wine CPU usage and CreateWaitableTimer

[andrea]

On 01/06/15 20:43, andrea wrote:
> Hi,
>
> I'm trying to understand why AppleWin uses 100% CPU when running in wine vs ~1% in Windows.
>
> my case is wine 1.7.43 vs Windows 7
>
> https://appdb.winehq.org/objectManager.php?sClass=version&iId=29403
> https://bugs.winehq.org/show_bug.cgi?id=34945
>
> basically 97% time is spent in a WaitForSingleObject on a semaphore signalled by a DirectSound
> IReferenceClock via AdvisePeriodic.
> The timer period is set to 1 millisecond.
>
> I have tried an other Windows call to create the timer: CreateWaitableTimer
> The latter uses about 50% CPU, so it is much better, but still not very good.
>
> This is true even on a simple app that does nothing other than waiting for this timer all the time.
>
> Does anybody know
>
> 1) is this normal? should these waits be almost free like they are in Windows?
> 2) what is the best implemented timer in wine that can be used for a periodic event (~1ms)?
>
> Thanks
>
>
>
>

I've tried 4 different function to create a period timer

http://pastebin.com/wt4iTL78

you can compiler it as

// winegcc -g timers.cpp -lwinmm -lole32 -lstrmiids

and then run it as

./a.out X Y

where X is the period of wait in ms, and Y the method
it will wait till 10 seconds and print some statistics
(you can use "time" to time it)

1 - CreateWaitableTimer
2 - IReferenceClock->AdvisePeriodic
3 - CreateTimerQueueTimer
4 - timeSetEvent

if the wait is 1 ms each time I get the following system times (out of ~10 sec of execution, compute 
with "time")

1 - 0.33s
2 - 4.05s
3 - 0.57s
4 - 0.54s

if I wait every 5 ms I get

1 - 0.15s
2 - 3.95s
3 - 0.28s
4 - 0.20s

It feels like option 2 (IReferenceClock) is implemented as a sort of spin lock, its system time does 
not decrease with longer waits.

What do you think?

Andrea