Subject: Re: Accounting for differences in physical memory performance
To: Jason R Thorpe <firstname.lastname@example.org>
From: Ken Seefried <email@example.com>
Date: 05/22/2002 22:27:55
Thanks Jason. Is there any doco that explains how this works, or can you
point me to a source file to plow through?
Jason R Thorpe writes:
> On Thu, May 16, 2002 at 02:27:17AM +0000, Ken Seefried wrote:
> > Is there a way, implimented or theoretical, that would maximize the
> > performance of systems with different physical memory performance
> > characteristics?
> Yes, NetBSD currently has a way to handle this (I added it a couple
> of years ago).
> What it does is break up the memory into multiple free lists, sorted in
> order of descending priority. The way this is used is that you would put
> your fastest memory on freelist 0, next fastest on freelist 1, and so on.
> The mvme68k port currently uses this facility for VME expansion memory.
> It's not perfect (in particular, if a process gets stuck with a crappy
> page, it could wind up using it for quite some time), but it seems to
> be pretty effective at minimizing the bad effects.
> -- Jason R. Thorpe <firstname.lastname@example.org>