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From: Ray Lee <ray-lk@madrabbit.org>
To: Clint Byrum <cbyrum@spamaps.org>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: 2.6 vm/elevator loading down disks where 2.4 does not
Date: Wed, 09 Jun 2004 18:03:05 -0700	[thread overview]
Message-ID: <1086829384.13085.10.camel@orca.madrabbit.org> (raw)
In-Reply-To: <2c0942db04060917542cb15077@mail.gmail.com>

> Upon investigation, we saw that the 2.6 box was reading from the disk
> about 5 times as much as 2.4.

I don't think this will account for the entire change in disk activity,
but 2.6.7-pre? contains a fix for the read ahead code to prevent it from
reading extra sectors when unneeded.

The fix applies to 'seeky database type loads' which...

> The data access patterns are generally "search through index files in
> a tree-walking type of manner, then seek to data records in data
> files."

...sounds like it may apply to you.

So, if you and your server have some time, you might try 2.6.7rc3 and
see if it changes any of the numbers.

Ray Lee


  parent reply	other threads:[~2004-06-10  1:03 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-06-08 19:51 2.6 vm/elevator loading down disks where 2.4 does not Clint Byrum
2004-06-09 23:25 ` Andrew Morton
2004-06-11 16:45   ` Clint Byrum
     [not found] ` <2c0942db04060917542cb15077@mail.gmail.com>
2004-06-10  1:03   ` Ray Lee [this message]
2004-06-10  6:03     ` Clint Byrum
2004-06-10  6:10       ` William Lee Irwin III

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