Re: 2.6.12-rc2-mm3

Steven Pratt
2005-04-12T16:59:14Z

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