Re: ext4 performance regression 2.6.27-stable versus 2.6.32 andlater

From: Ted Ts'o
Date: Thu Jul 29 2010 - 22:21:06 EST


On Wed, Jul 28, 2010 at 09:51:48PM +0200, Kay Diederichs wrote:
>
> When looking at the I/O statistics while the benchmark is running, we
> see very choppy patterns for 2.6.32, but quite smooth stats for
> 2.6.27-stable.

Could you try to do two things for me? Using (preferably from a
recent e2fsprogs, such as 1.41.11 or 12) run filefrag -v on the files
created from your 2.6.27 run and your 2.6.32 run?

Secondly can capture blktrace results from 2.6.27 and 2.6.32? That
would be very helpful to understand what might be going on.

Either would be helpful; both would be greatly appreciated.

Thanks,

- Ted
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