From: Harald Hoyer <harald@redhat.com>
To: linux-hotplug@vger.kernel.org
Subject: Re: Update on disk IO slowdown using udev
Date: Tue, 25 May 2004 10:58:36 +0000 [thread overview]
Message-ID: <40B326DC.4060707@redhat.com> (raw)
In-Reply-To: <20040525104659.GF26696@y-boda.hpc2n.umu.se>
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Try it the other way round. I guess the data is cached :)
Use bonnie or hdparm -Tt to measure throughput!
Ake wrote:
> Hi!
> After some more experimenting i did the following,
>
> mkdir /tmpfsdev
> mount -t tmpfs tmpfs /tmpfsdev
> mknod /tmpfsdev/sdb b 8 16 (This is my test disk)
> dd if=/tmpfsdev/sdb of=/dev/null bs=8192k count=20
> 20+0 records in
> 20+0 records out
> 167772160 bytes transferred in 11.006714 seconds (15242711 bytes/sec)
>
> mkdir /rawdev
> mknod /rawdev/sdb b 8 16
> dd if=/rawdev/sdb of=/dev/null bs=8192k count=20
> 20+0 records in
> 20+0 records out
> 167772160 bytes transferred in 1.668631 seconds (100544793 bytes/sec)
>
>
> So tmpfs is the culprit.
> So, yes using udev i DO get a slowdown due to its use of tmpfs.
>
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next prev parent reply other threads:[~2004-05-25 10:58 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-25 10:46 Update on disk IO slowdown using udev Ake
2004-05-25 10:58 ` Harald Hoyer [this message]
2004-05-25 11:14 ` Ake
2004-05-25 12:01 ` Harald Hoyer
2004-05-25 12:05 ` Harald Hoyer
2004-05-25 12:49 ` Harald Hoyer
2004-05-25 18:01 ` Ake
2004-05-25 18:19 ` Oliver Neukum
2004-05-25 18:42 ` Olaf Hering
2004-05-25 19:58 ` Oliver Neukum
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