From owner-cvs-all  Fri Aug 13 13:34:42 1999
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Date: Fri, 13 Aug 1999 15:33:31 -0500
From: Alan Cox <alc@cs.rice.edu>
To: Hidetoshi Shimokawa <simokawa@sat.t.u-tokyo.ac.jp>
Cc: rgrimes@gndrsh.aac.dev.com, cvs-committers@freebsd.org,
	cvs-all@freebsd.org
Subject: Re: cvs commit: src/sys/vm vm_page.h
Message-ID: <19990813153331.C26372@nonpc.cs.rice.edu>
References: <199908122116.OAA56955@freefall.freebsd.org> <199908131458.HAA01346@gndrsh.aac.dev.com> <19990813140128.C27982@cs.rice.edu> <14260.30905.562825.38243A@ett.sat.t.u-tokyo.ac.jp>
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In-Reply-To: <14260.30905.562825.38243A@ett.sat.t.u-tokyo.ac.jp>; from Hidetoshi Shimokawa on Sat, Aug 14, 1999 at 04:57:45AM +0900
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On Sat, Aug 14, 1999 at 04:57:45AM +0900, Hidetoshi Shimokawa wrote:
> ...
>
> As for 21164 Alpha, it has 96KB 3-way L2 cache.
> So it needs only 4 (= 96KB / 8KB / 3) colors.
> 
> My Alpha box has 4MB direct-map L3 cache and
> it needs 4MB / 8KB = 512 colors. I have the following entries in my
> vm_page.h
> 

I am afraid that the current implementation of page coloring doesn't
scale very well to such a large number of colors, especially if you
don't have an extremely large amount of physical memory.  Far too often,
it's unable to allocate a page of the appropriate color.  Even with
just 8 colors on a machine with 320MB of physical memory, the number
of times that coloring fails during a "make world" is extraordinary.

Bruce Evans and I are looking into this...if someone with an Alpha
has time to help out that could be useful.

	Alan


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