thread-safe so can be called from anywhere. The parameter |
// value should be from an enumeration of the appropriate type with values |
@@ -233,44 +255,7 @@ class BASE_EXPORT StackSamplingProfiler { |
private: |
// SamplingThread is a separate thread used to suspend and sample stacks from |
// the target thread. |
- class SamplingThread : public PlatformThread::Delegate { |
- public: |
- // Samples stacks using |native_sampler|. When complete, invokes |
- // |completed_callback| with the collected call stack profiles. |
- // |completed_callback| must be callable on any thread. |
- SamplingThread(std::unique_ptr<NativeStackSampler> native_sampler, |
- const SamplingParams& params, |
- const CompletedCallback& completed_callback); |
- ~SamplingThread() override; |
- |
- // PlatformThread::Delegate: |
- void ThreadMain() override; |
- |
- void Stop(); |
- |
- private: |
- // Collects |profile| from a single burst. If the profiler was stopped |
- // during collection, sets |was_stopped| and provides the set of samples |
- // collected up to that point. |
- void CollectProfile(CallStackProfile* profile, TimeDelta* elapsed_time, |
- bool* was_stopped); |
- |
- // Collects call stack profiles from all bursts, or until the sampling is |
- // stopped. If stopped before complete, the last profile in |
- // |call_stack_profiles| may contain a partial burst. |
- void CollectProfiles(CallStackProfiles* profiles); |
- |
- std::unique_ptr<NativeStackSampler> native_sampler_; |
- const SamplingParams params_; |
- |
- // If Stop() is called, it signals this event to force the sampling to |
- // terminate before all the samples specified in |params_| are collected. |
- WaitableEvent stop_event_; |
- |
- const CompletedCallback completed_callback_; |
- |
- DISALLOW_COPY_AND_ASSIGN(SamplingThread); |
- }; |
+ class SamplingThread; |
// Adds annotations to a Sample. |
static void RecordAnnotations(Sample* sample); |
@@ -287,11 +272,18 @@ class BASE_EXPORT StackSamplingProfiler { |
const SamplingParams params_; |
- std::unique_ptr<SamplingThread> sampling_thread_; |
- PlatformThreadHandle sampling_thread_handle_; |
- |
const CompletedCallback completed_callback_; |
+ // An event signaled when all sampling is complete and the callback done. |
+ WaitableEvent finished_event_; |
+ |
+ // Object that does the native sampling. This is created during construction |
+ // and later passed to the sampling thread when profiling is started. |
+ std::unique_ptr<NativeStackSampler> native_sampler_; |
+ |
+ // An ID uniquely identifying this collection to the sampling thread. |
+ int collection_id_ = -1; |
+ |
// Stored until it can be passed to the NativeStackSampler created in Start(). |
NativeStackSamplerTestDelegate* const test_delegate_; |