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1 // Copyright 2016 The Chromium Authors. All rights reserved. | 1 // Copyright 2016 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_TASK_SCHEDULER_TASK_TRACKER_H_ | 5 #ifndef BASE_TASK_SCHEDULER_TASK_TRACKER_H_ |
6 #define BASE_TASK_SCHEDULER_TASK_TRACKER_H_ | 6 #define BASE_TASK_SCHEDULER_TASK_TRACKER_H_ |
7 | 7 |
8 #include <memory> | 8 #include <memory> |
9 | 9 |
10 #include "base/atomicops.h" | 10 #include "base/atomicops.h" |
11 #include "base/base_export.h" | 11 #include "base/base_export.h" |
12 #include "base/callback_forward.h" | 12 #include "base/callback_forward.h" |
13 #include "base/gtest_prod_util.h" | |
13 #include "base/macros.h" | 14 #include "base/macros.h" |
14 #include "base/metrics/histogram_base.h" | 15 #include "base/metrics/histogram_base.h" |
15 #include "base/synchronization/waitable_event.h" | 16 #include "base/synchronization/waitable_event.h" |
16 #include "base/task_scheduler/scheduler_lock.h" | 17 #include "base/task_scheduler/scheduler_lock.h" |
17 #include "base/task_scheduler/sequence.h" | 18 #include "base/task_scheduler/sequence.h" |
18 #include "base/task_scheduler/task.h" | 19 #include "base/task_scheduler/task.h" |
19 #include "base/task_scheduler/task_traits.h" | 20 #include "base/task_scheduler/task_traits.h" |
20 | 21 |
21 namespace base { | 22 namespace base { |
22 | 23 |
23 class ConditionVariable; | 24 class ConditionVariable; |
25 class HistogramBase; | |
24 class SequenceToken; | 26 class SequenceToken; |
25 | 27 |
26 namespace internal { | 28 namespace internal { |
27 | 29 |
28 // All tasks go through the scheduler's TaskTracker when they are posted and | 30 // All tasks go through the scheduler's TaskTracker when they are posted and |
29 // when they are executed. The TaskTracker enforces shutdown semantics and takes | 31 // when they are executed. The TaskTracker sets up the environment to run tasks, |
30 // care of tracing and profiling. This class is thread-safe. | 32 // enforces shutdown semantics, records metrics, and takes care of tracing and |
33 // profiling. This class is thread-safe. | |
31 class BASE_EXPORT TaskTracker { | 34 class BASE_EXPORT TaskTracker { |
32 public: | 35 public: |
33 TaskTracker(); | 36 TaskTracker(); |
34 ~TaskTracker(); | 37 ~TaskTracker(); |
35 | 38 |
36 // Synchronously shuts down the scheduler. Once this is called, only tasks | 39 // Synchronously shuts down the scheduler. Once this is called, only tasks |
37 // posted with the BLOCK_SHUTDOWN behavior will be run. Returns when: | 40 // posted with the BLOCK_SHUTDOWN behavior will be run. Returns when: |
38 // - All SKIP_ON_SHUTDOWN tasks that were already running have completed their | 41 // - All SKIP_ON_SHUTDOWN tasks that were already running have completed their |
39 // execution. | 42 // execution. |
40 // - All posted BLOCK_SHUTDOWN tasks have completed their execution. | 43 // - All posted BLOCK_SHUTDOWN tasks have completed their execution. |
(...skipping 31 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading... | |
72 // IsShutdownComplete() won't return true after this returns. Shutdown() | 75 // IsShutdownComplete() won't return true after this returns. Shutdown() |
73 // cannot be called after this. | 76 // cannot be called after this. |
74 void SetHasShutdownStartedForTesting(); | 77 void SetHasShutdownStartedForTesting(); |
75 | 78 |
76 protected: | 79 protected: |
77 // Runs |task|. An override is expected to call its parent's implementation | 80 // Runs |task|. An override is expected to call its parent's implementation |
78 // but is free to perform extra work before and after doing so. | 81 // but is free to perform extra work before and after doing so. |
79 virtual void PerformRunTask(std::unique_ptr<Task> task); | 82 virtual void PerformRunTask(std::unique_ptr<Task> task); |
80 | 83 |
81 private: | 84 private: |
85 FRIEND_TEST_ALL_PREFIXES(TaskSchedulerTaskTrackerHistogramTest, TaskLatency); | |
gab
2017/01/05 22:16:36
Drop friend?
fdoray
2017/01/05 22:31:58
Done.
| |
86 | |
82 class State; | 87 class State; |
83 | 88 |
84 void PerformShutdown(); | 89 void PerformShutdown(); |
85 | 90 |
86 // Called before WillPostTask() informs the tracing system that a task has | 91 // Called before WillPostTask() informs the tracing system that a task has |
87 // been posted. Updates |num_tasks_blocking_shutdown_| if necessary and | 92 // been posted. Updates |num_tasks_blocking_shutdown_| if necessary and |
88 // returns true if the current shutdown state allows the task to be posted. | 93 // returns true if the current shutdown state allows the task to be posted. |
89 bool BeforePostTask(TaskShutdownBehavior shutdown_behavior); | 94 bool BeforePostTask(TaskShutdownBehavior shutdown_behavior); |
90 | 95 |
91 // Called before a task with |shutdown_behavior| is run by RunTask(). Updates | 96 // Called before a task with |shutdown_behavior| is run by RunTask(). Updates |
92 // |num_tasks_blocking_shutdown_| if necessary and returns true if the current | 97 // |num_tasks_blocking_shutdown_| if necessary and returns true if the current |
93 // shutdown state allows the task to be run. | 98 // shutdown state allows the task to be run. |
94 bool BeforeRunTask(TaskShutdownBehavior shutdown_behavior); | 99 bool BeforeRunTask(TaskShutdownBehavior shutdown_behavior); |
95 | 100 |
96 // Called after a task with |shutdown_behavior| has been run by RunTask(). | 101 // Called after a task with |shutdown_behavior| has been run by RunTask(). |
97 // Updates |num_tasks_blocking_shutdown_| and signals |shutdown_cv_| if | 102 // Updates |num_tasks_blocking_shutdown_| and signals |shutdown_cv_| if |
98 // necessary. | 103 // necessary. |
99 void AfterRunTask(TaskShutdownBehavior shutdown_behavior); | 104 void AfterRunTask(TaskShutdownBehavior shutdown_behavior); |
100 | 105 |
101 // Called when the number of tasks blocking shutdown becomes zero after | 106 // Called when the number of tasks blocking shutdown becomes zero after |
102 // shutdown has started. | 107 // shutdown has started. |
103 void OnBlockingShutdownTasksComplete(); | 108 void OnBlockingShutdownTasksComplete(); |
104 | 109 |
105 // Decrements the number of pending undelayed tasks and signals |flush_cv_| if | 110 // Decrements the number of pending undelayed tasks and signals |flush_cv_| if |
106 // it reaches zero. | 111 // it reaches zero. |
107 void DecrementNumPendingUndelayedTasks(); | 112 void DecrementNumPendingUndelayedTasks(); |
108 | 113 |
114 // Records the TaskScheduler.TaskLatency.[task priority].[may block] histogram | |
115 // for |task|. | |
116 void RecordTaskLatencyHistogram(Task* task); | |
117 | |
109 // Number of tasks blocking shutdown and boolean indicating whether shutdown | 118 // Number of tasks blocking shutdown and boolean indicating whether shutdown |
110 // has started. | 119 // has started. |
111 const std::unique_ptr<State> state_; | 120 const std::unique_ptr<State> state_; |
112 | 121 |
113 // Number of undelayed tasks that haven't completed their execution. Is | 122 // Number of undelayed tasks that haven't completed their execution. Is |
114 // incremented and decremented without a barrier. When it reaches zero, | 123 // incremented and decremented without a barrier. When it reaches zero, |
115 // |flush_lock_| is acquired (forcing memory synchronization) and |flush_cv_| | 124 // |flush_lock_| is acquired (forcing memory synchronization) and |flush_cv_| |
116 // is signaled. | 125 // is signaled. |
117 subtle::Atomic32 num_pending_undelayed_tasks_ = 0; | 126 subtle::Atomic32 num_pending_undelayed_tasks_ = 0; |
118 | 127 |
119 // Lock associated with |flush_cv_|. Partially synchronizes access to | 128 // Lock associated with |flush_cv_|. Partially synchronizes access to |
120 // |num_pending_undelayed_tasks_|. Full synchronization isn't needed because | 129 // |num_pending_undelayed_tasks_|. Full synchronization isn't needed because |
121 // it's atomic, but synchronization is needed to coordinate waking and | 130 // it's atomic, but synchronization is needed to coordinate waking and |
122 // sleeping at the right time. | 131 // sleeping at the right time. |
123 mutable SchedulerLock flush_lock_; | 132 mutable SchedulerLock flush_lock_; |
124 | 133 |
125 // Signaled when |num_pending_undelayed_tasks_| is zero or when shutdown | 134 // Signaled when |num_pending_undelayed_tasks_| is zero or when shutdown |
126 // completes. | 135 // completes. |
127 const std::unique_ptr<ConditionVariable> flush_cv_; | 136 const std::unique_ptr<ConditionVariable> flush_cv_; |
128 | 137 |
129 // Synchronizes access to shutdown related members below. | 138 // Synchronizes access to shutdown related members below. |
130 mutable SchedulerLock shutdown_lock_; | 139 mutable SchedulerLock shutdown_lock_; |
131 | 140 |
132 // Event instantiated when shutdown starts and signaled when shutdown | 141 // Event instantiated when shutdown starts and signaled when shutdown |
133 // completes. | 142 // completes. |
134 std::unique_ptr<WaitableEvent> shutdown_event_; | 143 std::unique_ptr<WaitableEvent> shutdown_event_; |
135 | 144 |
145 // TaskScheduler.TaskLatency.[task priority].[may block] histograms. The first | |
146 // index is a TaskPriority. The second index is 0 for non-blocking tasks, 1 | |
147 // for blocking tasks. Intentionally leaked. | |
148 HistogramBase* const | |
149 task_latency_histograms_[static_cast<int>(TaskPriority::HIGHEST) + 1][2]; | |
150 | |
136 // Number of BLOCK_SHUTDOWN tasks posted during shutdown. | 151 // Number of BLOCK_SHUTDOWN tasks posted during shutdown. |
137 HistogramBase::Sample num_block_shutdown_tasks_posted_during_shutdown_ = 0; | 152 HistogramBase::Sample num_block_shutdown_tasks_posted_during_shutdown_ = 0; |
138 | 153 |
139 DISALLOW_COPY_AND_ASSIGN(TaskTracker); | 154 DISALLOW_COPY_AND_ASSIGN(TaskTracker); |
140 }; | 155 }; |
141 | 156 |
142 } // namespace internal | 157 } // namespace internal |
143 } // namespace base | 158 } // namespace base |
144 | 159 |
145 #endif // BASE_TASK_SCHEDULER_TASK_TRACKER_H_ | 160 #endif // BASE_TASK_SCHEDULER_TASK_TRACKER_H_ |
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