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Date: Sat, 18 Jul 2009 16:39:55 +0200
From: Jens Axboe <jens.axboe@oracle.com>
Subject: Re: fio mmap writes much slower than default writes
Message-ID: <20090718143955.GJ4148@kernel.dk>
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To: Richard Kennedy <richard@rsk.demon.co.uk>
Cc: fio <fio@vger.kernel.org>

On Sat, Jul 18 2009, Richard Kennedy wrote:
> Disk stats (read/write):
>   dm-0: ios=3571/9894, merge=0/0, ticks=25884/31650, in_queue=511733, util=96.46%, aggrios=0/0, aggrmerge=0/0, aggrticks=0/0, aggrin_queue=0, aggrutil=0.00%

If you look at the disk stats, it also shows a considerable amount of
reads. So I'm guessing that you need pre_read=1 to get the same sort of
results.

-- 
Jens Axboe