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 08:41:35 +0100 [thread overview]
Message-ID: <20100202074135.GX13771@kernel.dk> (raw)
In-Reply-To: <e2e108261002012338j62fd1983x7f4a0122d3fd97a4@mail.gmail.com>
On Tue, Feb 02 2010, Bart Van Assche wrote:
> Hello Jens,
>
> I noticed that writing with fio to /dev/null takes much more time (220
> times more for the test below) than with dd. Did I specify the correct
> arguments to fio ? If so, is this known behavior of fio ?
>
> $ dd if=/dev/zero of=/dev/null bs=1M count=1024
> 1024+0 records in
> 1024+0 records out
> 1073741824 bytes (1.1 GB) copied, 0.121485 s, 8.8 GB/s
>
> $ fio --bs=1M --size=1G --buffered=1 --rw=write --verify=0
> --name=dev-null /dev/null
You are writing to a file named dev-null and /dev/null is being ignored
as an argument. You want a --filename=/dev/null at the end instead.
--
Jens Axboe
next prev parent reply other threads:[~2010-02-02 7:41 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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20100202074135.GX13771@kernel.dk \
--to=jens.axboe@oracle.com \
--cc=bvanassche@acm.org \
--cc=fio@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox