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

[Con Kolivas]

Mike Hearn wrote:
>>> 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.
> 
> 
> Hi Con,
> 
> One thought that occurred to me, and this is just a random theory, is 
> that maybe the issue is not with the Wine code but the Win32 code run on 
> top of it. Do you know how 2.6 scheduling compares with 2.4 and Windows 
> (NT) scheduling? Could it be that some apps are written to expect 
> Windows-style scheduling and fail to work if they don't get it?

I argued with myself about the logic in this for ages. The best I could 
come up with is - I don't know :| I'd need to know about windows 
scheduling (which I don't) and how wine treats that scheduling (which I 
also don't).

Cheers,
Con
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