From: Bill Davidsen <davidsen@tmr.com>
To: Guy <bugzilla@watkins-home.com>
Cc: 'Holger Kiehl' <Holger.Kiehl@dwd.de>,
'Mark Hahn' <hahn@physics.mcmaster.ca>,
'linux-raid' <linux-raid@vger.kernel.org>,
'linux-kernel' <linux-kernel@vger.kernel.org>
Subject: Re: Where is the performance bottleneck?
Date: Wed, 28 Sep 2005 16:04:47 -0400 [thread overview]
Message-ID: <433AF75F.2060208@tmr.com> (raw)
In-Reply-To: <200508302305.j7UN5bE23350@www.watkins-home.com>
Guy wrote:
>In most of your results, your CPU usage is very high. Once you get to about
>90% usage, you really can't do much else, unless you can improve the CPU
>usage.
>
That seems one of the problems with software RAID, the calculations are
done in the CPU and not dedicated hardware. As you move to the top end
drive hardware the CPU gets to be a limit. I don't remember off the top
of my head how threaded this code is, and if more CPUs will help.
I see you are using RAID-1 for your system stuff, did one of the tests
use RAID-0 over all the drives? Mirroring or XOR redundancy help
stability but hurt performance. Was the 270MB/s with RAID-0 or ???
--
bill davidsen <davidsen@tmr.com>
CTO TMR Associates, Inc
Doing interesting things with small computers since 1979
next prev parent reply other threads:[~2005-09-28 20:04 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-08-29 18:20 Where is the performance bottleneck? Holger Kiehl
2005-08-29 19:54 ` Mark Hahn
2005-08-30 19:08 ` Holger Kiehl
2005-08-30 23:05 ` Guy
2005-09-28 20:04 ` Bill Davidsen [this message]
2005-09-30 4:52 ` Guy
2005-09-30 5:19 ` dean gaudet
2005-10-06 21:15 ` Bill Davidsen
2005-08-29 20:10 ` Al Boldi
2005-08-30 19:18 ` Holger Kiehl
2005-08-31 10:30 ` Al Boldi
2005-08-29 23:09 ` Peter Chubb
[not found] ` <20050829202529.GA32214@midnight.suse.cz>
2005-08-30 20:06 ` Holger Kiehl
2005-08-31 7:11 ` Vojtech Pavlik
2005-08-31 7:26 ` Jens Axboe
2005-08-31 11:54 ` Holger Kiehl
2005-08-31 12:07 ` Jens Axboe
2005-08-31 13:55 ` Holger Kiehl
2005-08-31 14:24 ` Dr. David Alan Gilbert
2005-08-31 20:56 ` Holger Kiehl
2005-08-31 21:16 ` Dr. David Alan Gilbert
2005-08-31 16:20 ` Jens Axboe
2005-08-31 15:16 ` jmerkey
2005-08-31 16:58 ` Tom Callahan
2005-08-31 15:47 ` jmerkey
2005-08-31 17:11 ` Jens Axboe
2005-08-31 15:59 ` jmerkey
2005-08-31 17:32 ` Jens Axboe
2005-08-31 16:51 ` Holger Kiehl
2005-08-31 17:35 ` Jens Axboe
2005-08-31 19:00 ` Holger Kiehl
2005-08-31 18:06 ` Michael Tokarev
2005-08-31 18:52 ` Ming Zhang
2005-08-31 18:57 ` Ming Zhang
2005-08-31 12:24 ` Nick Piggin
2005-08-31 16:25 ` Holger Kiehl
2005-08-31 17:25 ` Nick Piggin
2005-08-31 21:57 ` Holger Kiehl
2005-09-01 9:12 ` Holger Kiehl
2005-09-02 14:28 ` Al Boldi
2005-08-31 13:38 ` Holger Kiehl
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=433AF75F.2060208@tmr.com \
--to=davidsen@tmr.com \
--cc=Holger.Kiehl@dwd.de \
--cc=bugzilla@watkins-home.com \
--cc=hahn@physics.mcmaster.ca \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-raid@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;
as well as URLs for NNTP newsgroup(s).