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QEventDispatcherWin32: use SetCoalescableTimer for (Very)Coarse timers

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The tolerance can be set per timer, unlike on Linux.

Fixes: QTBUG-98316
Change-Id: I5e52dc5b093c43a3b678fffd16b788a30bcb9574
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
This commit is contained in:
Thiago Macieira 2021-11-14 14:00:23 -08:00
parent be0dc7fbb8
commit 5e2ce03510
1 changed files with 41 additions and 7 deletions
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48
src/corelib/kernel/qeventdispatcher_win.cpp
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@ -336,15 +336,47 @@ static HWND qt_create_internal_window(const QEventDispatcherWin32 *eventDispatch
return wnd;
}
static void calculateNextTimeout(WinTimerInfo *t, quint64 currentTime)
static ULONG calculateNextTimeout(WinTimerInfo *t, quint64 currentTime)
{
uint interval = t->interval;
if ((interval >= 20000u && t->timerType != Qt::PreciseTimer) || t->timerType == Qt::VeryCoarseTimer) {
// round the interval, VeryCoarseTimers only have full second accuracy
interval = ((interval + 500)) / 1000 * 1000;
ULONG tolerance = TIMERV_DEFAULT_COALESCING;
switch (t->timerType) {
case Qt::PreciseTimer:
// high precision timer is based on millisecond precision
// so no adjustment is necessary
break;
case Qt::CoarseTimer:
// this timer has up to 5% coarseness
// so our boundaries are 20 ms and 20 s
// below 20 ms, 5% inaccuracy is below 1 ms, so we convert to high precision
// above 20 s, 5% inaccuracy is above 1 s, so we convert to VeryCoarseTimer
if (interval >= 20000) {
t->timerType = Qt::VeryCoarseTimer;
} else if (interval <= 20) {
// no adjustment necessary
t->timerType = Qt::PreciseTimer;
break;
} else {
tolerance = interval / 20;
break;
}
Q_FALLTHROUGH();
case Qt::VeryCoarseTimer:
// the very coarse timer is based on full second precision,
// so we round to closest second (but never to zero)
tolerance = 1000;
if (interval < 1000)
interval = 1000;
else
interval = (interval + 500) / 1000 * 1000;
currentTime = currentTime / 1000 * 1000;
break;
}
t->interval = interval;
t->timeout = currentTime + interval;
return tolerance;
}
void QEventDispatcherWin32Private::registerTimer(WinTimerInfo *t)
@ -354,13 +386,13 @@ void QEventDispatcherWin32Private::registerTimer(WinTimerInfo *t)
Q_Q(QEventDispatcherWin32);
bool ok = false;
calculateNextTimeout(t, qt_msectime());
ULONG tolerance = calculateNextTimeout(t, qt_msectime());
uint interval = t->interval;
if (interval == 0u) {
// optimization for single-shot-zero-timer
QCoreApplication::postEvent(q, new QZeroTimerEvent(t->timerId));
ok = true;
} else if (interval < 20u || t->timerType == Qt::PreciseTimer) {
} else if (tolerance == TIMERV_DEFAULT_COALESCING) {
// 3/2016: Although MSDN states timeSetEvent() is deprecated, the function
// is still deemed to be the most reliable precision timer.
t->fastTimerId = timeSetEvent(interval, 1, qt_fast_timer_proc, DWORD_PTR(t),
@ -370,8 +402,10 @@ void QEventDispatcherWin32Private::registerTimer(WinTimerInfo *t)
if (!ok) {
// user normal timers for (Very)CoarseTimers, or if no more multimedia timers available
ok = SetTimer(internalHwnd, t->timerId, interval, 0);
ok = SetCoalescableTimer(internalHwnd, t->timerId, interval, nullptr, tolerance);
}
if (!ok)
ok = SetTimer(internalHwnd, t->timerId, interval, nullptr);
if (!ok)
qErrnoWarning("QEventDispatcherWin32::registerTimer: Failed to create a timer");