Re: Serious performance regression in Wine applications and Linux 2.6.24.*

[Ray Lee]

On Tue, Mar 25, 2008 at 5:12 AM, Kai <epimetreus@xxxxxxxxxxx> wrote:
>
>  On Sat, 22 Mar 2008 21:47:52 -0700, "Ray Lee" <ray-lk@xxxxxxxxxxxxx>
>  said:
>
>
> > On Sat, Mar 22, 2008 at 7:49 PM, Kai <epimetreus@xxxxxxxxxxx> wrote:
>  > > Performance degrades by about 60% when I run Wine under any of the
>  > >  2.6.24.* kernels. Attached are the output of lspci -vv and the two
>  > >  config files of each kernel.
>  > >
>  > >  I upgraded to 2.6.24, back to 2.6.23.(not sure), then tried 2.6.24.1 and
>  > >  2.6.24.3 and the issue is present in both; it's severe enough that Wine
>  > >  apps are virtually unusable for me with this version of the kernel; I'm
>  > >  having to use 2.6.23 until this somehow is resolved.
>  > >
>  > >  I'd like some help figuring out why this performance regression exists,
>  > >  and what can be done to mitigate it.
>  >
>  > As wine has a 'wineserver' running in a separate process, it may be
>  > related to scheduler changes.
>  >
>  > Regardless, if you have the time, please retest using he latest git
>  > head (or nightly snapshot), and see if the performance regression is
>  > still there, and report back. (There have been a lot of changes
>  > between 2.6.24 and current git head that impact the scheduler.)
>  >
>  > Please ensure that the fair group scheduler is disabled in your tests
>  > (just as you have in your 2.6.24 config you attached).
>
>  As mentioned in another response, it was happening as recently as
>  2.6.25-rc6-git7; I'm currently performing a git bisect between 2.6.23
>  and 2.6.24, unless someone has a better idea; it seems my best option,
>  as I'm not really very experienced with kernel hacking or debugging.
>

Andi's idea of looking for excessive context switches is good -- I
didn't see a response to that one. Other than that, if you're only
noticing the issue in 3d games, then it could be several things (not
just the scheduler). Even just a few bisects (or testings of nightly
snapshots) would help narrow it down.

Ray
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