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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 #include "components/scheduler/renderer/throttling_helper.h" | |
6 | |
7 #include "base/logging.h" | |
8 #include "components/scheduler/base/real_time_domain.h" | |
9 #include "components/scheduler/child/scheduler_tqm_delegate.h" | |
10 #include "components/scheduler/renderer/auto_advancing_virtual_time_domain.h" | |
11 #include "components/scheduler/renderer/renderer_scheduler_impl.h" | |
12 #include "components/scheduler/renderer/throttled_time_domain.h" | |
13 #include "components/scheduler/renderer/web_frame_scheduler_impl.h" | |
14 #include "third_party/WebKit/public/platform/WebFrameScheduler.h" | |
15 | |
16 namespace scheduler { | |
17 | |
18 ThrottlingHelper::ThrottlingHelper(RendererSchedulerImpl* renderer_scheduler, | |
19 const char* tracing_category) | |
20 : task_runner_(renderer_scheduler->ControlTaskRunner()), | |
21 renderer_scheduler_(renderer_scheduler), | |
22 tick_clock_(renderer_scheduler->tick_clock()), | |
23 tracing_category_(tracing_category), | |
24 time_domain_(new ThrottledTimeDomain(this, tracing_category)), | |
25 virtual_time_(false), | |
26 weak_factory_(this) { | |
27 pump_throttled_tasks_closure_.Reset(base::Bind( | |
28 &ThrottlingHelper::PumpThrottledTasks, weak_factory_.GetWeakPtr())); | |
29 forward_immediate_work_closure_ = | |
30 base::Bind(&ThrottlingHelper::OnTimeDomainHasImmediateWork, | |
31 weak_factory_.GetWeakPtr()); | |
32 | |
33 renderer_scheduler_->RegisterTimeDomain(time_domain_.get()); | |
34 } | |
35 | |
36 ThrottlingHelper::~ThrottlingHelper() { | |
37 // It's possible for queues to be still throttled, so we need to tidy up | |
38 // before unregistering the time domain. | |
39 for (const TaskQueueMap::value_type& map_entry : throttled_queues_) { | |
40 TaskQueue* task_queue = map_entry.first; | |
41 task_queue->SetTimeDomain(renderer_scheduler_->real_time_domain()); | |
42 task_queue->SetPumpPolicy(TaskQueue::PumpPolicy::AUTO); | |
43 } | |
44 | |
45 renderer_scheduler_->UnregisterTimeDomain(time_domain_.get()); | |
46 } | |
47 | |
48 void ThrottlingHelper::SetQueueEnabled(TaskQueue* task_queue, bool enabled) { | |
49 TaskQueueMap::iterator find_it = throttled_queues_.find(task_queue); | |
50 | |
51 if (find_it == throttled_queues_.end()) { | |
52 task_queue->SetQueueEnabled(enabled); | |
53 return; | |
54 } | |
55 | |
56 find_it->second.enabled = enabled; | |
57 | |
58 // We don't enable the queue here because it's throttled and there might be | |
59 // tasks in it's work queue that would execute immediatly rather than after | |
60 // PumpThrottledTasks runs. | |
61 if (!enabled) | |
62 task_queue->SetQueueEnabled(false); | |
63 } | |
64 | |
65 void ThrottlingHelper::IncreaseThrottleRefCount(TaskQueue* task_queue) { | |
66 DCHECK_NE(task_queue, task_runner_.get()); | |
67 | |
68 if (virtual_time_) | |
69 return; | |
70 | |
71 std::pair<TaskQueueMap::iterator, bool> insert_result = | |
72 throttled_queues_.insert(std::make_pair( | |
73 task_queue, Metadata(1, task_queue->IsQueueEnabled()))); | |
74 | |
75 if (insert_result.second) { | |
76 // The insert was succesful so we need to throttle the queue. | |
77 task_queue->SetTimeDomain(time_domain_.get()); | |
78 task_queue->SetPumpPolicy(TaskQueue::PumpPolicy::MANUAL); | |
79 task_queue->SetQueueEnabled(false); | |
80 | |
81 if (!task_queue->IsEmpty()) { | |
82 if (task_queue->HasPendingImmediateWork()) { | |
83 OnTimeDomainHasImmediateWork(); | |
84 } else { | |
85 OnTimeDomainHasDelayedWork(); | |
86 } | |
87 } | |
88 } else { | |
89 // An entry already existed in the map so we need to increment the refcount. | |
90 insert_result.first->second.throttling_ref_count++; | |
91 } | |
92 } | |
93 | |
94 void ThrottlingHelper::DecreaseThrottleRefCount(TaskQueue* task_queue) { | |
95 if (virtual_time_) | |
96 return; | |
97 | |
98 TaskQueueMap::iterator iter = throttled_queues_.find(task_queue); | |
99 | |
100 if (iter != throttled_queues_.end() && | |
101 --iter->second.throttling_ref_count == 0) { | |
102 bool enabled = iter->second.enabled; | |
103 // The refcount has become zero, we need to unthrottle the queue. | |
104 throttled_queues_.erase(iter); | |
105 | |
106 task_queue->SetTimeDomain(renderer_scheduler_->real_time_domain()); | |
107 task_queue->SetPumpPolicy(TaskQueue::PumpPolicy::AUTO); | |
108 task_queue->SetQueueEnabled(enabled); | |
109 } | |
110 } | |
111 | |
112 void ThrottlingHelper::UnregisterTaskQueue(TaskQueue* task_queue) { | |
113 throttled_queues_.erase(task_queue); | |
114 } | |
115 | |
116 void ThrottlingHelper::OnTimeDomainHasImmediateWork() { | |
117 // Forward to the main thread if called from another thread. | |
118 if (!task_runner_->RunsTasksOnCurrentThread()) { | |
119 task_runner_->PostTask(FROM_HERE, forward_immediate_work_closure_); | |
120 return; | |
121 } | |
122 TRACE_EVENT0(tracing_category_, | |
123 "ThrottlingHelper::OnTimeDomainHasImmediateWork"); | |
124 base::TimeTicks now = tick_clock_->NowTicks(); | |
125 MaybeSchedulePumpThrottledTasksLocked(FROM_HERE, now, now); | |
126 } | |
127 | |
128 void ThrottlingHelper::OnTimeDomainHasDelayedWork() { | |
129 TRACE_EVENT0(tracing_category_, | |
130 "ThrottlingHelper::OnTimeDomainHasDelayedWork"); | |
131 base::TimeTicks next_scheduled_delayed_task; | |
132 bool has_delayed_task = | |
133 time_domain_->NextScheduledRunTime(&next_scheduled_delayed_task); | |
134 DCHECK(has_delayed_task); | |
135 base::TimeTicks now = tick_clock_->NowTicks(); | |
136 MaybeSchedulePumpThrottledTasksLocked(FROM_HERE, now, | |
137 next_scheduled_delayed_task); | |
138 } | |
139 | |
140 void ThrottlingHelper::PumpThrottledTasks() { | |
141 TRACE_EVENT0(tracing_category_, "ThrottlingHelper::PumpThrottledTasks"); | |
142 pending_pump_throttled_tasks_runtime_ = base::TimeTicks(); | |
143 | |
144 LazyNow lazy_low(tick_clock_); | |
145 for (const TaskQueueMap::value_type& map_entry : throttled_queues_) { | |
146 TaskQueue* task_queue = map_entry.first; | |
147 if (task_queue->IsEmpty()) | |
148 continue; | |
149 | |
150 task_queue->SetQueueEnabled(map_entry.second.enabled); | |
151 task_queue->PumpQueue(&lazy_low, false); | |
152 } | |
153 // Make sure NextScheduledRunTime gives us an up-to date result. | |
154 time_domain_->ClearExpiredWakeups(); | |
155 | |
156 base::TimeTicks next_scheduled_delayed_task; | |
157 // Maybe schedule a call to ThrottlingHelper::PumpThrottledTasks if there is | |
158 // a pending delayed task. NOTE posting a non-delayed task in the future will | |
159 // result in ThrottlingHelper::OnTimeDomainHasImmediateWork being called. | |
160 if (time_domain_->NextScheduledRunTime(&next_scheduled_delayed_task)) { | |
161 MaybeSchedulePumpThrottledTasksLocked(FROM_HERE, lazy_low.Now(), | |
162 next_scheduled_delayed_task); | |
163 } | |
164 } | |
165 | |
166 /* static */ | |
167 base::TimeTicks ThrottlingHelper::ThrottledRunTime( | |
168 base::TimeTicks unthrottled_runtime) { | |
169 const base::TimeDelta one_second = base::TimeDelta::FromSeconds(1); | |
170 return unthrottled_runtime + one_second - | |
171 ((unthrottled_runtime - base::TimeTicks()) % one_second); | |
172 } | |
173 | |
174 void ThrottlingHelper::MaybeSchedulePumpThrottledTasksLocked( | |
175 const tracked_objects::Location& from_here, | |
176 base::TimeTicks now, | |
177 base::TimeTicks unthrottled_runtime) { | |
178 if (virtual_time_) | |
179 return; | |
180 | |
181 base::TimeTicks throttled_runtime = | |
182 ThrottledRunTime(std::max(now, unthrottled_runtime)); | |
183 // If there is a pending call to PumpThrottledTasks and it's sooner than | |
184 // |unthrottled_runtime| then return. | |
185 if (!pending_pump_throttled_tasks_runtime_.is_null() && | |
186 throttled_runtime >= pending_pump_throttled_tasks_runtime_) { | |
187 return; | |
188 } | |
189 | |
190 pending_pump_throttled_tasks_runtime_ = throttled_runtime; | |
191 | |
192 pump_throttled_tasks_closure_.Cancel(); | |
193 | |
194 base::TimeDelta delay = pending_pump_throttled_tasks_runtime_ - now; | |
195 TRACE_EVENT1(tracing_category_, | |
196 "ThrottlingHelper::MaybeSchedulePumpThrottledTasksLocked", | |
197 "delay_till_next_pump_ms", delay.InMilliseconds()); | |
198 task_runner_->PostDelayedTask( | |
199 from_here, pump_throttled_tasks_closure_.callback(), delay); | |
200 } | |
201 | |
202 void ThrottlingHelper::EnableVirtualTime() { | |
203 virtual_time_ = true; | |
204 | |
205 pump_throttled_tasks_closure_.Cancel(); | |
206 | |
207 while (!throttled_queues_.empty()) { | |
208 TaskQueue* task_queue = throttled_queues_.begin()->first; | |
209 bool enabled = throttled_queues_.begin()->second.enabled; | |
210 | |
211 throttled_queues_.erase(throttled_queues_.begin()); | |
212 | |
213 task_queue->SetTimeDomain(renderer_scheduler_->GetVirtualTimeDomain()); | |
214 task_queue->SetPumpPolicy(TaskQueue::PumpPolicy::AUTO); | |
215 task_queue->SetQueueEnabled(enabled); | |
216 } | |
217 } | |
218 | |
219 } // namespace scheduler | |
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