Re: Slow seek in kernels >= 2.6.18

["Bhagi rathi" <jahnu77@xxxxxxxxx>]

Is it the same on ext file-systems?

Can you run the same tests on disk devices directly to rule out scheduling
issues of  i/o requests
by device drivers?  One way I was thinking that we got a kind of cache
pollution or invalidation
thus exposing to do more seeks.  Can you tell the equivalent file-system
operations that your
application in general do? This will give a lot of insight on what could be
happening.

-Bhagi.

On 10/18/07, Anton A Vorobev <anton.vorobev@xxxxxxxxxxxxxxx> wrote:
>
> Hi!
>
> A question. We've got an application that runs about 30-40 minutes.
> After kernel upgrade from 2.6.17 branch, it runs about 3 hours.
> I've made tests with the help of bonnie++, it shows that random seek
> operations are about 3 times slower in kernels newer than 2.6.18 in
> comparison with 2.6.17. This difference may be seen only during high
> load of a server. When it is in normal state, parameters are rather the
> same.
>
> We use XFS filesystem. Does any one know may it be because of upgrade of
> XFS driver in kernel? Any ideas?
>
> Thanks a lot.
>
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