From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeff Moyer <jmoyer@redhat.com>
Subject: Re: performance degradation on kernel upgrade (due to commit ab0a9735e06914ce4d2a94ffa41497dbc142fe7f )
Date: Fri, 21 Sep 2012 10:17:37 -0400
Message-ID: <x49r4pvlata.fsf@segfault.boston.devel.redhat.com>
References: <505C700C.3010403@elitecore.com>
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Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
To: Jagdish Motwani <jagdish.motwani@elitecore.com>
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In-Reply-To: <505C700C.3010403@elitecore.com> (Jagdish Motwani's message of
	"Fri, 21 Sep 2012 19:17:56 +0530")
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Jagdish Motwani <jagdish.motwani@elitecore.com> writes:

> Recently i upgraded my kernel from 2.6.29.6 to 2.6.35.14.
>
> After upgrading i got very poor performance on my postgre database.
[...]
> Using git bisect, i got commit ab0a9735e06914ce4d2a94ffa41497dbc142fe7f
>
> Is it a behavior change or am i missing something? Are there any
> workarounds for this?

commit ab0a9735e06914ce4d2a94ffa41497dbc142fe7f
Author: Christoph Hellwig <hch@lst.de>
Date:   Thu Oct 29 14:14:04 2009 +0100

    blkdev: flush disk cache on ->fsync

This is a data integrity fix, and you really don't want to work around
it.

Cheers,
Jeff