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Date: Sat, 6 Nov 2010 12:10:42 -0700
From: Arjan van de Ven <arjan@infradead.org>
Subject: Re: 2.6.36 io bring the system to its knees
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To: Sanjoy Mahajan <sanjoy@olin.edu>
Cc: Dave Chinner <david@fromorbit.com>, Jesper Juhl <jj@chaosbits.net>, Chris Mason <chris.mason@oracle.com>, Ingo Molnar <mingo@elte.hu>, Pekka Enberg <penberg@kernel.org>, Aidar Kultayev <the.aidar@gmail.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Linus Torvalds <torvalds@linux-foundation.org>, Andrew Morton <akpm@linux-foundation.org>, Jens Axboe <axboe@kernel.dk>, Peter Zijlstra <a.p.zijlstra@chello.nl>, Nick Piggin <npiggin@suse.de>, Thomas Gleixner <tglx@linutronix.de>, Ted Ts'o <tytso@mit.edu>, Corrado Zoccolo <czoccolo@gmail.com>, Shaohua Li <shaohua.li@intel.com>, Steven Barrett <damentz@gmail.com>
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On Fri, 5 Nov 2010 08:48:13 -0400
Sanjoy Mahajan <sanjoy@olin.edu> wrote:

> Dave Chinner <david@fromorbit.com> wrote:
> 
> > I think anyone reporting a interactivity problem also needs to
> > indicate what their filesystem is, what mount paramters they are
> > using, what their storage config is, whether barriers are active or
> > not, what elevator they are using, whether one or more of the
> > applications are issuing fsync() or sync() calls, and so on.
> 
> Good idea.  
> 
> The filesystems are all ext3 with default mount parameters.  The
> dmesgs say that the filesystems are mounted in ordered data mode and
> that barriers are not enabled.

btw few more things to try (from my standard rc.local script):

echo 4096 > /sys/block/sda/queue/nr_requests

for i in `pidof kjournald` ; do ionice -c1 -p $i ; done

echo 75 >  /proc/sys/vm/dirty_ratio


(replace sda with whatever your disk is of course)

-- 
Arjan van de Ven 	Intel Open Source Technology Centre
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org

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