[Qt-interest] QTimer glitching/pausing on Windows 4.6.2 -- anyone else seen this?

[Ross Bencina]

My app has developed a problem which it never used to have (with 4.4.3). I'm 
trying to track down the cause and just wondering if anyone else has seen 
the same issue in 4.6.2 -- I couldn't find it in the bug tracker. I'm seeing 
this on Windows.

I have a number of UI panes which each run their own 50ms animation timer 
(QTimer) which causes the UI to get redrawn (animates status information 
etc. file playback positions etc). My app can potentially run a lot of these 
timers, although I'm seeing the problem with less than 10 of them at the 
moment.

Since I switched to 4.6.2 I have noticed that the animations sometimes pause 
(for about a second) at random points (about every 3-4 seconds). This 
problem goes away if I continuously move the mouse (but comes back if I stop 
moving the mouse). It isn't a CPU load issue. This happens even when the 
system has <20% load. So it seems like the timer signals or events are 
intermittently stopping being sent for some reason.

I seem to be able to make this start happening if I temporarily overload the 
CPU.

Has anyone else encountered anything like this?

Has the implementation of QTimer significantly changed?

Thanks

Ross.