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Date: Tue, 23 Mar 2010 12:28:31 +0100
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Subject: Re: Poor interactive performance with I/O loads with fsync()ing
From: Pawel S <spawels13@gmail.com>
To: linux-kernel@vger.kernel.org, Ben Gamari <bgamari.foss@gmail.com>,
       tytso <tytso@mit.edu>, Nick Piggin <npiggin@suse.de>,
       Ingo Molnar <mingo@elte.hu>, Andrew Morton <akpm@linux-foundation.org>,
       Jens Axboe <jens.axboe@oracle.com>
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Hello

I am experiencing very similar issue. My system is a regular desktop
PC and it suffers from very high I/O latencies (sometimes desktop
"hangs" for eight seconds or more) when copying large files. I tried
kernels up to 2.6.34-rc2, but without luck. This issue was raised at
Phoronix forums and Arjan (from Intel) noticed it can be VM related:

http://www.phoronix.com/forums/showpost.php?p=114975&postcount=51

Here is my perf timechart where you can notice I/O "steals" CPU from
the other tasks:

http://hotfile.com/dl/30596827/ebe566b/output.svg.gz.html

Regards!

P.S. if there is some way I can help more just let me know please.