From 6bf0a5cb5034a7e684dcc3500e841785237ce2dd Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 19:32:43 +0200 Subject: Adding upstream version 1:115.7.0. Signed-off-by: Daniel Baumann --- xpcom/threads/TimerThread.h | 243 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 243 insertions(+) create mode 100644 xpcom/threads/TimerThread.h (limited to 'xpcom/threads/TimerThread.h') diff --git a/xpcom/threads/TimerThread.h b/xpcom/threads/TimerThread.h new file mode 100644 index 0000000000..ec138efca6 --- /dev/null +++ b/xpcom/threads/TimerThread.h @@ -0,0 +1,243 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef TimerThread_h___ +#define TimerThread_h___ + +#include "nsIObserver.h" +#include "nsIRunnable.h" +#include "nsIThread.h" + +#include "nsTimerImpl.h" +#include "nsThreadUtils.h" + +#include "nsTArray.h" + +#include "mozilla/Atomics.h" +#include "mozilla/Attributes.h" +#include "mozilla/Monitor.h" +#include "mozilla/ProfilerUtils.h" +#include "mozilla/UniquePtr.h" + +#include + +namespace mozilla { +class TimeStamp; +} // namespace mozilla + +// Enable this to compute lots of interesting statistics and print them out when +// PrintStatistics() is called. +#define TIMER_THREAD_STATISTICS 0 + +class TimerThread final : public mozilla::Runnable, public nsIObserver { + public: + typedef mozilla::Monitor Monitor; + typedef mozilla::MutexAutoLock MutexAutoLock; + typedef mozilla::TimeStamp TimeStamp; + typedef mozilla::TimeDuration TimeDuration; + + TimerThread(); + + NS_DECL_ISUPPORTS_INHERITED + NS_DECL_NSIRUNNABLE + NS_DECL_NSIOBSERVER + + nsresult Shutdown(); + + nsresult AddTimer(nsTimerImpl* aTimer, const MutexAutoLock& aProofOfLock) + MOZ_REQUIRES(aTimer->mMutex); + nsresult RemoveTimer(nsTimerImpl* aTimer, const MutexAutoLock& aProofOfLock) + MOZ_REQUIRES(aTimer->mMutex); + // Considering only the first 'aSearchBound' timers (in firing order), returns + // the timeout of the first non-low-priority timer, on the current thread, + // that will fire before 'aDefault'. If no such timer exists, 'aDefault' is + // returned. + TimeStamp FindNextFireTimeForCurrentThread(TimeStamp aDefault, + uint32_t aSearchBound); + + void DoBeforeSleep(); + void DoAfterSleep(); + + bool IsOnTimerThread() const { return mThread->IsOnCurrentThread(); } + + uint32_t AllowedEarlyFiringMicroseconds(); + nsresult GetTimers(nsTArray>& aRetVal); + + private: + ~TimerThread(); + + bool mInitialized; + + // These internal helper methods must be called while mMonitor is held. + // AddTimerInternal returns false if the insertion failed. + bool AddTimerInternal(nsTimerImpl& aTimer) MOZ_REQUIRES(mMonitor); + bool RemoveTimerInternal(nsTimerImpl& aTimer) + MOZ_REQUIRES(mMonitor, aTimer.mMutex); + void RemoveLeadingCanceledTimersInternal() MOZ_REQUIRES(mMonitor); + void RemoveFirstTimerInternal() MOZ_REQUIRES(mMonitor); + nsresult Init() MOZ_REQUIRES(mMonitor); + + void PostTimerEvent(already_AddRefed aTimerRef) + MOZ_REQUIRES(mMonitor); + + nsCOMPtr mThread; + // Lock ordering requirements: + // (optional) ThreadWrapper::sMutex -> + // (optional) nsTimerImpl::mMutex -> + // TimerThread::mMonitor + Monitor mMonitor; + + bool mShutdown MOZ_GUARDED_BY(mMonitor); + bool mWaiting MOZ_GUARDED_BY(mMonitor); + bool mNotified MOZ_GUARDED_BY(mMonitor); + bool mSleeping MOZ_GUARDED_BY(mMonitor); + + class Entry final { + public: + explicit Entry(nsTimerImpl& aTimerImpl) + : mTimeout(aTimerImpl.mTimeout), + mDelay(aTimerImpl.mDelay), + mTimerImpl(&aTimerImpl) { + aTimerImpl.SetIsInTimerThread(true); + } + + // Create an already-canceled entry with the given timeout. + explicit Entry(TimeStamp aTimeout) + : mTimeout(std::move(aTimeout)), mTimerImpl(nullptr) {} + + // Don't allow copies, otherwise which one would manage `IsInTimerThread`? + Entry(const Entry&) = delete; + Entry& operator=(const Entry&) = delete; + + // Move-only. + Entry(Entry&&) = default; + Entry& operator=(Entry&&) = default; + + ~Entry() { + if (mTimerImpl) { + mTimerImpl->mMutex.AssertCurrentThreadOwns(); + mTimerImpl->SetIsInTimerThread(false); + } + } + + nsTimerImpl* Value() const { return mTimerImpl; } + + void Forget() { + if (MOZ_UNLIKELY(!mTimerImpl)) { + return; + } + mTimerImpl->mMutex.AssertCurrentThreadOwns(); + mTimerImpl->SetIsInTimerThread(false); + mTimerImpl = nullptr; + } + + // Called with the Monitor held, but not the TimerImpl's mutex + already_AddRefed Take() { + if (MOZ_LIKELY(mTimerImpl)) { + MOZ_ASSERT(mTimerImpl->IsInTimerThread()); + mTimerImpl->SetIsInTimerThread(false); + } + return mTimerImpl.forget(); + } + + const TimeStamp& Timeout() const { return mTimeout; } + const TimeDuration& Delay() const { return mDelay; } + + private: + // These values are simply cached from the timer. Keeping them here is good + // for cache usage and allows us to avoid worrying about locking conflicts + // with the timer. + TimeStamp mTimeout; + TimeDuration mDelay; + + RefPtr mTimerImpl; + }; + + // Computes and returns the index in mTimers at which a new timer with the + // specified timeout should be inserted in order to maintain "sorted" order. + size_t ComputeTimerInsertionIndex(const TimeStamp& timeout) const + MOZ_REQUIRES(mMonitor); + + // Computes and returns when we should next try to wake up in order to handle + // the triggering of the timers in mTimers. Currently this is very simple and + // we always just plan to wake up for the next timer in the list. In the + // future this will be more sophisticated. + TimeStamp ComputeWakeupTimeFromTimers() const MOZ_REQUIRES(mMonitor); + + // Computes how late a timer can acceptably fire. + // timerDuration is the duration of the timer whose delay we are calculating. + // Longer timers can tolerate longer firing delays. + // minDelay is an amount by which any timer can be delayed. + // This function will never return a value smaller than minDelay (unless this + // conflicts with maxDelay). maxDelay is the upper limit on the amount by + // which we will ever delay any timer. Takes precedence over minDelay if there + // is a conflict. (Zero will effectively disable timer coalescing.) + TimeDuration ComputeAcceptableFiringDelay(TimeDuration timerDuration, + TimeDuration minDelay, + TimeDuration maxDelay) const; + +#ifdef DEBUG + // Checks mTimers to see if any entries are out of order or any cached + // timeouts are incorrect and will assert if any inconsistency is found. Has + // no side effects other than asserting so has no use in non-DEBUG builds. + void VerifyTimerListConsistency() const MOZ_REQUIRES(mMonitor); +#endif + + // mTimers is maintained in a "pseudo-sorted" order wrt the timeouts. + // Specifcally, mTimers is sorted according to the timeouts *if you ignore the + // canceled entries* (those whose mTimerImpl is nullptr). Notably this means + // that you cannot use a binary search on this list. + nsTArray mTimers MOZ_GUARDED_BY(mMonitor); + + // Set only at the start of the thread's Run(): + uint32_t mAllowedEarlyFiringMicroseconds MOZ_GUARDED_BY(mMonitor); + + ProfilerThreadId mProfilerThreadId MOZ_GUARDED_BY(mMonitor); + + // Time at which we were intending to wake up the last time that we slept. + // Is "null" if we have never slept or if our last sleep was "forever". + TimeStamp mIntendedWakeupTime; + +#if TIMER_THREAD_STATISTICS + static constexpr size_t sTimersFiredPerWakeupBucketCount = 16; + static inline constexpr std::array + sTimersFiredPerWakeupThresholds = { + 0, 1, 2, 3, 4, 5, 6, 7, 8, 12, 20, 30, 40, 50, 70, (size_t)(-1)}; + + mutable AutoTArray + mTimersFiredPerWakeup MOZ_GUARDED_BY(mMonitor) = {0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0}; + mutable AutoTArray + mTimersFiredPerUnnotifiedWakeup MOZ_GUARDED_BY(mMonitor) = { + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}; + mutable AutoTArray + mTimersFiredPerNotifiedWakeup MOZ_GUARDED_BY(mMonitor) = { + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}; + + mutable size_t mTotalTimersAdded MOZ_GUARDED_BY(mMonitor) = 0; + mutable size_t mTotalTimersRemoved MOZ_GUARDED_BY(mMonitor) = 0; + mutable size_t mTotalTimersFiredNotified MOZ_GUARDED_BY(mMonitor) = 0; + mutable size_t mTotalTimersFiredUnnotified MOZ_GUARDED_BY(mMonitor) = 0; + + mutable size_t mTotalWakeupCount MOZ_GUARDED_BY(mMonitor) = 0; + mutable size_t mTotalUnnotifiedWakeupCount MOZ_GUARDED_BY(mMonitor) = 0; + mutable size_t mTotalNotifiedWakeupCount MOZ_GUARDED_BY(mMonitor) = 0; + + mutable double mTotalActualTimerFiringDelayNotified MOZ_GUARDED_BY(mMonitor) = + 0.0; + mutable double mTotalActualTimerFiringDelayUnnotified + MOZ_GUARDED_BY(mMonitor) = 0.0; + + mutable TimeStamp mFirstTimerAdded MOZ_GUARDED_BY(mMonitor); + + mutable size_t mEarlyWakeups MOZ_GUARDED_BY(mMonitor) = 0; + mutable double mTotalEarlyWakeupTime MOZ_GUARDED_BY(mMonitor) = 0.0; + + void PrintStatistics() const; +#endif +}; + +#endif /* TimerThread_h___ */ -- cgit v1.2.3