Date: Mon, 27 Jul 1998 18:05:17 -0500 (EST) From: "John S. Dyson" <dyson@iquest.net> To: tlambert@primenet.com (Terry Lambert) Cc: dyson@iquest.net, dfr@nlsystems.com, tlambert@primenet.com, roberto@keltia.freenix.fr, freebsd-current@FreeBSD.ORG Subject: Re: New LINT options: what is VM coloring? Message-ID: <199807272305.SAA02258@dyson.iquest.net> In-Reply-To: <199807272023.NAA20781@usr08.primenet.com> from Terry Lambert at "Jul 27, 98 08:23:32 pm"
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Terry Lambert said: > > For two level caches, the coloring should work fine. However, it is > > problematical with 3-level alpha caches. My guess is that one would > > want to page-color for the 2nd and 3rd level caches, but of course, > > you might want to experiment. It is critical to color for the larger > > cache. To color for all three caches, you could just expand the > > coloring scheme in FreeBSD. I don't know if it is the right approach > > though. > > The Digital literature suggests for small enough working sets, putting > the entire working set into L1 cache and keeping it there. I don't > know how you would ensure this if you were allowing interrupts and > drivers to run, except to minimize the use of seperate stacks as > much as possible, and reduce the amount of auto data usage and function > call depth for interrupt code as much as possible. > > The method they state they use in order to do this is "page coloring" > of the L1 cache. > > This is from the Digitasl UNIX 2.0 release notes. > But - but - but, the L1 cache is small!!! Is our terminology mixed-up? On X86en, L2 cache is the big one. I thought that on an Alpha, the L3 cache is the big one. I don't know how one would fit the working set into a 16K or even 128K cache?!?!?!? I can understand fitting the working set into a 1M -> 4M L3 cache though :-). -- John | Never try to teach a pig to sing, dyson@iquest.net | it makes one look stupid jdyson@nc.com | and it irritates the pig. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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