[Fwd: Re: [ck] Re: Threading issues? [ck-request@vds.kolivas.org: ck Digest, Vol 3, Issue 16]]

[Mike Hearn]

-------- Forwarded Message --------
From: Con Kolivas <kernel at kolivas.org>
To: Mike Hearn <mike at navi.cx>
Cc: ck at vds.kolivas.org
Subject: Re: [ck] Re: Threading issues? [ck-request at vds.kolivas.org: ck
Digest, Vol 3, Issue 16]
Date: Sat, 21 Aug 2004 10:39:21 +1000
Mailer: Mozilla Thunderbird 0.7.1 (X11/20040626)
Mike Hearn wrote:
> On Tue, 17 Aug 2004 10:06:46 +0200, Andreas Mohr wrote:
> 
>>Are we doing some big no-nos in the threading area here?
>>(or maybe it's just done the way it is because we cannot do it a
>>different, better way?)
>>
>>For the whole discussion, please see
>>http://bhhdoa.org.au/pipermail/ck/2004-August/000428.html
> 
> 
> Well, apparently we don't use sched_yield, so the problem must
> lie somewhere else. Maybe Con can help us out here? Alexandre says he
> doesn't know what the issue is either and somebody needs to investigate. I
> guess we do need to concern ourselves over the details :)

Interesting. Probably the most valuable information is that it seems to 
work fine if we artificially limit the threads to exactly the same 
timeslice _or_ we put them at such a low priority that they are forced 
to be guaranteed to round robin one task at a time. This is the way 2.4 
used to work which is why with the new 2.6 schedulers which do far more 
out-of-order rescheduling some applications have a problem; particularly 
under load. I suspect it's actually the latter issue. Locking between 
threads should prevent that being a problem, though. You already 
mentioned that you dont use sched_yield() and I couldn't even begin to 
look at the wine code myself so perhaps you know something more.

The other (useful?) bit of information is that one person solved his 
issue with this:

 >I had a similar problem with Cedega. I fixed it by editing the
 >Cedega/WineX config file and specifying that I wanted to use ALSA
 >instead of WineOSS, then disable mmap for ALSA.

I'm not sure if that fixes all the problems but perhaps that helps.

I'm interested in getting this resolved so please keep me informed.

Cheers,
Con

P.S. Sorry I had trouble posting to your newsgroup.