Re: [00/17] Large Blocksize Support V3

From: Nick Piggin
Date: Fri Apr 27 2007 - 06:22:31 EST

William Lee Irwin III wrote:
William Lee Irwin III <wli@xxxxxxxxxxxxxx> 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

SUSE Labs, Novell Inc.
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