From: Olaf Hering <olh@suse.de>
To: "Richard B. Johnson" <root@chaos.analogic.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: very low performance on SCSI disks if device node is in tmpfs
Date: Tue, 25 May 2004 21:34:58 +0200 [thread overview]
Message-ID: <20040525193458.GA21120@suse.de> (raw)
In-Reply-To: <Pine.LNX.4.53.0405251457450.582@chaos>
On Tue, May 25, Richard B. Johnson wrote unrelated stuff:
did you actually try it?
(none):~ # /usr/bin/time dd if=/dev/sdb bs=1M count=123 of=/dev/null
123+0 records in
123+0 records out
0.00user 0.75system 0:17.13elapsed 4%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+426minor)pagefaults 0swaps
(none):~ # /usr/bin/time dd if=/dev/sdb bs=1M count=123 of=/dev/null
123+0 records in
123+0 records out
0.00user 0.74system 0:15.66elapsed 4%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+426minor)pagefaults 0swaps
(none):~ # /usr/bin/time dd if=/dev/sdb bs=1M count=123 of=/dev/null
123+0 records in
123+0 records out
0.00user 0.78system 0:15.67elapsed 5%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+426minor)pagefaults 0swaps
(none):~ # /usr/bin/time dd if=/tmp/sdb bs=1M count=123 of=/dev/null
123+0 records in
123+0 records out
0.00user 0.47system 0:06.44elapsed 7%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+426minor)pagefaults 0swaps
(none):~ # /usr/bin/time dd if=/tmp/sdb bs=1M count=123 of=/dev/null
123+0 records in
123+0 records out
0.00user 0.47system 0:06.44elapsed 7%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+426minor)pagefaults 0swaps
(none):~ # /usr/bin/time dd if=/tmp/sdb bs=1M count=123 of=/dev/null
123+0 records in
123+0 records out
0.00user 0.50system 0:06.44elapsed 7%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+426minor)pagefaults 0swaps
--
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next prev parent reply other threads:[~2004-05-25 19:37 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-25 18:47 very low performance on SCSI disks if device node is in tmpfs Olaf Hering
2004-05-25 19:14 ` Richard B. Johnson
2004-05-25 19:34 ` Olaf Hering [this message]
2004-05-25 19:44 ` Richard B. Johnson
2004-05-25 20:02 ` Oliver Neukum
2004-05-25 21:48 ` Andrew Morton
2004-05-25 21:57 ` Richard B. Johnson
2004-05-25 21:59 ` Andrew Morton
2004-05-25 22:41 ` Andrew Morton
2004-05-26 0:05 ` Linus Torvalds
2004-05-26 0:10 ` viro
2004-05-26 0:14 ` Andrew Morton
2004-05-26 9:53 ` Olaf Hering
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