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Date:      Sun, 26 Jul 1998 13:37:03 +0200
From:      Andreas Klemm <andreas@klemm.gtn.com>
To:        dg@root.com
Cc:        Brian Feldman <green@zone.baldcom.net>, freebsd-current@FreeBSD.ORG
Subject:   Re: New LINT options: what is VM coloring?
Message-ID:  <19980726133703.A27677@klemm.gtn.com>
In-Reply-To: <199807261020.DAA07327@implode.root.com>; from David Greenman on Sun, Jul 26, 1998 at 03:20:23AM -0700
References:  <19980726112401.A5570@klemm.gtn.com> <199807261020.DAA07327@implode.root.com>

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On Sun, Jul 26, 1998 at 03:20:23AM -0700, David Greenman wrote:
> >On Sat, Jul 25, 1998 at 05:10:54PM -0700, David Greenman wrote:
> >>    Page coloring is the process of allocating pages that have physical
> >> alignment that provides optimal utilization of the memory cache. This can
> >> be a big win for direct-mapped caches (e.g. most Pentium L2 caches), but
> >> loses effectiveness with set-associative caches (e.g. Pentium Pro, which
> >> has a set size of 4).
> >
> >Do you think it would be better to turn PQ off using:
> >
> >	options	PQ_NOOPT		# No coloring
> 
>    You mean in the Pentium Pro case? No, page coloring has basically no
> overhead and can only help - even with associative caches. I think the
> "PQ_NOOPT" option is only for performance comparison/testing.

Ok, thanks !

-- 
Andreas Klemm                                http://www.FreeBSD.ORG/~andreas
     What gives you 90% more speed, for example, in kernel compilation ?
          http://www.FreeBSD.ORG/~fsmp/SMP/akgraph-a/graph1.html
             "NT = Not Today" (Maggie Biggs)      ``powered by FreeBSD SMP''

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