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1 /* | |
2 * Copyright (C) 2006, 2008 Apple Inc. All rights reserved. | |
3 * Copyright (C) 2009 Google Inc. All rights reserved. | |
4 * | |
5 * Redistribution and use in source and binary forms, with or without | |
6 * modification, are permitted provided that the following conditions | |
7 * are met: | |
8 * 1. Redistributions of source code must retain the above copyright | |
9 * notice, this list of conditions and the following disclaimer. | |
10 * 2. Redistributions in binary form must reproduce the above copyright | |
11 * notice, this list of conditions and the following disclaimer in the | |
12 * documentation and/or other materials provided with the distribution. | |
13 * | |
14 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY | |
15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
17 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR | |
18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, | |
19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, | |
20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR | |
21 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY | |
22 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
25 */ | |
26 | |
27 #include "config.h" | |
28 #include "platform/ThreadTimers.h" | |
29 | |
30 #include "platform/PlatformThreadData.h" | |
31 #include "platform/SharedTimer.h" | |
32 #include "platform/Timer.h" | |
33 #include "platform/TraceEvent.h" | |
34 #include "platform/scheduler/Scheduler.h" | |
35 #include "wtf/CurrentTime.h" | |
36 #include "wtf/MainThread.h" | |
37 | |
38 namespace blink { | |
39 | |
40 // Fire timers for this length of time, and then quit to let the run loop proces s user input events. | |
41 // 100ms is about a perceptable delay in UI, so use a half of that as a threshol d. | |
42 // This is to prevent UI freeze when there are too many timers or machine perfor mance is low. | |
43 static const double maxDurationOfFiringTimers = 0.050; | |
44 | |
45 // Timers are created, started and fired on the same thread, and each thread has its own ThreadTimers | |
46 // copy to keep the heap and a set of currently firing timers. | |
47 | |
48 static PassOwnPtr<MainThreadSharedTimer> mainThreadSharedTimer() | |
49 { | |
50 return adoptPtr(new MainThreadSharedTimer); | |
51 } | |
52 | |
53 ThreadTimers::ThreadTimers() | |
54 : m_sharedTimer(0) | |
55 , m_firingTimers(false) | |
56 , m_pendingSharedTimerFireTime(0) | |
57 { | |
58 if (isMainThread()) | |
59 setSharedTimer(mainThreadSharedTimer()); | |
60 } | |
61 | |
62 // A worker thread may initialize SharedTimer after some timers are created. | |
63 // Also, SharedTimer can be replaced with 0 before all timers are destroyed. | |
64 void ThreadTimers::setSharedTimer(PassOwnPtr<SharedTimer> sharedTimer) | |
65 { | |
66 if (m_sharedTimer) { | |
67 m_sharedTimer->setFiredFunction(0); | |
68 m_sharedTimer->stop(); | |
69 m_pendingSharedTimerFireTime = 0; | |
70 } | |
71 | |
72 m_sharedTimer = sharedTimer; | |
73 | |
74 if (m_sharedTimer) { | |
75 m_sharedTimer->setFiredFunction(ThreadTimers::sharedTimerFired); | |
76 updateSharedTimer(); | |
77 } | |
78 } | |
79 | |
80 void ThreadTimers::updateSharedTimer() | |
81 { | |
82 if (!m_sharedTimer) | |
83 return; | |
84 | |
85 if (m_firingTimers || m_timerHeap.isEmpty()) { | |
86 m_pendingSharedTimerFireTime = 0; | |
87 m_sharedTimer->stop(); | |
88 } else { | |
89 double nextFireTime = m_timerHeap.first()->m_nextFireTime; | |
90 double currentMonotonicTime = monotonicallyIncreasingTime(); | |
91 if (m_pendingSharedTimerFireTime) { | |
92 // No need to restart the timer if both the pending fire time and th e new fire time are in the past. | |
93 if (m_pendingSharedTimerFireTime <= currentMonotonicTime && nextFire Time <= currentMonotonicTime) | |
94 return; | |
95 } | |
96 m_pendingSharedTimerFireTime = nextFireTime; | |
97 m_sharedTimer->setFireInterval(std::max(nextFireTime - currentMonotonicT ime, 0.0)); | |
98 } | |
99 } | |
100 | |
101 void ThreadTimers::sharedTimerFired() | |
102 { | |
103 TRACE_EVENT_SET_SAMPLING_STATE("blink", "BlinkInternal"); | |
Sami
2015/04/09 10:52:29
I assume this is for sampled trace events? Can we
alex clarke (OOO till 29th)
2015/04/10 15:29:34
Done.
| |
104 | |
105 // Redirect to non-static method. | |
106 PlatformThreadData::current().threadTimers().sharedTimerFiredInternal(); | |
107 | |
108 TRACE_EVENT_SET_SAMPLING_STATE("blink", "Sleeping"); | |
109 } | |
110 | |
111 void ThreadTimers::sharedTimerFiredInternal() | |
112 { | |
113 // Do a re-entrancy check. | |
114 if (m_firingTimers) | |
115 return; | |
116 m_firingTimers = true; | |
117 m_pendingSharedTimerFireTime = 0; | |
118 | |
119 double fireTime = monotonicallyIncreasingTime(); | |
120 double timeToQuit = fireTime + maxDurationOfFiringTimers; | |
121 | |
122 while (!m_timerHeap.isEmpty() && m_timerHeap.first()->m_nextFireTime <= fire Time) { | |
123 TimerBase& timer = *m_timerHeap.first(); | |
124 timer.m_nextFireTime = 0; | |
125 timer.m_unalignedNextFireTime = 0; | |
126 timer.heapDeleteMin(); | |
127 | |
128 double interval = timer.repeatInterval(); | |
129 timer.setNextFireTime(interval ? fireTime + interval : 0); | |
130 | |
131 TRACE_EVENT2("blink", "ThreadTimers::sharedTimerFiredInternal", | |
132 "src_file", timer.location().fileName(), | |
133 "src_func", timer.location().functionName()); | |
134 | |
135 // Once the timer has been fired, it may be deleted, so do nothing else with it after this point. | |
136 timer.fired(); | |
137 | |
138 // Catch the case where the timer asked timers to fire in a nested event loop, or we are over time limit. | |
139 if (!m_firingTimers || timeToQuit < monotonicallyIncreasingTime() || (is MainThread() && Scheduler::shared()->shouldYieldForHighPriorityWork())) | |
140 break; | |
141 } | |
142 | |
143 m_firingTimers = false; | |
144 | |
145 updateSharedTimer(); | |
146 } | |
147 | |
148 void ThreadTimers::fireTimersInNestedEventLoop() | |
149 { | |
150 // Reset the reentrancy guard so the timers can fire again. | |
151 m_firingTimers = false; | |
152 updateSharedTimer(); | |
153 } | |
154 | |
155 } // namespace blink | |
156 | |
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