forked from mirrors/gecko-dev
bc62941a4a
- Prior to this change, we allowed any timer *except* the first to fire early. Being woken up slightly before our first timer is due was resulting in a lot of "wasted" wake-ups (where we wake up and do nothing other than go back to sleep). - This change results in waking up TimerThread 10% less frequently in my test case of watching a YouTube video. - Made the allowed early firing tolerance be a constant value rather than calculated at run-time. - Also cleaned up some includes. Differential Revision: https://phabricator.services.mozilla.com/D184017
1474 lines
51 KiB
C++
1474 lines
51 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "nsTimerImpl.h"
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#include "TimerThread.h"
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#include "GeckoProfiler.h"
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#include "nsThreadUtils.h"
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#include "nsIObserverService.h"
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#include "mozilla/Services.h"
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#include "mozilla/ChaosMode.h"
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#include "mozilla/ArenaAllocator.h"
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#include "mozilla/ArrayUtils.h"
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#include "mozilla/OperatorNewExtensions.h"
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#include "mozilla/StaticPrefs_timer.h"
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#include "mozilla/glean/GleanMetrics.h"
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#include <math.h>
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using namespace mozilla;
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// Uncomment the following line to enable runtime stats during development.
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// #define TIMERS_RUNTIME_STATS
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#ifdef TIMERS_RUNTIME_STATS
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// This class gathers durations and displays some basic stats when destroyed.
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// It is intended to be used as a static variable (see `AUTO_TIMERS_STATS`
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// below), to display stats at the end of the program.
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class StaticTimersStats {
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public:
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explicit StaticTimersStats(const char* aName) : mName(aName) {}
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~StaticTimersStats() {
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// Using unsigned long long for computations and printfs.
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using ULL = unsigned long long;
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ULL n = static_cast<ULL>(mCount);
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if (n == 0) {
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printf("[%d] Timers stats `%s`: (nothing)\n",
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int(profiler_current_process_id().ToNumber()), mName);
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} else if (ULL sumNs = static_cast<ULL>(mSumDurationsNs); sumNs == 0) {
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printf("[%d] Timers stats `%s`: %llu\n",
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int(profiler_current_process_id().ToNumber()), mName, n);
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} else {
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printf("[%d] Timers stats `%s`: %llu ns / %llu = %llu ns, max %llu ns\n",
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int(profiler_current_process_id().ToNumber()), mName, sumNs, n,
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sumNs / n, static_cast<ULL>(mLongestDurationNs));
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}
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}
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void AddDurationFrom(TimeStamp aStart) {
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// Duration between aStart and now, rounded to the nearest nanosecond.
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DurationNs duration = static_cast<DurationNs>(
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(TimeStamp::Now() - aStart).ToMicroseconds() * 1000 + 0.5);
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mSumDurationsNs += duration;
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++mCount;
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// Update mLongestDurationNs if this one is longer.
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for (;;) {
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DurationNs longest = mLongestDurationNs;
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if (MOZ_LIKELY(longest >= duration)) {
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// This duration is not the longest, nothing to do.
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break;
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}
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if (MOZ_LIKELY(mLongestDurationNs.compareExchange(longest, duration))) {
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// Successfully updated `mLongestDurationNs` with the new value.
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break;
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}
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// Otherwise someone else just updated `mLongestDurationNs`, we need to
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// try again by looping.
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}
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}
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void AddCount() {
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MOZ_ASSERT(mSumDurationsNs == 0, "Don't mix counts and durations");
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++mCount;
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}
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private:
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using DurationNs = uint64_t;
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using Count = uint32_t;
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Atomic<DurationNs> mSumDurationsNs{0};
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Atomic<DurationNs> mLongestDurationNs{0};
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Atomic<Count> mCount{0};
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const char* mName;
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};
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// RAII object that measures its scoped lifetime duration and reports it to a
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// `StaticTimersStats`.
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class MOZ_RAII AutoTimersStats {
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public:
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explicit AutoTimersStats(StaticTimersStats& aStats)
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: mStats(aStats), mStart(TimeStamp::Now()) {}
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~AutoTimersStats() { mStats.AddDurationFrom(mStart); }
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private:
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StaticTimersStats& mStats;
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TimeStamp mStart;
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};
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// Macro that should be used to collect basic statistics from measurements of
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// block durations, from where this macro is, until the end of its enclosing
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// scope. The name is used in the static variable name and when displaying stats
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// at the end of the program; Another location could use the same name but their
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// stats will not be combined, so use different name if these locations should
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// be distinguished.
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# define AUTO_TIMERS_STATS(name) \
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static ::StaticTimersStats sStat##name(#name); \
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::AutoTimersStats autoStat##name(sStat##name);
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// This macro only counts the number of times it's used, not durations.
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// Don't mix with AUTO_TIMERS_STATS!
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# define COUNT_TIMERS_STATS(name) \
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static ::StaticTimersStats sStat##name(#name); \
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sStat##name.AddCount();
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#else // TIMERS_RUNTIME_STATS
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# define AUTO_TIMERS_STATS(name)
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# define COUNT_TIMERS_STATS(name)
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#endif // TIMERS_RUNTIME_STATS else
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NS_IMPL_ISUPPORTS_INHERITED(TimerThread, Runnable, nsIObserver)
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TimerThread::TimerThread()
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: Runnable("TimerThread"),
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mInitialized(false),
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mMonitor("TimerThread.mMonitor"),
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mShutdown(false),
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mWaiting(false),
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mNotified(false),
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mSleeping(false),
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mAllowedEarlyFiringMicroseconds(0) {}
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TimerThread::~TimerThread() {
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mThread = nullptr;
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NS_ASSERTION(mTimers.IsEmpty(), "Timers remain in TimerThread::~TimerThread");
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#if TIMER_THREAD_STATISTICS
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{
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MonitorAutoLock lock(mMonitor);
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PrintStatistics();
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}
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#endif
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}
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namespace {
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class TimerObserverRunnable : public Runnable {
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public:
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explicit TimerObserverRunnable(nsIObserver* aObserver)
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: mozilla::Runnable("TimerObserverRunnable"), mObserver(aObserver) {}
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NS_DECL_NSIRUNNABLE
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private:
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nsCOMPtr<nsIObserver> mObserver;
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};
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NS_IMETHODIMP
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TimerObserverRunnable::Run() {
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nsCOMPtr<nsIObserverService> observerService =
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mozilla::services::GetObserverService();
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if (observerService) {
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observerService->AddObserver(mObserver, "sleep_notification", false);
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observerService->AddObserver(mObserver, "wake_notification", false);
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observerService->AddObserver(mObserver, "suspend_process_notification",
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false);
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observerService->AddObserver(mObserver, "resume_process_notification",
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false);
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}
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return NS_OK;
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}
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} // namespace
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namespace {
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// TimerEventAllocator is a thread-safe allocator used only for nsTimerEvents.
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// It's needed to avoid contention over the default allocator lock when
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// firing timer events (see bug 733277). The thread-safety is required because
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// nsTimerEvent objects are allocated on the timer thread, and freed on another
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// thread. Because TimerEventAllocator has its own lock, contention over that
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// lock is limited to the allocation and deallocation of nsTimerEvent objects.
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//
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// Because this is layered over ArenaAllocator, it never shrinks -- even
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// "freed" nsTimerEvents aren't truly freed, they're just put onto a free-list
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// for later recycling. So the amount of memory consumed will always be equal
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// to the high-water mark consumption. But nsTimerEvents are small and it's
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// unusual to have more than a few hundred of them, so this shouldn't be a
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// problem in practice.
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class TimerEventAllocator {
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private:
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struct FreeEntry {
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FreeEntry* mNext;
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};
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ArenaAllocator<4096> mPool MOZ_GUARDED_BY(mMonitor);
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FreeEntry* mFirstFree MOZ_GUARDED_BY(mMonitor);
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mozilla::Monitor mMonitor;
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public:
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TimerEventAllocator()
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: mPool(), mFirstFree(nullptr), mMonitor("TimerEventAllocator") {}
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~TimerEventAllocator() = default;
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void* Alloc(size_t aSize);
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void Free(void* aPtr);
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};
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} // namespace
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// This is a nsICancelableRunnable because we can dispatch it to Workers and
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// those can be shut down at any time, and in these cases, Cancel() is called
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// instead of Run().
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class nsTimerEvent final : public CancelableRunnable {
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public:
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NS_IMETHOD Run() override;
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nsresult Cancel() override {
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mTimer->Cancel();
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return NS_OK;
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}
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#ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
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NS_IMETHOD GetName(nsACString& aName) override;
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#endif
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explicit nsTimerEvent(already_AddRefed<nsTimerImpl> aTimer,
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ProfilerThreadId aTimerThreadId)
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: mozilla::CancelableRunnable("nsTimerEvent"),
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mTimer(aTimer),
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mGeneration(mTimer->GetGeneration()),
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mTimerThreadId(aTimerThreadId) {
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// Note: We override operator new for this class, and the override is
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// fallible!
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sAllocatorUsers++;
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if (MOZ_LOG_TEST(GetTimerLog(), LogLevel::Debug) ||
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profiler_thread_is_being_profiled_for_markers(mTimerThreadId)) {
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mInitTime = TimeStamp::Now();
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}
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}
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static void Init();
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static void Shutdown();
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static void DeleteAllocatorIfNeeded();
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static void* operator new(size_t aSize) noexcept(true) {
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return sAllocator->Alloc(aSize);
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}
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void operator delete(void* aPtr) {
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sAllocator->Free(aPtr);
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sAllocatorUsers--;
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DeleteAllocatorIfNeeded();
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}
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already_AddRefed<nsTimerImpl> ForgetTimer() { return mTimer.forget(); }
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private:
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nsTimerEvent(const nsTimerEvent&) = delete;
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nsTimerEvent& operator=(const nsTimerEvent&) = delete;
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nsTimerEvent& operator=(const nsTimerEvent&&) = delete;
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~nsTimerEvent() {
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MOZ_ASSERT(!sCanDeleteAllocator || sAllocatorUsers > 0,
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"This will result in us attempting to deallocate the "
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"nsTimerEvent allocator twice");
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}
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TimeStamp mInitTime;
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RefPtr<nsTimerImpl> mTimer;
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const int32_t mGeneration;
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ProfilerThreadId mTimerThreadId;
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static TimerEventAllocator* sAllocator;
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static Atomic<int32_t, SequentiallyConsistent> sAllocatorUsers;
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static Atomic<bool, SequentiallyConsistent> sCanDeleteAllocator;
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};
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TimerEventAllocator* nsTimerEvent::sAllocator = nullptr;
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Atomic<int32_t, SequentiallyConsistent> nsTimerEvent::sAllocatorUsers;
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Atomic<bool, SequentiallyConsistent> nsTimerEvent::sCanDeleteAllocator;
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namespace {
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void* TimerEventAllocator::Alloc(size_t aSize) {
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MOZ_ASSERT(aSize == sizeof(nsTimerEvent));
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mozilla::MonitorAutoLock lock(mMonitor);
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void* p;
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if (mFirstFree) {
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p = mFirstFree;
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mFirstFree = mFirstFree->mNext;
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} else {
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p = mPool.Allocate(aSize, fallible);
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}
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return p;
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}
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void TimerEventAllocator::Free(void* aPtr) {
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mozilla::MonitorAutoLock lock(mMonitor);
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FreeEntry* entry = reinterpret_cast<FreeEntry*>(aPtr);
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entry->mNext = mFirstFree;
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mFirstFree = entry;
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}
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} // namespace
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struct TimerMarker {
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static constexpr Span<const char> MarkerTypeName() {
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return MakeStringSpan("Timer");
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}
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static void StreamJSONMarkerData(baseprofiler::SpliceableJSONWriter& aWriter,
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uint32_t aDelay, uint8_t aType,
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MarkerThreadId aThreadId, bool aCanceled) {
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aWriter.IntProperty("delay", aDelay);
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if (!aThreadId.IsUnspecified()) {
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// Tech note: If `ToNumber()` returns a uint64_t, the conversion to
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// int64_t is "implementation-defined" before C++20. This is
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// acceptable here, because this is a one-way conversion to a unique
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// identifier that's used to visually separate data by thread on the
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// front-end.
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aWriter.IntProperty(
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"threadId", static_cast<int64_t>(aThreadId.ThreadId().ToNumber()));
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}
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if (aCanceled) {
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aWriter.BoolProperty("canceled", true);
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// Show a red 'X' as a prefix on the marker chart for canceled timers.
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aWriter.StringProperty("prefix", "❌");
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}
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// The string property for the timer type is not written when the type is
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// one shot, as that's the type used almost all the time, and that would
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// consume space in the profiler buffer and then in the profile JSON,
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// getting in the way of capturing long power profiles.
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// Bug 1815677 might make this cheap to capture.
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if (aType != nsITimer::TYPE_ONE_SHOT) {
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if (aType == nsITimer::TYPE_REPEATING_SLACK) {
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aWriter.StringProperty("ttype", "repeating slack");
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} else if (aType == nsITimer::TYPE_REPEATING_PRECISE) {
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aWriter.StringProperty("ttype", "repeating precise");
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} else if (aType == nsITimer::TYPE_REPEATING_PRECISE_CAN_SKIP) {
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aWriter.StringProperty("ttype", "repeating precise can skip");
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} else if (aType == nsITimer::TYPE_REPEATING_SLACK_LOW_PRIORITY) {
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aWriter.StringProperty("ttype", "repeating slack low priority");
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} else if (aType == nsITimer::TYPE_ONE_SHOT_LOW_PRIORITY) {
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aWriter.StringProperty("ttype", "low priority");
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}
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}
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}
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static MarkerSchema MarkerTypeDisplay() {
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using MS = MarkerSchema;
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MS schema{MS::Location::MarkerChart, MS::Location::MarkerTable};
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schema.AddKeyLabelFormat("delay", "Delay", MS::Format::Milliseconds);
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schema.AddKeyLabelFormat("ttype", "Timer Type", MS::Format::String);
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schema.AddKeyLabelFormat("canceled", "Canceled", MS::Format::String);
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schema.SetChartLabel("{marker.data.prefix} {marker.data.delay}");
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schema.SetTableLabel(
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"{marker.name} - {marker.data.prefix} {marker.data.delay}");
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return schema;
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}
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};
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struct AddRemoveTimerMarker {
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static constexpr Span<const char> MarkerTypeName() {
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return MakeStringSpan("AddRemoveTimer");
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}
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static void StreamJSONMarkerData(baseprofiler::SpliceableJSONWriter& aWriter,
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const ProfilerString8View& aTimerName,
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uint32_t aDelay, MarkerThreadId aThreadId) {
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aWriter.StringProperty("name", aTimerName);
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aWriter.IntProperty("delay", aDelay);
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if (!aThreadId.IsUnspecified()) {
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// Tech note: If `ToNumber()` returns a uint64_t, the conversion to
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// int64_t is "implementation-defined" before C++20. This is
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// acceptable here, because this is a one-way conversion to a unique
|
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// identifier that's used to visually separate data by thread on the
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// front-end.
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aWriter.IntProperty(
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"threadId", static_cast<int64_t>(aThreadId.ThreadId().ToNumber()));
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}
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}
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static MarkerSchema MarkerTypeDisplay() {
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using MS = MarkerSchema;
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MS schema{MS::Location::MarkerChart, MS::Location::MarkerTable};
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schema.AddKeyLabelFormatSearchable("name", "Name", MS::Format::String,
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MS::Searchable::Searchable);
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schema.AddKeyLabelFormat("delay", "Delay", MS::Format::Milliseconds);
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schema.SetTableLabel(
|
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"{marker.name} - {marker.data.name} - {marker.data.delay}");
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return schema;
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}
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};
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void nsTimerEvent::Init() { sAllocator = new TimerEventAllocator(); }
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void nsTimerEvent::Shutdown() {
|
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sCanDeleteAllocator = true;
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DeleteAllocatorIfNeeded();
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}
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|
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void nsTimerEvent::DeleteAllocatorIfNeeded() {
|
|
if (sCanDeleteAllocator && sAllocatorUsers == 0) {
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delete sAllocator;
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sAllocator = nullptr;
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}
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}
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#ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
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NS_IMETHODIMP
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nsTimerEvent::GetName(nsACString& aName) {
|
|
bool current;
|
|
MOZ_RELEASE_ASSERT(
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|
NS_SUCCEEDED(mTimer->mEventTarget->IsOnCurrentThread(¤t)) &&
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current);
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|
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mTimer->GetName(aName);
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return NS_OK;
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|
}
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|
#endif
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NS_IMETHODIMP
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|
nsTimerEvent::Run() {
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|
if (MOZ_LOG_TEST(GetTimerLog(), LogLevel::Debug)) {
|
|
TimeStamp now = TimeStamp::Now();
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MOZ_LOG(GetTimerLog(), LogLevel::Debug,
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|
("[this=%p] time between PostTimerEvent() and Fire(): %fms\n", this,
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(now - mInitTime).ToMilliseconds()));
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|
}
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|
|
if (profiler_thread_is_being_profiled_for_markers(mTimerThreadId)) {
|
|
MutexAutoLock lock(mTimer->mMutex);
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|
nsAutoCString name;
|
|
mTimer->GetName(name, lock);
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|
// This adds a marker with the timer name as the marker name, to make it
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|
// obvious which timers are being used. This marker will be useful to
|
|
// understand which timers might be added and firing excessively often.
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|
profiler_add_marker(
|
|
name, geckoprofiler::category::TIMER,
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MarkerOptions(MOZ_LIKELY(mInitTime)
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|
? MarkerTiming::Interval(
|
|
mTimer->mTimeout - mTimer->mDelay, mInitTime)
|
|
: MarkerTiming::IntervalUntilNowFrom(
|
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mTimer->mTimeout - mTimer->mDelay),
|
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MarkerThreadId(mTimerThreadId)),
|
|
TimerMarker{}, mTimer->mDelay.ToMilliseconds(), mTimer->mType,
|
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MarkerThreadId::CurrentThread(), false);
|
|
// This marker is meant to help understand the behavior of the timer thread.
|
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profiler_add_marker(
|
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"PostTimerEvent", geckoprofiler::category::OTHER,
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MarkerOptions(MOZ_LIKELY(mInitTime)
|
|
? MarkerTiming::IntervalUntilNowFrom(mInitTime)
|
|
: MarkerTiming::InstantNow(),
|
|
MarkerThreadId(mTimerThreadId)),
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|
AddRemoveTimerMarker{}, name, mTimer->mDelay.ToMilliseconds(),
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MarkerThreadId::CurrentThread());
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}
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|
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mTimer->Fire(mGeneration);
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|
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return NS_OK;
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}
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|
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nsresult TimerThread::Init() {
|
|
mMonitor.AssertCurrentThreadOwns();
|
|
MOZ_LOG(GetTimerLog(), LogLevel::Debug,
|
|
("TimerThread::Init [%d]\n", mInitialized));
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|
|
|
if (!mInitialized) {
|
|
nsTimerEvent::Init();
|
|
|
|
// We hold on to mThread to keep the thread alive.
|
|
nsresult rv =
|
|
NS_NewNamedThread("Timer", getter_AddRefs(mThread), this,
|
|
{.stackSize = nsIThreadManager::DEFAULT_STACK_SIZE,
|
|
.blockDispatch = true});
|
|
if (NS_FAILED(rv)) {
|
|
mThread = nullptr;
|
|
} else {
|
|
RefPtr<TimerObserverRunnable> r = new TimerObserverRunnable(this);
|
|
if (NS_IsMainThread()) {
|
|
r->Run();
|
|
} else {
|
|
NS_DispatchToMainThread(r);
|
|
}
|
|
}
|
|
|
|
mInitialized = true;
|
|
}
|
|
|
|
if (!mThread) {
|
|
return NS_ERROR_FAILURE;
|
|
}
|
|
|
|
return NS_OK;
|
|
}
|
|
|
|
nsresult TimerThread::Shutdown() {
|
|
MOZ_LOG(GetTimerLog(), LogLevel::Debug, ("TimerThread::Shutdown begin\n"));
|
|
|
|
if (!mThread) {
|
|
return NS_ERROR_NOT_INITIALIZED;
|
|
}
|
|
|
|
nsTArray<RefPtr<nsTimerImpl>> timers;
|
|
{
|
|
// lock scope
|
|
MonitorAutoLock lock(mMonitor);
|
|
|
|
mShutdown = true;
|
|
|
|
// notify the cond var so that Run() can return
|
|
if (mWaiting) {
|
|
mNotified = true;
|
|
mMonitor.Notify();
|
|
}
|
|
|
|
// Need to copy content of mTimers array to a local array
|
|
// because call to timers' Cancel() (and release its self)
|
|
// must not be done under the lock. Destructor of a callback
|
|
// might potentially call some code reentering the same lock
|
|
// that leads to unexpected behavior or deadlock.
|
|
// See bug 422472.
|
|
timers.SetCapacity(mTimers.Length());
|
|
for (Entry& entry : mTimers) {
|
|
if (entry.Value()) {
|
|
timers.AppendElement(entry.Take());
|
|
}
|
|
}
|
|
|
|
mTimers.Clear();
|
|
}
|
|
|
|
for (const RefPtr<nsTimerImpl>& timer : timers) {
|
|
MOZ_ASSERT(timer);
|
|
timer->Cancel();
|
|
}
|
|
|
|
mThread->Shutdown(); // wait for the thread to die
|
|
|
|
nsTimerEvent::Shutdown();
|
|
|
|
MOZ_LOG(GetTimerLog(), LogLevel::Debug, ("TimerThread::Shutdown end\n"));
|
|
return NS_OK;
|
|
}
|
|
|
|
namespace {
|
|
|
|
struct MicrosecondsToInterval {
|
|
PRIntervalTime operator[](size_t aMs) const {
|
|
return PR_MicrosecondsToInterval(aMs);
|
|
}
|
|
};
|
|
|
|
struct IntervalComparator {
|
|
int operator()(PRIntervalTime aInterval) const {
|
|
return (0 < aInterval) ? -1 : 1;
|
|
}
|
|
};
|
|
|
|
} // namespace
|
|
|
|
#ifdef DEBUG
|
|
void TimerThread::VerifyTimerListConsistency() const {
|
|
mMonitor.AssertCurrentThreadOwns();
|
|
|
|
// Find the first non-canceled timer (and check its cached timeout if we find
|
|
// it).
|
|
const size_t timerCount = mTimers.Length();
|
|
size_t lastNonCanceledTimerIndex = 0;
|
|
while (lastNonCanceledTimerIndex < timerCount &&
|
|
!mTimers[lastNonCanceledTimerIndex].Value()) {
|
|
++lastNonCanceledTimerIndex;
|
|
}
|
|
MOZ_ASSERT(lastNonCanceledTimerIndex == timerCount ||
|
|
mTimers[lastNonCanceledTimerIndex].Value());
|
|
MOZ_ASSERT(lastNonCanceledTimerIndex == timerCount ||
|
|
mTimers[lastNonCanceledTimerIndex].Value()->mTimeout ==
|
|
mTimers[lastNonCanceledTimerIndex].Timeout());
|
|
|
|
// Verify that mTimers is sorted and the cached timeouts are consistent.
|
|
for (size_t timerIndex = lastNonCanceledTimerIndex + 1;
|
|
timerIndex < timerCount; ++timerIndex) {
|
|
if (mTimers[timerIndex].Value()) {
|
|
MOZ_ASSERT(mTimers[timerIndex].Timeout() ==
|
|
mTimers[timerIndex].Value()->mTimeout);
|
|
MOZ_ASSERT(mTimers[timerIndex].Timeout() >=
|
|
mTimers[lastNonCanceledTimerIndex].Timeout());
|
|
lastNonCanceledTimerIndex = timerIndex;
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
size_t TimerThread::ComputeTimerInsertionIndex(const TimeStamp& timeout) const {
|
|
mMonitor.AssertCurrentThreadOwns();
|
|
|
|
const size_t timerCount = mTimers.Length();
|
|
|
|
size_t firstGtIndex = 0;
|
|
while (firstGtIndex < timerCount &&
|
|
(!mTimers[firstGtIndex].Value() ||
|
|
mTimers[firstGtIndex].Timeout() <= timeout)) {
|
|
++firstGtIndex;
|
|
}
|
|
|
|
return firstGtIndex;
|
|
}
|
|
|
|
TimeStamp TimerThread::ComputeWakeupTimeFromTimers() const {
|
|
mMonitor.AssertCurrentThreadOwns();
|
|
|
|
// Timer list should be non-empty and first timer should always be
|
|
// non-canceled at this point and we rely on that here.
|
|
MOZ_ASSERT(!mTimers.IsEmpty());
|
|
MOZ_ASSERT(mTimers[0].Value());
|
|
|
|
// Overview: Find the last timer in the list that can be "bundled" together in
|
|
// the same wake-up with mTimers[0] and use its timeout as our target wake-up
|
|
// time.
|
|
|
|
// bundleWakeup is when we should wake up in order to be able to fire all of
|
|
// the timers in our selected bundle. It will always be the timeout of the
|
|
// last timer in the bundle.
|
|
TimeStamp bundleWakeup = mTimers[0].Timeout();
|
|
|
|
// cutoffTime is the latest that we can wake up for the timers currently
|
|
// accepted into the bundle. These needs to be updated as we go through the
|
|
// list because later timers may have more strict delay tolerances.
|
|
const TimeDuration minTimerDelay = TimeDuration::FromMilliseconds(
|
|
StaticPrefs::timer_minimum_firing_delay_tolerance_ms());
|
|
const TimeDuration maxTimerDelay = TimeDuration::FromMilliseconds(
|
|
StaticPrefs::timer_maximum_firing_delay_tolerance_ms());
|
|
TimeStamp cutoffTime =
|
|
bundleWakeup + ComputeAcceptableFiringDelay(mTimers[0].Delay(),
|
|
minTimerDelay, maxTimerDelay);
|
|
|
|
const size_t timerCount = mTimers.Length();
|
|
for (size_t entryIndex = 1; entryIndex < timerCount; ++entryIndex) {
|
|
const Entry& curEntry = mTimers[entryIndex];
|
|
const nsTimerImpl* curTimer = curEntry.Value();
|
|
if (!curTimer) {
|
|
// Canceled timer - skip it
|
|
continue;
|
|
}
|
|
|
|
const TimeStamp curTimerDue = curEntry.Timeout();
|
|
if (curTimerDue > cutoffTime) {
|
|
// Can't include this timer in the bundle - it fires too late.
|
|
break;
|
|
}
|
|
|
|
// This timer can be included in the bundle. Update bundleWakeup and
|
|
// cutoffTime.
|
|
bundleWakeup = curTimerDue;
|
|
cutoffTime = std::min(
|
|
curTimerDue + ComputeAcceptableFiringDelay(
|
|
curEntry.Delay(), minTimerDelay, maxTimerDelay),
|
|
cutoffTime);
|
|
MOZ_ASSERT(bundleWakeup <= cutoffTime);
|
|
}
|
|
|
|
#if !defined(XP_WIN)
|
|
// Due to the fact that, on Windows, each TimeStamp object holds two distinct
|
|
// "values", this assert is not valid there. See bug 1829983 for the details.
|
|
MOZ_ASSERT(bundleWakeup - mTimers[0].Timeout() <=
|
|
ComputeAcceptableFiringDelay(mTimers[0].Delay(), minTimerDelay,
|
|
maxTimerDelay));
|
|
#endif
|
|
|
|
return bundleWakeup;
|
|
}
|
|
|
|
TimeDuration TimerThread::ComputeAcceptableFiringDelay(
|
|
TimeDuration timerDuration, TimeDuration minDelay,
|
|
TimeDuration maxDelay) const {
|
|
// Use the timer's duration divided by this value as a base for how much
|
|
// firing delay a timer can accept. 8 was chosen specifically because it is a
|
|
// power of two which means that this division turns nicely into a shift.
|
|
constexpr int64_t timerDurationDivider = 8;
|
|
static_assert(IsPowerOfTwo(static_cast<uint64_t>(timerDurationDivider)));
|
|
const TimeDuration tmp = timerDuration / timerDurationDivider;
|
|
return std::min(std::max(minDelay, tmp), maxDelay);
|
|
}
|
|
|
|
NS_IMETHODIMP
|
|
TimerThread::Run() {
|
|
MonitorAutoLock lock(mMonitor);
|
|
|
|
mProfilerThreadId = profiler_current_thread_id();
|
|
|
|
// TODO: Make mAllowedEarlyFiringMicroseconds const and initialize it in the
|
|
// constructor.
|
|
mAllowedEarlyFiringMicroseconds = 250;
|
|
const TimeDuration allowedEarlyFiring =
|
|
TimeDuration::FromMicroseconds(mAllowedEarlyFiringMicroseconds);
|
|
|
|
bool forceRunNextTimer = false;
|
|
|
|
// Queue for tracking of how many timers are fired on each wake-up. We need to
|
|
// buffer these locally and only send off to glean occasionally to avoid
|
|
// performance hit.
|
|
static constexpr size_t kMaxQueuedTimerFired = 128;
|
|
size_t queuedTimerFiredCount = 0;
|
|
AutoTArray<uint64_t, kMaxQueuedTimerFired> queuedTimersFiredPerWakeup;
|
|
queuedTimersFiredPerWakeup.SetLengthAndRetainStorage(kMaxQueuedTimerFired);
|
|
|
|
uint64_t timersFiredThisWakeup = 0;
|
|
while (!mShutdown) {
|
|
// Have to use PRIntervalTime here, since PR_WaitCondVar takes it
|
|
TimeDuration waitFor;
|
|
bool forceRunThisTimer = forceRunNextTimer;
|
|
forceRunNextTimer = false;
|
|
|
|
#ifdef DEBUG
|
|
VerifyTimerListConsistency();
|
|
#endif
|
|
|
|
if (mSleeping) {
|
|
// Sleep for 0.1 seconds while not firing timers.
|
|
uint32_t milliseconds = 100;
|
|
if (ChaosMode::isActive(ChaosFeature::TimerScheduling)) {
|
|
milliseconds = ChaosMode::randomUint32LessThan(200);
|
|
}
|
|
waitFor = TimeDuration::FromMilliseconds(milliseconds);
|
|
} else {
|
|
waitFor = TimeDuration::Forever();
|
|
TimeStamp now = TimeStamp::Now();
|
|
|
|
#if TIMER_THREAD_STATISTICS
|
|
if (!mNotified && !mIntendedWakeupTime.IsNull() &&
|
|
now < mIntendedWakeupTime) {
|
|
++mEarlyWakeups;
|
|
const double earlinessms = (mIntendedWakeupTime - now).ToMilliseconds();
|
|
mTotalEarlyWakeupTime += earlinessms;
|
|
}
|
|
#endif
|
|
|
|
RemoveLeadingCanceledTimersInternal();
|
|
|
|
if (!mTimers.IsEmpty()) {
|
|
if (now + allowedEarlyFiring >= mTimers[0].Value()->mTimeout ||
|
|
forceRunThisTimer) {
|
|
next:
|
|
// NB: AddRef before the Release under RemoveTimerInternal to avoid
|
|
// mRefCnt passing through zero, in case all other refs than the one
|
|
// from mTimers have gone away (the last non-mTimers[i]-ref's Release
|
|
// must be racing with us, blocked in gThread->RemoveTimer waiting
|
|
// for TimerThread::mMonitor, under nsTimerImpl::Release.
|
|
|
|
RefPtr<nsTimerImpl> timerRef(mTimers[0].Take());
|
|
RemoveFirstTimerInternal();
|
|
MOZ_LOG(GetTimerLog(), LogLevel::Debug,
|
|
("Timer thread woke up %fms from when it was supposed to\n",
|
|
fabs((now - timerRef->mTimeout).ToMilliseconds())));
|
|
|
|
// We are going to let the call to PostTimerEvent here handle the
|
|
// release of the timer so that we don't end up releasing the timer
|
|
// on the TimerThread instead of on the thread it targets.
|
|
{
|
|
++timersFiredThisWakeup;
|
|
LogTimerEvent::Run run(timerRef.get());
|
|
PostTimerEvent(timerRef.forget());
|
|
}
|
|
|
|
if (mShutdown) {
|
|
break;
|
|
}
|
|
|
|
// Update now, as PostTimerEvent plus the locking may have taken a
|
|
// tick or two, and we may goto next below.
|
|
now = TimeStamp::Now();
|
|
}
|
|
}
|
|
|
|
RemoveLeadingCanceledTimersInternal();
|
|
|
|
if (!mTimers.IsEmpty()) {
|
|
TimeStamp timeout = mTimers[0].Value()->mTimeout;
|
|
|
|
// Don't wait at all (even for PR_INTERVAL_NO_WAIT) if the next timer
|
|
// is due now or overdue.
|
|
//
|
|
// Note that we can only sleep for integer values of a certain
|
|
// resolution. We use mAllowedEarlyFiringMicroseconds, calculated
|
|
// before, to do the optimal rounding (i.e., of how to decide what
|
|
// interval is so small we should not wait at all).
|
|
double microseconds = (timeout - now).ToMicroseconds();
|
|
|
|
// The mean value of sFractions must be 1 to ensure that the average of
|
|
// a long sequence of timeouts converges to the actual sum of their
|
|
// times.
|
|
static constexpr double sChaosFractions[] = {0.0, 0.25, 0.5, 0.75,
|
|
1.0, 1.75, 2.75};
|
|
if (ChaosMode::isActive(ChaosFeature::TimerScheduling)) {
|
|
microseconds *= sChaosFractions[ChaosMode::randomUint32LessThan(
|
|
ArrayLength(sChaosFractions))];
|
|
forceRunNextTimer = true;
|
|
}
|
|
|
|
if (microseconds < mAllowedEarlyFiringMicroseconds) {
|
|
forceRunNextTimer = false;
|
|
goto next; // round down; execute event now
|
|
}
|
|
|
|
// TECHNICAL NOTE: Determining waitFor (by subtracting |now| from our
|
|
// desired wake-up time) at this point is not ideal. For one thing, the
|
|
// |now| that we have at this point is somewhat old. Secondly, there is
|
|
// quite a bit of code between here and where we actually use waitFor to
|
|
// request sleep. If I am thinking about this correctly, both of these
|
|
// will contribute to us requesting more sleep than is actually needed
|
|
// to wake up at our desired time. We could avoid this problem by only
|
|
// determining our desired wake-up time here and then calculating the
|
|
// wait time when we're actually about to sleep.
|
|
const TimeStamp wakeupTime = ComputeWakeupTimeFromTimers();
|
|
waitFor = wakeupTime - now;
|
|
|
|
// If this were to fail that would mean that we had more timers that we
|
|
// should have fired.
|
|
MOZ_ASSERT(!waitFor.IsZero());
|
|
|
|
if (ChaosMode::isActive(ChaosFeature::TimerScheduling)) {
|
|
// If chaos mode is active then mess with the amount of time that we
|
|
// request to sleep (without changing what we record as our expected
|
|
// wake-up time). This will simulate unintended early/late wake-ups.
|
|
const double waitInMs = waitFor.ToMilliseconds();
|
|
const double chaosWaitInMs =
|
|
waitInMs * sChaosFractions[ChaosMode::randomUint32LessThan(
|
|
ArrayLength(sChaosFractions))];
|
|
waitFor = TimeDuration::FromMilliseconds(chaosWaitInMs);
|
|
}
|
|
|
|
mIntendedWakeupTime = wakeupTime;
|
|
} else {
|
|
mIntendedWakeupTime = TimeStamp{};
|
|
}
|
|
|
|
if (MOZ_LOG_TEST(GetTimerLog(), LogLevel::Debug)) {
|
|
if (waitFor == TimeDuration::Forever())
|
|
MOZ_LOG(GetTimerLog(), LogLevel::Debug, ("waiting forever\n"));
|
|
else
|
|
MOZ_LOG(GetTimerLog(), LogLevel::Debug,
|
|
("waiting for %f\n", waitFor.ToMilliseconds()));
|
|
}
|
|
}
|
|
|
|
{
|
|
// About to sleep - let's make note of how many timers we processed and
|
|
// see if we should send out a new batch of telemetry.
|
|
queuedTimersFiredPerWakeup[queuedTimerFiredCount] = timersFiredThisWakeup;
|
|
++queuedTimerFiredCount;
|
|
if (queuedTimerFiredCount == kMaxQueuedTimerFired) {
|
|
glean::timer_thread::timers_fired_per_wakeup.AccumulateSamples(
|
|
queuedTimersFiredPerWakeup);
|
|
queuedTimerFiredCount = 0;
|
|
}
|
|
}
|
|
|
|
#if TIMER_THREAD_STATISTICS
|
|
{
|
|
size_t bucketIndex = 0;
|
|
while (bucketIndex < sTimersFiredPerWakeupBucketCount - 1 &&
|
|
timersFiredThisWakeup >
|
|
sTimersFiredPerWakeupThresholds[bucketIndex]) {
|
|
++bucketIndex;
|
|
}
|
|
MOZ_ASSERT(bucketIndex < sTimersFiredPerWakeupBucketCount);
|
|
++mTimersFiredPerWakeup[bucketIndex];
|
|
|
|
++mTotalWakeupCount;
|
|
if (mNotified) {
|
|
++mTimersFiredPerNotifiedWakeup[bucketIndex];
|
|
++mTotalNotifiedWakeupCount;
|
|
} else {
|
|
++mTimersFiredPerUnnotifiedWakeup[bucketIndex];
|
|
++mTotalUnnotifiedWakeupCount;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
timersFiredThisWakeup = 0;
|
|
|
|
mWaiting = true;
|
|
mNotified = false;
|
|
|
|
{
|
|
AUTO_PROFILER_TRACING_MARKER("TimerThread", "Wait", OTHER);
|
|
mMonitor.Wait(waitFor);
|
|
}
|
|
if (mNotified) {
|
|
forceRunNextTimer = false;
|
|
}
|
|
mWaiting = false;
|
|
}
|
|
|
|
// About to shut down - let's send out the final batch of timers fired counts.
|
|
if (queuedTimerFiredCount != 0) {
|
|
queuedTimersFiredPerWakeup.SetLengthAndRetainStorage(queuedTimerFiredCount);
|
|
glean::timer_thread::timers_fired_per_wakeup.AccumulateSamples(
|
|
queuedTimersFiredPerWakeup);
|
|
}
|
|
|
|
return NS_OK;
|
|
}
|
|
|
|
nsresult TimerThread::AddTimer(nsTimerImpl* aTimer,
|
|
const MutexAutoLock& aProofOfLock) {
|
|
MonitorAutoLock lock(mMonitor);
|
|
AUTO_TIMERS_STATS(TimerThread_AddTimer);
|
|
|
|
if (!aTimer->mEventTarget) {
|
|
return NS_ERROR_NOT_INITIALIZED;
|
|
}
|
|
|
|
nsresult rv = Init();
|
|
if (NS_FAILED(rv)) {
|
|
return rv;
|
|
}
|
|
|
|
// Awaken the timer thread if:
|
|
// - This timer needs to fire *before* the Timer Thread is scheduled to wake
|
|
// up.
|
|
// AND/OR
|
|
// - The delay is 0, which is usually meant to be run as soon as possible.
|
|
// Note: Even if the thread is scheduled to wake up now/soon, on some
|
|
// systems there could be a significant delay compared to notifying, which
|
|
// is almost immediate; and some users of 0-delay depend on it being this
|
|
// fast!
|
|
const TimeDuration minTimerDelay = TimeDuration::FromMilliseconds(
|
|
StaticPrefs::timer_minimum_firing_delay_tolerance_ms());
|
|
const TimeDuration maxTimerDelay = TimeDuration::FromMilliseconds(
|
|
StaticPrefs::timer_maximum_firing_delay_tolerance_ms());
|
|
const TimeDuration firingDelay = ComputeAcceptableFiringDelay(
|
|
aTimer->mDelay, minTimerDelay, maxTimerDelay);
|
|
const bool firingBeforeNextWakeup =
|
|
mIntendedWakeupTime.IsNull() ||
|
|
(aTimer->mTimeout + firingDelay < mIntendedWakeupTime);
|
|
const bool wakeUpTimerThread =
|
|
mWaiting && (firingBeforeNextWakeup || aTimer->mDelay.IsZero());
|
|
|
|
#if TIMER_THREAD_STATISTICS
|
|
if (mTotalTimersAdded == 0) {
|
|
mFirstTimerAdded = TimeStamp::Now();
|
|
}
|
|
++mTotalTimersAdded;
|
|
#endif
|
|
|
|
// Add the timer to our list.
|
|
if (!AddTimerInternal(*aTimer)) {
|
|
return NS_ERROR_OUT_OF_MEMORY;
|
|
}
|
|
|
|
if (wakeUpTimerThread) {
|
|
mNotified = true;
|
|
mMonitor.Notify();
|
|
}
|
|
|
|
if (profiler_thread_is_being_profiled_for_markers(mProfilerThreadId)) {
|
|
nsAutoCString name;
|
|
aTimer->GetName(name, aProofOfLock);
|
|
|
|
nsLiteralCString prefix("Anonymous_");
|
|
profiler_add_marker(
|
|
"AddTimer", geckoprofiler::category::OTHER,
|
|
MarkerOptions(MarkerThreadId(mProfilerThreadId),
|
|
MarkerStack::MaybeCapture(
|
|
name.Equals("nonfunction:JS") ||
|
|
StringHead(name, prefix.Length()) == prefix)),
|
|
AddRemoveTimerMarker{}, name, aTimer->mDelay.ToMilliseconds(),
|
|
MarkerThreadId::CurrentThread());
|
|
}
|
|
|
|
return NS_OK;
|
|
}
|
|
|
|
nsresult TimerThread::RemoveTimer(nsTimerImpl* aTimer,
|
|
const MutexAutoLock& aProofOfLock) {
|
|
MonitorAutoLock lock(mMonitor);
|
|
AUTO_TIMERS_STATS(TimerThread_RemoveTimer);
|
|
|
|
// Remove the timer from our array. Tell callers that aTimer was not found
|
|
// by returning NS_ERROR_NOT_AVAILABLE.
|
|
|
|
if (!RemoveTimerInternal(*aTimer)) {
|
|
return NS_ERROR_NOT_AVAILABLE;
|
|
}
|
|
|
|
#if TIMER_THREAD_STATISTICS
|
|
++mTotalTimersRemoved;
|
|
#endif
|
|
|
|
// Note: The timer thread is *not* awoken.
|
|
// The removed-timer entry is just left null, and will be reused (by a new or
|
|
// re-set timer) or discarded (when the timer thread logic handles non-null
|
|
// timers around it).
|
|
// If this was the front timer, and in the unlikely case that its entry is not
|
|
// soon reused by a re-set timer, the timer thread will wake up at the
|
|
// previously-scheduled time, but will quickly notice that there is no actual
|
|
// pending timer, and will restart its wait until the following real timeout.
|
|
|
|
if (profiler_thread_is_being_profiled_for_markers(mProfilerThreadId)) {
|
|
nsAutoCString name;
|
|
aTimer->GetName(name, aProofOfLock);
|
|
|
|
nsLiteralCString prefix("Anonymous_");
|
|
// This marker is meant to help understand the behavior of the timer thread.
|
|
profiler_add_marker(
|
|
"RemoveTimer", geckoprofiler::category::OTHER,
|
|
MarkerOptions(MarkerThreadId(mProfilerThreadId),
|
|
MarkerStack::MaybeCapture(
|
|
name.Equals("nonfunction:JS") ||
|
|
StringHead(name, prefix.Length()) == prefix)),
|
|
AddRemoveTimerMarker{}, name, aTimer->mDelay.ToMilliseconds(),
|
|
MarkerThreadId::CurrentThread());
|
|
// This adds a marker with the timer name as the marker name, to make it
|
|
// obvious which timers are being used. This marker will be useful to
|
|
// understand which timers might be added and removed excessively often.
|
|
profiler_add_marker(name, geckoprofiler::category::TIMER,
|
|
MarkerOptions(MarkerTiming::IntervalUntilNowFrom(
|
|
aTimer->mTimeout - aTimer->mDelay),
|
|
MarkerThreadId(mProfilerThreadId)),
|
|
TimerMarker{}, aTimer->mDelay.ToMilliseconds(),
|
|
aTimer->mType, MarkerThreadId::CurrentThread(), true);
|
|
}
|
|
|
|
return NS_OK;
|
|
}
|
|
|
|
TimeStamp TimerThread::FindNextFireTimeForCurrentThread(TimeStamp aDefault,
|
|
uint32_t aSearchBound) {
|
|
MonitorAutoLock lock(mMonitor);
|
|
AUTO_TIMERS_STATS(TimerThread_FindNextFireTimeForCurrentThread);
|
|
|
|
for (const Entry& entry : mTimers) {
|
|
const nsTimerImpl* timer = entry.Value();
|
|
if (timer) {
|
|
if (entry.Timeout() > aDefault) {
|
|
return aDefault;
|
|
}
|
|
|
|
// Don't yield to timers created with the *_LOW_PRIORITY type.
|
|
if (!timer->IsLowPriority()) {
|
|
bool isOnCurrentThread = false;
|
|
nsresult rv =
|
|
timer->mEventTarget->IsOnCurrentThread(&isOnCurrentThread);
|
|
if (NS_SUCCEEDED(rv) && isOnCurrentThread) {
|
|
return entry.Timeout();
|
|
}
|
|
}
|
|
|
|
if (aSearchBound == 0) {
|
|
// Return the currently highest timeout when we reach the bound.
|
|
// This won't give accurate information if we stop before finding
|
|
// any timer for the current thread, but at least won't report too
|
|
// long idle period.
|
|
return timer->mTimeout;
|
|
}
|
|
|
|
--aSearchBound;
|
|
}
|
|
}
|
|
|
|
// No timers for this thread, return the default.
|
|
return aDefault;
|
|
}
|
|
|
|
// This function must be called from within a lock
|
|
// Also: we hold the mutex for the nsTimerImpl.
|
|
bool TimerThread::AddTimerInternal(nsTimerImpl& aTimer) {
|
|
mMonitor.AssertCurrentThreadOwns();
|
|
aTimer.mMutex.AssertCurrentThreadOwns();
|
|
AUTO_TIMERS_STATS(TimerThread_AddTimerInternal);
|
|
if (mShutdown) {
|
|
return false;
|
|
}
|
|
|
|
LogTimerEvent::LogDispatch(&aTimer);
|
|
|
|
const TimeStamp& timeout = aTimer.mTimeout;
|
|
const size_t insertionIndex = ComputeTimerInsertionIndex(timeout);
|
|
|
|
if (insertionIndex != 0 && !mTimers[insertionIndex - 1].Value()) {
|
|
// Very common scenario in practice: The timer just before the insertion
|
|
// point is canceled, overwrite it.
|
|
AUTO_TIMERS_STATS(TimerThread_AddTimerInternal_overwrite_before);
|
|
mTimers[insertionIndex - 1] = Entry{aTimer};
|
|
return true;
|
|
}
|
|
|
|
const size_t length = mTimers.Length();
|
|
if (insertionIndex == length) {
|
|
// We're at the end (including it's the very first insertion), add new timer
|
|
// at the end.
|
|
AUTO_TIMERS_STATS(TimerThread_AddTimerInternal_append);
|
|
return mTimers.AppendElement(Entry{aTimer}, mozilla::fallible);
|
|
}
|
|
|
|
if (!mTimers[insertionIndex].Value()) {
|
|
// The timer at the insertion point is canceled, overwrite it.
|
|
AUTO_TIMERS_STATS(TimerThread_AddTimerInternal_overwrite);
|
|
mTimers[insertionIndex] = Entry{aTimer};
|
|
return true;
|
|
}
|
|
|
|
// The new timer has to be inserted.
|
|
AUTO_TIMERS_STATS(TimerThread_AddTimerInternal_insert);
|
|
// The capacity should be checked first, because if it needs to be increased
|
|
// and the memory allocation fails, only the new timer should be lost.
|
|
if (length == mTimers.Capacity() && mTimers[length - 1].Value()) {
|
|
// We have reached capacity, and the last entry is not canceled, so we
|
|
// really want to increase the capacity in case the extra slot is required.
|
|
// To force-expand the array, append a canceled-timer entry with a timestamp
|
|
// far in the future.
|
|
// This empty Entry may be used below to receive the moved-from previous
|
|
// entry. If not, it may be used in a later call if we need to append a new
|
|
// timer at the end.
|
|
AUTO_TIMERS_STATS(TimerThread_AddTimerInternal_insert_expand);
|
|
if (!mTimers.AppendElement(
|
|
Entry{mTimers[length - 1].Timeout() +
|
|
TimeDuration::FromSeconds(365.0 * 24.0 * 60.0 * 60.0)},
|
|
mozilla::fallible)) {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
// Extract the timer at the insertion point, and put the new timer in its
|
|
// place.
|
|
Entry extractedEntry = std::exchange(mTimers[insertionIndex], Entry{aTimer});
|
|
// Following entries can be pushed until we hit a canceled timer or the end.
|
|
for (size_t i = insertionIndex + 1; i < length; ++i) {
|
|
Entry& entryRef = mTimers[i];
|
|
if (!entryRef.Value()) {
|
|
// Canceled entry, overwrite it with the extracted entry from before.
|
|
COUNT_TIMERS_STATS(TimerThread_AddTimerInternal_insert_overwrite);
|
|
entryRef = std::move(extractedEntry);
|
|
return true;
|
|
}
|
|
// Write extracted entry from before, and extract current entry.
|
|
COUNT_TIMERS_STATS(TimerThread_AddTimerInternal_insert_shifts);
|
|
std::swap(entryRef, extractedEntry);
|
|
}
|
|
// We've reached the end of the list, with still one extracted entry to
|
|
// re-insert. We've checked the capacity above, this cannot fail.
|
|
COUNT_TIMERS_STATS(TimerThread_AddTimerInternal_insert_append);
|
|
mTimers.AppendElement(std::move(extractedEntry));
|
|
return true;
|
|
}
|
|
|
|
// This function must be called from within a lock
|
|
// Also: we hold the mutex for the nsTimerImpl.
|
|
bool TimerThread::RemoveTimerInternal(nsTimerImpl& aTimer) {
|
|
mMonitor.AssertCurrentThreadOwns();
|
|
aTimer.mMutex.AssertCurrentThreadOwns();
|
|
AUTO_TIMERS_STATS(TimerThread_RemoveTimerInternal);
|
|
if (!aTimer.IsInTimerThread()) {
|
|
COUNT_TIMERS_STATS(TimerThread_RemoveTimerInternal_not_in_list);
|
|
return false;
|
|
}
|
|
AUTO_TIMERS_STATS(TimerThread_RemoveTimerInternal_in_list);
|
|
for (auto& entry : mTimers) {
|
|
if (entry.Value() == &aTimer) {
|
|
entry.Forget();
|
|
return true;
|
|
}
|
|
}
|
|
MOZ_ASSERT(!aTimer.IsInTimerThread(),
|
|
"Not found in the list but it should be!?");
|
|
return false;
|
|
}
|
|
|
|
void TimerThread::RemoveLeadingCanceledTimersInternal() {
|
|
mMonitor.AssertCurrentThreadOwns();
|
|
AUTO_TIMERS_STATS(TimerThread_RemoveLeadingCanceledTimersInternal);
|
|
|
|
size_t toRemove = 0;
|
|
while (toRemove < mTimers.Length() && !mTimers[toRemove].Value()) {
|
|
++toRemove;
|
|
}
|
|
mTimers.RemoveElementsAt(0, toRemove);
|
|
}
|
|
|
|
void TimerThread::RemoveFirstTimerInternal() {
|
|
mMonitor.AssertCurrentThreadOwns();
|
|
AUTO_TIMERS_STATS(TimerThread_RemoveFirstTimerInternal);
|
|
MOZ_ASSERT(!mTimers.IsEmpty());
|
|
mTimers.RemoveElementAt(0);
|
|
}
|
|
|
|
void TimerThread::PostTimerEvent(already_AddRefed<nsTimerImpl> aTimerRef) {
|
|
mMonitor.AssertCurrentThreadOwns();
|
|
AUTO_TIMERS_STATS(TimerThread_PostTimerEvent);
|
|
|
|
RefPtr<nsTimerImpl> timer(aTimerRef);
|
|
|
|
#if TIMER_THREAD_STATISTICS
|
|
const double actualFiringDelay =
|
|
std::max((TimeStamp::Now() - timer->mTimeout).ToMilliseconds(), 0.0);
|
|
if (mNotified) {
|
|
++mTotalTimersFiredNotified;
|
|
mTotalActualTimerFiringDelayNotified += actualFiringDelay;
|
|
} else {
|
|
++mTotalTimersFiredUnnotified;
|
|
mTotalActualTimerFiringDelayUnnotified += actualFiringDelay;
|
|
}
|
|
#endif
|
|
|
|
if (!timer->mEventTarget) {
|
|
NS_ERROR("Attempt to post timer event to NULL event target");
|
|
return;
|
|
}
|
|
|
|
// XXX we may want to reuse this nsTimerEvent in the case of repeating timers.
|
|
|
|
// Since we already addref'd 'timer', we don't need to addref here.
|
|
// We will release either in ~nsTimerEvent(), or pass the reference back to
|
|
// the caller. We need to copy the generation number from this timer into the
|
|
// event, so we can avoid firing a timer that was re-initialized after being
|
|
// canceled.
|
|
|
|
nsCOMPtr<nsIEventTarget> target = timer->mEventTarget;
|
|
|
|
void* p = nsTimerEvent::operator new(sizeof(nsTimerEvent));
|
|
if (!p) {
|
|
return;
|
|
}
|
|
RefPtr<nsTimerEvent> event =
|
|
::new (KnownNotNull, p) nsTimerEvent(timer.forget(), mProfilerThreadId);
|
|
|
|
nsresult rv;
|
|
{
|
|
// We release mMonitor around the Dispatch because if the Dispatch interacts
|
|
// with the timer API we'll deadlock.
|
|
MonitorAutoUnlock unlock(mMonitor);
|
|
rv = target->Dispatch(event, NS_DISPATCH_NORMAL);
|
|
if (NS_FAILED(rv)) {
|
|
timer = event->ForgetTimer();
|
|
// We do this to avoid possible deadlock by taking the two locks in a
|
|
// different order than is used in RemoveTimer(). RemoveTimer() has
|
|
// aTimer->mMutex first. We use timer.get() to keep static analysis
|
|
// happy
|
|
// NOTE: I'm not sure that any of the below is actually necessary. It
|
|
// seems to me that the timer that we're trying to fire will have already
|
|
// been removed prior to this.
|
|
MutexAutoLock lock1(timer.get()->mMutex);
|
|
MonitorAutoLock lock2(mMonitor);
|
|
RemoveTimerInternal(*timer);
|
|
}
|
|
}
|
|
}
|
|
|
|
void TimerThread::DoBeforeSleep() {
|
|
// Mainthread
|
|
MonitorAutoLock lock(mMonitor);
|
|
mSleeping = true;
|
|
}
|
|
|
|
// Note: wake may be notified without preceding sleep notification
|
|
void TimerThread::DoAfterSleep() {
|
|
// Mainthread
|
|
MonitorAutoLock lock(mMonitor);
|
|
mSleeping = false;
|
|
|
|
// Wake up the timer thread to re-process the array to ensure the sleep delay
|
|
// is correct, and fire any expired timers (perhaps quite a few)
|
|
mNotified = true;
|
|
PROFILER_MARKER_UNTYPED("AfterSleep", OTHER,
|
|
MarkerThreadId(mProfilerThreadId));
|
|
mMonitor.Notify();
|
|
}
|
|
|
|
NS_IMETHODIMP
|
|
TimerThread::Observe(nsISupports* /* aSubject */, const char* aTopic,
|
|
const char16_t* /* aData */) {
|
|
if (StaticPrefs::timer_ignore_sleep_wake_notifications()) {
|
|
return NS_OK;
|
|
}
|
|
|
|
if (strcmp(aTopic, "sleep_notification") == 0 ||
|
|
strcmp(aTopic, "suspend_process_notification") == 0) {
|
|
DoBeforeSleep();
|
|
} else if (strcmp(aTopic, "wake_notification") == 0 ||
|
|
strcmp(aTopic, "resume_process_notification") == 0) {
|
|
DoAfterSleep();
|
|
}
|
|
|
|
return NS_OK;
|
|
}
|
|
|
|
uint32_t TimerThread::AllowedEarlyFiringMicroseconds() {
|
|
MonitorAutoLock lock(mMonitor);
|
|
return mAllowedEarlyFiringMicroseconds;
|
|
}
|
|
|
|
#if TIMER_THREAD_STATISTICS
|
|
void TimerThread::PrintStatistics() const {
|
|
mMonitor.AssertCurrentThreadOwns();
|
|
|
|
const TimeStamp freshNow = TimeStamp::Now();
|
|
const double timeElapsed = mFirstTimerAdded.IsNull()
|
|
? 0.0
|
|
: (freshNow - mFirstTimerAdded).ToSeconds();
|
|
printf_stderr("TimerThread Stats (Total time %8.2fs)\n", timeElapsed);
|
|
|
|
printf_stderr("Added: %6llu Removed: %6llu Fired: %6llu\n", mTotalTimersAdded,
|
|
mTotalTimersRemoved,
|
|
mTotalTimersFiredNotified + mTotalTimersFiredUnnotified);
|
|
|
|
auto PrintTimersFiredBucket =
|
|
[](const AutoTArray<size_t, sTimersFiredPerWakeupBucketCount>& buckets,
|
|
const size_t wakeupCount, const size_t timersFiredCount,
|
|
const double totalTimerDelay, const char* label) {
|
|
printf_stderr("%s : [", label);
|
|
for (size_t bucketVal : buckets) {
|
|
printf_stderr(" %5llu", bucketVal);
|
|
}
|
|
printf_stderr(
|
|
" ] Wake-ups/timer %6llu / %6llu (%7.4f) Avg Timer Delay %7.4f\n",
|
|
wakeupCount, timersFiredCount,
|
|
static_cast<double>(wakeupCount) / timersFiredCount,
|
|
totalTimerDelay / timersFiredCount);
|
|
};
|
|
|
|
printf_stderr("Wake-ups:\n");
|
|
PrintTimersFiredBucket(
|
|
mTimersFiredPerWakeup, mTotalWakeupCount,
|
|
mTotalTimersFiredNotified + mTotalTimersFiredUnnotified,
|
|
mTotalActualTimerFiringDelayNotified +
|
|
mTotalActualTimerFiringDelayUnnotified,
|
|
"Total ");
|
|
PrintTimersFiredBucket(mTimersFiredPerNotifiedWakeup,
|
|
mTotalNotifiedWakeupCount, mTotalTimersFiredNotified,
|
|
mTotalActualTimerFiringDelayNotified, "Notified ");
|
|
PrintTimersFiredBucket(mTimersFiredPerUnnotifiedWakeup,
|
|
mTotalUnnotifiedWakeupCount,
|
|
mTotalTimersFiredUnnotified,
|
|
mTotalActualTimerFiringDelayUnnotified, "Unnotified ");
|
|
|
|
printf_stderr("Early Wake-ups: %6llu Avg: %7.4fms\n", mEarlyWakeups,
|
|
mTotalEarlyWakeupTime / mEarlyWakeups);
|
|
}
|
|
#endif
|
|
|
|
/* This nsReadOnlyTimer class is used for the values returned by the
|
|
* TimerThread::GetTimers method.
|
|
* It is not possible to return a strong reference to the nsTimerImpl
|
|
* instance (that could extend the lifetime of the timer and cause it to fire
|
|
* a callback pointing to already freed memory) or a weak reference
|
|
* (nsSupportsWeakReference doesn't support freeing the referee on a thread
|
|
* that isn't the thread that owns the weak reference), so instead the timer
|
|
* name, delay and type are copied to a new object. */
|
|
class nsReadOnlyTimer final : public nsITimer {
|
|
public:
|
|
explicit nsReadOnlyTimer(const nsACString& aName, uint32_t aDelay,
|
|
uint32_t aType)
|
|
: mName(aName), mDelay(aDelay), mType(aType) {}
|
|
NS_DECL_ISUPPORTS
|
|
|
|
NS_IMETHOD Init(nsIObserver* aObserver, uint32_t aDelayInMs,
|
|
uint32_t aType) override {
|
|
return NS_ERROR_NOT_IMPLEMENTED;
|
|
}
|
|
NS_IMETHOD InitWithCallback(nsITimerCallback* aCallback, uint32_t aDelayInMs,
|
|
uint32_t aType) override {
|
|
return NS_ERROR_NOT_IMPLEMENTED;
|
|
}
|
|
NS_IMETHOD InitHighResolutionWithCallback(nsITimerCallback* aCallback,
|
|
const mozilla::TimeDuration& aDelay,
|
|
uint32_t aType) override {
|
|
return NS_ERROR_NOT_IMPLEMENTED;
|
|
}
|
|
NS_IMETHOD Cancel(void) override { return NS_ERROR_NOT_IMPLEMENTED; }
|
|
NS_IMETHOD InitWithNamedFuncCallback(nsTimerCallbackFunc aCallback,
|
|
void* aClosure, uint32_t aDelay,
|
|
uint32_t aType,
|
|
const char* aName) override {
|
|
return NS_ERROR_NOT_IMPLEMENTED;
|
|
}
|
|
NS_IMETHOD InitHighResolutionWithNamedFuncCallback(
|
|
nsTimerCallbackFunc aCallback, void* aClosure,
|
|
const mozilla::TimeDuration& aDelay, uint32_t aType,
|
|
const char* aName) override {
|
|
return NS_ERROR_NOT_IMPLEMENTED;
|
|
}
|
|
|
|
NS_IMETHOD GetName(nsACString& aName) override {
|
|
aName = mName;
|
|
return NS_OK;
|
|
}
|
|
NS_IMETHOD GetDelay(uint32_t* aDelay) override {
|
|
*aDelay = mDelay;
|
|
return NS_OK;
|
|
}
|
|
NS_IMETHOD SetDelay(uint32_t aDelay) override {
|
|
return NS_ERROR_NOT_IMPLEMENTED;
|
|
}
|
|
NS_IMETHOD GetType(uint32_t* aType) override {
|
|
*aType = mType;
|
|
return NS_OK;
|
|
}
|
|
NS_IMETHOD SetType(uint32_t aType) override {
|
|
return NS_ERROR_NOT_IMPLEMENTED;
|
|
}
|
|
NS_IMETHOD GetClosure(void** aClosure) override {
|
|
return NS_ERROR_NOT_IMPLEMENTED;
|
|
}
|
|
NS_IMETHOD GetCallback(nsITimerCallback** aCallback) override {
|
|
return NS_ERROR_NOT_IMPLEMENTED;
|
|
}
|
|
NS_IMETHOD GetTarget(nsIEventTarget** aTarget) override {
|
|
return NS_ERROR_NOT_IMPLEMENTED;
|
|
}
|
|
NS_IMETHOD SetTarget(nsIEventTarget* aTarget) override {
|
|
return NS_ERROR_NOT_IMPLEMENTED;
|
|
}
|
|
NS_IMETHOD GetAllowedEarlyFiringMicroseconds(
|
|
uint32_t* aAllowedEarlyFiringMicroseconds) override {
|
|
return NS_ERROR_NOT_IMPLEMENTED;
|
|
}
|
|
size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) override {
|
|
return sizeof(*this);
|
|
}
|
|
|
|
private:
|
|
nsCString mName;
|
|
uint32_t mDelay;
|
|
uint32_t mType;
|
|
~nsReadOnlyTimer() = default;
|
|
};
|
|
|
|
NS_IMPL_ISUPPORTS(nsReadOnlyTimer, nsITimer)
|
|
|
|
nsresult TimerThread::GetTimers(nsTArray<RefPtr<nsITimer>>& aRetVal) {
|
|
nsTArray<RefPtr<nsTimerImpl>> timers;
|
|
{
|
|
MonitorAutoLock lock(mMonitor);
|
|
for (const auto& entry : mTimers) {
|
|
nsTimerImpl* timer = entry.Value();
|
|
if (!timer) {
|
|
continue;
|
|
}
|
|
timers.AppendElement(timer);
|
|
}
|
|
}
|
|
|
|
for (nsTimerImpl* timer : timers) {
|
|
nsAutoCString name;
|
|
timer->GetName(name);
|
|
|
|
uint32_t delay;
|
|
timer->GetDelay(&delay);
|
|
|
|
uint32_t type;
|
|
timer->GetType(&type);
|
|
|
|
aRetVal.AppendElement(new nsReadOnlyTimer(name, delay, type));
|
|
}
|
|
|
|
return NS_OK;
|
|
}
|