From: Jens Axboe <jaxboe@fusionio.com>
To: "N. Harake" <hussein@cscs.ch>
Cc: "fio@vger.kernel.org" <fio@vger.kernel.org>
Subject: Re: memory caching
Date: Tue, 15 Mar 2011 21:28:14 +0100 [thread overview]
Message-ID: <4D7FCBDE.2080206@fusionio.com> (raw)
In-Reply-To: <C9A519EC.108B4%hussein@cscs.ch>
On 2011-03-15 13:36, N. Harake wrote:
>
> I noticed when I am using --sync=1, IOPS go down to 15K and throughput to
> 53MB (That�s horrible for the HW I am using), removing --sync I got 150K
> IOPS and almost 800MB, which make more sense. What does --sync does, and
> hope what I am doing should be enough to avoid any kind of memory caching..
>
> Regards
> H. N. Harake
>
> fio --name=job --directory=/lvm --size=1G --iodepth=1 --sync=1
> --filesize=1G --direct=1 --numjobs=64 --bs=4096 --rw=randwrite
> --group_reporting
If your goal is to maximize iops for testing, use the raw block device.
Use direct=1, and ioengine=libaio. Set depth large, ala:
--iodepth=128 --iodepth_batch_complete=8 --iodepth_batch_submit=8
--
Jens Axboe
next prev parent reply other threads:[~2011-03-15 20:28 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-15 8:27 memory caching N. Harake
2011-03-15 12:36 ` N. Harake
2011-03-15 20:28 ` Jens Axboe [this message]
2011-03-15 20:46 ` N. Harake
2011-03-15 20:55 ` Jens Axboe
2011-03-15 20:54 ` N. Harake
2011-03-15 20:56 ` Jens Axboe
2011-03-15 20:20 ` Jens Axboe
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