Re: [ck] Re: -mm merge plans for 2.6.23

[Ira Snyder <kernel@irasnyder.com>]

On Tue, 10 Jul 2007 18:14:19 -0700
Andrew Morton <akpm@linux-foundation.org> wrote:

> On Wed, 11 Jul 2007 11:02:56 +1000 "Matthew Hawkins" <darthmdh@gmail.com> wrote:
> 
> > We all know swap prefetch has been tested out the wazoo since Moses was a
> > little boy, is compile-time and runtime selectable, and gives an important
> > and quantifiable performance increase to desktop systems.
> 
> Always interested.  Please provide us more details on your usage and
> testing of that code.  Amount of memory, workload, observed results,
> etc?
> 

I often leave long compiles running overnight (I'm a gentoo user). I always have the desktop running, with quite a few applications open, usually firefox, amarok, sylpheed, and liferea at the minimum. I've recently tried using a "stock" gentoo kernel, without the swap prefetch patch, and in the morning when I get on the computer, it hits the disk pretty hard pulling my applications (especially firefox) in from swap. With swap prefetch, the system responds like I expect: quick. It doesn't hit the swap at all, at least that I can tell.

Swap prefetch definitely makes a difference for me: it makes my experience MUCH better.

My system is a Core Duo 1.83GHz laptop, with 1GB ram and a 5400 rpm disk. With the disk being so slow, the less I hit swap, the better.

I'll cast my vote to merge swap prefetch.

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