From: Robert Hancock <hancockrwd@gmail.com>
To: "Brian D. McGrew" <brian@visionpro.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Slow Disk I/O
Date: Fri, 28 May 2010 18:01:27 -0600 [thread overview]
Message-ID: <4C005957.9040408@gmail.com> (raw)
In-Reply-To: <C8255AC1.18B68%brian@visionpro.com>
On 05/28/2010 12:34 PM, Brian D. McGrew wrote:
> Good morning All!
>
> I¹m running CentOS 5.4 x86_64 on a Dell T5500 with 3GB || 12GB or RAM. I¹m
> running a 2.6.18-128.el5 kernel. There is a 500GB SATA drive connected to
> the onboard SATA controller. I can reproduce this problem with CentOS 5.4
> i386 on the Dell T5500, T5400 and Optiplex 740¹s.
>
> So now, on to the problem... In our software, we¹re reading in 5MP image
> files in the neighborhood of 500 to 1500 files at a time. Just a simple
> for() loop, open, read, close... Nothing fancy...
>
> When I have 3GB of RAM in the system, life is good.. Each read takes 8 to
> 10ms... This is a good thing!
>
> If I bump the memory up to 12GB, all of the reads are now taking 150 to
> 200ms.
>
> My default, va.swappines to set to 60... If I decrease this number, the
> problem gets much worse. If I up va.swappines to 100, the problem gets a
> little better, but not a whole lot.
>
> What should I be looking at???
Can you post the dmesg output and the contents of /proc/mtrr?
prev parent reply other threads:[~2010-05-29 0:01 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-28 18:34 Slow Disk I/O Brian D. McGrew
2010-05-29 0:01 ` Robert Hancock [this message]
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=4C005957.9040408@gmail.com \
--to=hancockrwd@gmail.com \
--cc=brian@visionpro.com \
--cc=linux-kernel@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