J. Leclanche

On Tue, Mar 6, 2012 at 4:37 PM, Maarten Lankhorst <m.b.lankhorst@gmail.com> wrote:

Hey Joerg,

Op 06-03-12 11:21, Joerg-Cyril.Hoehle@t-systems.com schreef:

> Hi,
>
> If you can run MS-Windows without virtual machine, please visit testbot
> https://testbot.winehq.org/JobDetails.pl?Key=17175
> download the 32 or 64bit executable and execute it.
>
> I can't really trust vm machines for timing, but so far it appears that:
>
> - Vista/w2k8SE/w7 perform rate correction so as to maintain an average number of callbacks
> sync.c:583: TimerQueue period 10ms with 0 stress, flags 0
> sync.c:558: thread 1340 hpctime 30 delta 15
> sync.c:558: thread 1340 hpctime 46 delta 16
> sync.c:558: thread 1340 hpctime 46 delta 0
> sync.c:601: 80 callbacks within 796/800ms, avg 9.950/10
>
> They'll refire with up to 0 wait upon noticing that it's very late!
>
> sync.c:583: TimerQueue period 10ms with 7 stress, flags 10
> sync.c:558: thread 1340 hpctime 46 delta 15
> sync.c:570: thread 1340 busy 7ms
> sync.c:558: thread 1340 hpctime 53 delta 7
> sync.c:570: thread 1340 busy 7ms
> sync.c:558: thread 1340 hpctime 62 delta 9
> sync.c:570: thread 1340 busy 7ms
> sync.c:558: thread 1340 hpctime 77 delta 15
> sync.c:570: thread 1340 busy 7ms
> sync.c:558: thread 1340 hpctime 84 delta 7
> sync.c:570: thread 1340 busy 7ms
> sync.c:601: 59 callbacks within 607/600ms, avg 10.288/10
>
> It maintains its average even the callback is busy for 7ms within each 10ms interval.
>
> sync.c:583: TimerQueue period 10ms with 12 stress, flags 20
> sync.c:558: thread 828 hpctime 31 delta 12
> sync.c:570: thread 828 busy 12ms
> sync.c:558: thread 828 hpctime 43 delta 12
> sync.c:570: thread 828 busy 12ms
> sync.c:601: 42 callbacks within 507/400ms, avg 12.071/10
>
> This one surprises me. No multiple threads are used. Wine uses several
> threads here. When every callback is busy for 12ms, MS does not reach
> an average 10ms per invocation, whereas Wine does, thanks to several
> threads that execute the callbacks concurrently.
>
> I want to figure out why several threads were not used.
>
> sync.c:601: 40 callbacks within 4624/4680ms, avg 115.600/117
> Ok. Note that the average is usually slightly lower than expected, simply
> because the first callback is asked to fire at time period/2.
>
> - w2k/xp do not maintain an average (at least on testbot)
> sync.c:583: TimerQueue period 10ms with 0 stress, flags 0
> sync.c:558: thread 836 hpctime 30 delta 15
> sync.c:558: thread 836 hpctime 46 delta 16
> sync.c:601: 51 callbacks within 796/800ms, avg 15.608/10
>
> So at least in testbot, the minimum rate is the well-known 15.625ms interval.
> Note that the 15.625ms is visible in the w7 testbot results too.
>
> sync.c:583: TimerQueue period 117ms with 0 stress, flags 20
> sync.c:558: thread 840 hpctime 311 delta 125
> sync.c:558: thread 840 hpctime 436 delta 125
> sync.c:601: 37 callbacks within 4561/4680ms, avg 123.270/117
>
> Unlike w7, it never corrects to a smaller interval like 109ms to reach
> the requested average of 117ms.
>
> This is good news for audio in Wine, because we can make
> CreateTimerQueue mimic Vista/w2k8/w7 behaviour to give us a stable rate (on average).
>
> The logs are quite long, you can send me them per e-mail.
>
> Thank you,
> Jörg Höhle
>

Have you tried changing the resolution with timeBeginPeriod? Supposedly affects those too..

~Maarten