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| 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 | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #ifndef COMPONENTS_SCHEDULER_CHILD_IDLE_HELPER_H_ | |
| 6 #define COMPONENTS_SCHEDULER_CHILD_IDLE_HELPER_H_ | |
| 7 | |
| 8 #include "base/macros.h" | |
| 9 #include "base/message_loop/message_loop.h" | |
| 10 #include "components/scheduler/base/cancelable_closure_holder.h" | |
| 11 #include "components/scheduler/base/task_queue_selector.h" | |
| 12 #include "components/scheduler/child/scheduler_helper.h" | |
| 13 #include "components/scheduler/child/single_thread_idle_task_runner.h" | |
| 14 #include "components/scheduler/scheduler_export.h" | |
| 15 | |
| 16 namespace scheduler { | |
| 17 | |
| 18 class SchedulerHelper; | |
| 19 | |
| 20 // Common scheduler functionality for Idle tasks. | |
| 21 class SCHEDULER_EXPORT IdleHelper | |
| 22 : public base::MessageLoop::TaskObserver, | |
| 23 public SingleThreadIdleTaskRunner::Delegate { | |
| 24 public: | |
| 25 // Used to by scheduler implementations to customize idle behaviour. | |
| 26 class SCHEDULER_EXPORT Delegate { | |
| 27 public: | |
| 28 Delegate(); | |
| 29 virtual ~Delegate(); | |
| 30 | |
| 31 // If it's ok to enter a long idle period, return true. Otherwise return | |
| 32 // false and set next_long_idle_period_delay_out so we know when to try | |
| 33 // again. | |
| 34 virtual bool CanEnterLongIdlePeriod( | |
| 35 base::TimeTicks now, | |
| 36 base::TimeDelta* next_long_idle_period_delay_out) = 0; | |
| 37 | |
| 38 // Signals that the Long Idle Period hasn't started yet because the system | |
| 39 // isn't quiescent. | |
| 40 virtual void IsNotQuiescent() = 0; | |
| 41 | |
| 42 // Signals that we have started an Idle Period. | |
| 43 virtual void OnIdlePeriodStarted() = 0; | |
| 44 | |
| 45 // Signals that we have finished an Idle Period. | |
| 46 virtual void OnIdlePeriodEnded() = 0; | |
| 47 | |
| 48 private: | |
| 49 DISALLOW_COPY_AND_ASSIGN(Delegate); | |
| 50 }; | |
| 51 | |
| 52 // Keep IdleHelper::IdlePeriodStateToString in sync with this enum. | |
| 53 enum class IdlePeriodState { | |
| 54 NOT_IN_IDLE_PERIOD, | |
| 55 IN_SHORT_IDLE_PERIOD, | |
| 56 IN_LONG_IDLE_PERIOD, | |
| 57 IN_LONG_IDLE_PERIOD_WITH_MAX_DEADLINE, | |
| 58 IN_LONG_IDLE_PERIOD_PAUSED, | |
| 59 // Must be the last entry. | |
| 60 IDLE_PERIOD_STATE_COUNT, | |
| 61 FIRST_IDLE_PERIOD_STATE = NOT_IN_IDLE_PERIOD, | |
| 62 }; | |
| 63 | |
| 64 // The maximum length of an idle period. | |
| 65 static const int kMaximumIdlePeriodMillis = 50; | |
| 66 | |
| 67 // |helper| and |delegate| are not owned by IdleHelper object and must | |
| 68 // outlive it. | |
| 69 IdleHelper( | |
| 70 SchedulerHelper* helper, | |
| 71 Delegate* delegate, | |
| 72 const char* tracing_category, | |
| 73 const char* disabled_by_default_tracing_category, | |
| 74 const char* idle_period_tracing_name, | |
| 75 base::TimeDelta required_quiescence_duration_before_long_idle_period); | |
| 76 ~IdleHelper() override; | |
| 77 | |
| 78 // Returns the idle task runner. Tasks posted to this runner may be reordered | |
| 79 // relative to other task types and may be starved for an arbitrarily long | |
| 80 // time if no idle time is available. | |
| 81 scoped_refptr<SingleThreadIdleTaskRunner> IdleTaskRunner(); | |
| 82 | |
| 83 // If |required_quiescence_duration_before_long_idle_period_| is zero then | |
| 84 // immediately initiate a long idle period, otherwise check if any tasks have | |
| 85 // run recently and if so, check again after a delay of | |
| 86 // |required_quiescence_duration_before_long_idle_period_|. | |
| 87 // Calling this function will end any previous idle period immediately, and | |
| 88 // potentially again later if | |
| 89 // |required_quiescence_duration_before_long_idle_period_| is non-zero. | |
| 90 // NOTE EndIdlePeriod will disable the long idle periods. | |
| 91 void EnableLongIdlePeriod(); | |
| 92 | |
| 93 // Start an idle period with a given idle period deadline. | |
| 94 void StartIdlePeriod(IdlePeriodState new_idle_period_state, | |
| 95 base::TimeTicks now, | |
| 96 base::TimeTicks idle_period_deadline); | |
| 97 | |
| 98 // This will end an idle period either started with StartIdlePeriod or | |
| 99 // EnableLongIdlePeriod. | |
| 100 void EndIdlePeriod(); | |
| 101 | |
| 102 // Returns true if a currently running idle task could exceed its deadline | |
| 103 // without impacting user experience too much. This should only be used if | |
| 104 // there is a task which cannot be pre-empted and is likely to take longer | |
| 105 // than the largest expected idle task deadline. It should NOT be polled to | |
| 106 // check whether more work can be performed on the current idle task after | |
| 107 // its deadline has expired - post a new idle task for the continuation of the | |
| 108 // work in this case. | |
| 109 // Must be called from the thread this class was created on. | |
| 110 bool CanExceedIdleDeadlineIfRequired() const; | |
| 111 | |
| 112 // Returns the deadline for the current idle task. | |
| 113 base::TimeTicks CurrentIdleTaskDeadline() const; | |
| 114 | |
| 115 // SingleThreadIdleTaskRunner::Delegate implementation: | |
| 116 void OnIdleTaskPosted() override; | |
| 117 base::TimeTicks WillProcessIdleTask() override; | |
| 118 void DidProcessIdleTask() override; | |
| 119 | |
| 120 // base::MessageLoop::TaskObserver implementation: | |
| 121 void WillProcessTask(const base::PendingTask& pending_task) override; | |
| 122 void DidProcessTask(const base::PendingTask& pending_task) override; | |
| 123 | |
| 124 IdlePeriodState SchedulerIdlePeriodState() const; | |
| 125 static const char* IdlePeriodStateToString(IdlePeriodState state); | |
| 126 | |
| 127 private: | |
| 128 friend class BaseIdleHelperTest; | |
| 129 friend class IdleHelperTest; | |
| 130 | |
| 131 class State { | |
| 132 public: | |
| 133 State(SchedulerHelper* helper, | |
| 134 Delegate* delegate, | |
| 135 const char* tracing_category, | |
| 136 const char* disabled_by_default_tracing_category, | |
| 137 const char* idle_period_tracing_name); | |
| 138 virtual ~State(); | |
| 139 | |
| 140 void UpdateState(IdlePeriodState new_state, | |
| 141 base::TimeTicks new_deadline, | |
| 142 base::TimeTicks optional_now); | |
| 143 bool IsIdlePeriodPaused() const; | |
| 144 | |
| 145 IdlePeriodState idle_period_state() const; | |
| 146 base::TimeTicks idle_period_deadline() const; | |
| 147 | |
| 148 void TraceIdleIdleTaskStart(); | |
| 149 void TraceIdleIdleTaskEnd(); | |
| 150 | |
| 151 private: | |
| 152 void TraceEventIdlePeriodStateChange(IdlePeriodState new_state, | |
| 153 bool new_running_idle_task, | |
| 154 base::TimeTicks new_deadline, | |
| 155 base::TimeTicks optional_now); | |
| 156 | |
| 157 SchedulerHelper* helper_; // NOT OWNED | |
| 158 Delegate* delegate_; // NOT OWNED | |
| 159 | |
| 160 IdlePeriodState idle_period_state_; | |
| 161 base::TimeTicks idle_period_deadline_; | |
| 162 | |
| 163 base::TimeTicks last_idle_task_trace_time_; | |
| 164 bool idle_period_trace_event_started_; | |
| 165 bool running_idle_task_for_tracing_; | |
| 166 const char* tracing_category_; | |
| 167 const char* disabled_by_default_tracing_category_; | |
| 168 const char* idle_period_tracing_name_; | |
| 169 | |
| 170 DISALLOW_COPY_AND_ASSIGN(State); | |
| 171 }; | |
| 172 | |
| 173 // The minimum duration of an idle period. | |
| 174 static const int kMinimumIdlePeriodDurationMillis = 1; | |
| 175 | |
| 176 // The minimum delay to wait between retrying to initiate a long idle time. | |
| 177 static const int kRetryEnableLongIdlePeriodDelayMillis = 1; | |
| 178 | |
| 179 // Returns the new idle period state for the next long idle period. Fills in | |
| 180 // |next_long_idle_period_delay_out| with the next time we should try to | |
| 181 // initiate the next idle period. | |
| 182 IdlePeriodState ComputeNewLongIdlePeriodState( | |
| 183 const base::TimeTicks now, | |
| 184 base::TimeDelta* next_long_idle_period_delay_out); | |
| 185 | |
| 186 bool ShouldWaitForQuiescence(); | |
| 187 void OnIdleTaskPostedOnMainThread(); | |
| 188 void UpdateLongIdlePeriodStateAfterIdleTask(); | |
| 189 | |
| 190 void SetIdlePeriodState(IdlePeriodState new_state, | |
| 191 base::TimeTicks new_deadline, | |
| 192 base::TimeTicks optional_now); | |
| 193 | |
| 194 // Returns true if |state| represents being within an idle period state. | |
| 195 static bool IsInIdlePeriod(IdlePeriodState state); | |
| 196 // Returns true if |state| represents being within a long idle period state. | |
| 197 static bool IsInLongIdlePeriod(IdlePeriodState state); | |
| 198 | |
| 199 SchedulerHelper* helper_; // NOT OWNED | |
| 200 Delegate* delegate_; // NOT OWNED | |
| 201 scoped_refptr<TaskQueue> idle_queue_; | |
| 202 scoped_refptr<SingleThreadIdleTaskRunner> idle_task_runner_; | |
| 203 | |
| 204 CancelableClosureHolder enable_next_long_idle_period_closure_; | |
| 205 CancelableClosureHolder on_idle_task_posted_closure_; | |
| 206 | |
| 207 State state_; | |
| 208 | |
| 209 base::TimeDelta required_quiescence_duration_before_long_idle_period_; | |
| 210 | |
| 211 const char* disabled_by_default_tracing_category_; | |
| 212 | |
| 213 base::WeakPtr<IdleHelper> weak_idle_helper_ptr_; | |
| 214 base::WeakPtrFactory<IdleHelper> weak_factory_; | |
| 215 | |
| 216 DISALLOW_COPY_AND_ASSIGN(IdleHelper); | |
| 217 }; | |
| 218 | |
| 219 } // namespace scheduler | |
| 220 | |
| 221 #endif // COMPONENTS_SCHEDULER_CHILD_IDLE_HELPER_H_ | |
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Chromium Code Reviews
Issue 2118903002:
scheduler: Move the Blink scheduler into Blink (Closed)
Base URL: https://chromium.googlesource.com/chromium/src.git@master