Re: 2.6.12-rc2-mm3

[Steven Pratt]

Andrew Morton wrote:

> Nick Piggin <nickpiggin@xxxxxxxxxxxx> wrote:
>  
>
> > > - The effects of tcq on AS are much less disastrous than I thought they
> > >      
> > >  were.  Do I have the wrong workload?  Memory fails me.  Or did we fix the
> > >  anticipatory scheduler?
> > >
> > >
> >
> > Yes, we did fix it ;)
> > Quite a long time ago, so maybe you are thinking of something else
> > (I haven't been able to work it out).
> >    
>
> Steve Pratt's ols2004 presentation made AS look pretty bad.  However the
> numbers in the proceedings
> (http://www.finux.org/proceedings/LinuxSymposium2004_V2.pdf) are much less
> stark.
>
> Steve, what's up with that?  The slides which you talked to had some awful
> numbers.  Was it the same set of tests?
>  
I highlighted a few cases where AS went really wrong during the 
presentation, like on really large RAID 0 arrays, but in general 
(referring back to slides) AS trailed other schedulers by 5-10% on ext3, 
but had real trouble with XFS, losing by as much as %145 on 5disk raid5 
system for a mix of workloads.  Perhaps this is the piece you remember.


Steve
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