Re: [00/17] Large Blocksize Support V3

[Nick Piggin]

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
hugepages?

--
SUSE Labs, Novell Inc.
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