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]
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