From: Jens Axboe <jens.axboe@oracle.com>
To: Bart Van Assche <bvanassche@acm.org>
Cc: fio@vger.kernel.org
Subject: Re: Writing to /dev/null with fio
Date: Tue, 2 Feb 2010 10:08:13 +0100 [thread overview]
Message-ID: <20100202090813.GC13771@kernel.dk> (raw)
In-Reply-To: <20100202085305.GA13771@kernel.dk>
On Tue, Feb 02 2010, Jens Axboe wrote:
> So the same for 512b buffers, fio is much quicker for 64k (must be due
> to proper aligning). I'll boot the big box and see what that says.
Same set of tests, only this time using a box with a lot more CPUs and
memory bandwidth. 'fio+' is fio with the fix for eliminating lseek(),
'fio' is without that fix.
App bs bandwidth
-----------------------------------------
dd 512 1.7GB/sec
fio 512 1.2GB/sec
fio+ 512 1.5GB/sec
dd 4k 6.6GB/sec
fio 4k 10.3GB/sec
fio+ 4k 12.4GB/sec
So dd is still faster for small blocks sizes, as expected. I don't think
there's any low hanging fruit left for fixing that. At 4k and higher the
impact should be neglible, so I don't think it's a huge problem. Most
real world testing is 4k or above.
--
Jens Axboe
prev parent reply other threads:[~2010-02-02 9:08 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-02 7:38 Writing to /dev/null with fio Bart Van Assche
2010-02-02 7:41 ` Jens Axboe
2010-02-02 8:01 ` Bart Van Assche
2010-02-02 8:19 ` Jens Axboe
2010-02-02 8:24 ` Bart Van Assche
2010-02-02 8:31 ` Jens Axboe
2010-02-02 8:53 ` Jens Axboe
2010-02-02 9:06 ` Bart Van Assche
2010-02-02 9:08 ` Jens Axboe [this message]
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