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Re: Slow seek in kernels >= 2.6.18

To: Anton A Vorobev <anton.vorobev@xxxxxxxxxxxxxxx>
Subject: Re: Slow seek in kernels >= 2.6.18
From: Josef Sipek <jsipek@xxxxxxxxxxxxxxxxx>
Date: Tue, 23 Oct 2007 20:37:06 -0400
Cc: xfs@xxxxxxxxxxx
In-reply-to: <4717156C.3030308@firma.seznam.cz>
References: <4717156C.3030308@firma.seznam.cz>
Sender: xfs-bounce@xxxxxxxxxxx
User-agent: Mutt/1.5.16 (2007-07-16)
On Thu, Oct 18, 2007 at 10:12:28AM +0200, Anton A Vorobev 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.

I think that's about when the defaults for few /proc/sys/vm/ vars changed.
One from 10 to 5, and another from 40 to 10. I forget the exact filenames.

Josef 'Jeff' Sipek.

-- 
Once you have their hardware. Never give it back.
(The First Rule of Hardware Acquisition)


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