Message-ID: <425BFEE5.8080702@austin.ibm.com>
Date: Tue, 12 Apr 2005 12:01:25 -0500
From: Steven Pratt <slpratt@austin.ibm.com>
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To: Andrew Morton <akpm@osdl.org>
CC: Nick Piggin <nickpiggin@yahoo.com.au>, linux-kernel@vger.kernel.org,
       axboe@suse.de
Subject: Re: 2.6.12-rc2-mm3
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Andrew Morton wrote:

>Nick Piggin <nickpiggin@yahoo.com.au> 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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