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Message-ID: <4631CECF.4030301@yahoo.com.au>
Date: Fri, 27 Apr 2007 20:22:07 +1000
From: Nick Piggin <nickpiggin@...oo.com.au>
To: William Lee Irwin III <wli@...omorphy.com>
CC: "Eric W. Biederman" <ebiederm@...ssion.com>,
Christoph Lameter <clameter@....com>,
linux-kernel@...r.kernel.org, Mel Gorman <mel@...net.ie>,
David Chinner <dgc@....com>,
Jens Axboe <jens.axboe@...cle.com>,
Badari Pulavarty <pbadari@...il.com>,
Maxim Levitsky <maximlevitsky@...il.com>
Subject: Re: [00/17] Large Blocksize Support V3
William Lee Irwin III wrote:
> William Lee Irwin III <wli@...omorphy.com> writes:
>
>>>In memory as on disk, contiguity matters a lot for performance.
>
>
> On Thu, Apr 26, 2007 at 12:21:24PM -0600, Eric W. Biederman wrote:
>
>>Not nearly so much though. In memory you don't have seeks to avoid.
>>On disks avoiding seeks is everything.
>
>
> I readily concede that seeks are most costly. Yet memory contiguity
> remains rather influential.
>
> Witness the fact that I'm now being called upon a second time to
> adjust the order in which mm/page_alloc.c returns pages for the
> sake of implicitly establishing IO contiguity (or otherwise
> determining why things are coming out backward now).
Just a random aside question... doesn't Oracle db do direct IO from
hugepages?
--
SUSE Labs, Novell Inc.
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