Details
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Bug
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Resolution: Fixed
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P2: Important
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6.7.1, 6.8.0 Beta1
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None
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Windows 11 Pro
MSVC 2019
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Windows
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b039d2251 (dev), eb208a6bb (6.8), 19afb7722 (6.7)
Description
The performance of `timerEvent` has noticeably degraded in Qt versions 6.7.1 and 6.8.0-beta1 compared to Qt 6.6.1.
This issue becomes evident when building and running the attached timertest.zip
.
The difference in behavior appears to be introduced by the following commit:
https://codereview.qt-project.org/c/qt/qtbase/+/367377
Steps to reproduce:
- Build and execute timertest.zip using Qt 6.6.1.
- Build and execute timertest.zip using Qt 6.7.1 or Qt 6.8.0-beta1.
- Observe the responsiveness degradation in the latter versions.
The patch 0002_qtbase_add_log.patchhighlights the accumulation of Timer events in the event queue.
e.g.
18:59:21.014 I (25736)[14936] (unknown:0) : QMap((QEvent::Timer, 17)(QEvent::MetaCall, 1)(QEvent::DeferredDelete, 1)(QEvent::LayoutRequest, 2)(QEvent::UpdateRequest, 1)) 22 18:59:22.724 I (25736)[14936] (unknown:0) : QMap((QEvent::Timer, 18)(QEvent::MetaCall, 1)(QEvent::DeferredDelete, 1)(QEvent::LayoutRequest, 2)) 22 18:59:24.536 I (25736)[14936] (unknown:0) : QMap((QEvent::Timer, 19)(QEvent::MetaCall, 1)(QEvent::DeferredDelete, 1)(QEvent::LayoutRequest, 2)(QEvent::UpdateRequest, 1)) 24 18:59:26.455 I (25736)[14936] (unknown:0) : QMap((QEvent::Timer, 20)(QEvent::MetaCall, 1)(QEvent::DeferredDelete, 1)(QEvent::LayoutRequest, 2)) 24 18:59:28.467 I (25736)[14936] (unknown:0) : QMap((QEvent::Timer, 21)(QEvent::MetaCall, 1)(QEvent::DeferredDelete, 1)(QEvent::LayoutRequest, 2)(QEvent::UpdateRequest, 1)) 26 18:59:30.588 I (25736)[14936] (unknown:0) : QMap((QEvent::Timer, 22)(QEvent::MetaCall, 1)(QEvent::DeferredDelete, 1)(QEvent::LayoutRequest, 2)) 26 18:59:32.801 I (25736)[14936] (unknown:0) : QMap((QEvent::Timer, 23)(QEvent::MetaCall, 1)(QEvent::DeferredDelete, 1)(QEvent::LayoutRequest, 2)(QEvent::UpdateRequest, 1)) 28 18:59:35.119 I (25736)[14936] (unknown:0) : QMap((QEvent::Timer, 24)(QEvent::MetaCall, 1)(QEvent::DeferredDelete, 1)(QEvent::LayoutRequest, 2)) 28 18:59:37.538 I (25736)[14936] (unknown:0) : QMap((QEvent::Timer, 25)(QEvent::MetaCall, 1)(QEvent::DeferredDelete, 1)(QEvent::LayoutRequest, 2)(QEvent::UpdateRequest, 1)) 30 18:59:40.053 I (25736)[14936] (unknown:0) : QMap((QEvent::Timer, 26)(QEvent::MetaCall, 1)(QEvent::DeferredDelete, 1)(QEvent::LayoutRequest, 2)) 30 18:59:42.672 I (25736)[14936] (unknown:0) : QMap((QEvent::Timer, 27)(QEvent::MetaCall, 1)(QEvent::DeferredDelete, 1)(QEvent::LayoutRequest, 2)(QEvent::UpdateRequest, 1)) 32 18:59:45.391 I (25736)[14936] (unknown:0) : QMap((QEvent::Timer, 28)(QEvent::MetaCall, 1)(QEvent::DeferredDelete, 1)(QEvent::LayoutRequest, 2)) 32 18:59:48.209 I (25736)[14936] (unknown:0) : QMap((QEvent::Timer, 29)(QEvent::MetaCall, 1)(QEvent::DeferredDelete, 1)(QEvent::LayoutRequest, 2)(QEvent::UpdateRequest, 1)) 34 18:59:51.128 I (25736)[14936] (unknown:0) : QMap((QEvent::Timer, 30)(QEvent::MetaCall, 1)(QEvent::DeferredDelete, 1)(QEvent::LayoutRequest, 2)) 34 18:59:54.151 I (25736)[14936] (unknown:0) : QMap((QEvent::Timer, 31)(QEvent::MetaCall, 1)(QEvent::DeferredDelete, 1)(QEvent::LayoutRequest, 2)(QEvent::UpdateRequest, 1)) 36 ...