*BSD News Article 28279


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From: John Dyson <dysonj@delphi.com>
Newsgroups: comp.os.386bsd.questions
Subject: Re: linux's I/O calls faster than NetBSD's ?
Date: Fri, 11 Mar 94 01:56:19 -0500
Organization: Delphi (info@delphi.com email, 800-695-4005 voice)
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Message-ID: <5w-r3h7.dysonj@delphi.com>
References: <2lhv9r$pbt@homea.ensta.fr> <CMFvuI.IHu@cnsnews.Colorado.EDU>
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X-To: -=Runaway Daemon=- <frechett@benji.Colorado.EDU>

-=Runaway Daemon=- <frechett@benji.Colorado.EDU> writes:
 
>I'm not sure if I like unified caches yet as I've seen them seriously
>cripple an Alpha box.  Having not spent much time in Linux I can't
>say if it's better than OSF/1's implementation or not.
 
On FreeBSD, we will be implementing a unified cache (in progress now.)  There
are a couple of things that can really cause problems.  We will not simply
allow the buffer cache to overrun the rest of memory, and also we will not
let lots of dirty buffers sandbag the disk drives.  There will be a
signficant performance improvement because of some of the leveraging of the
VM system against the problem also.  If anyone has comments on the problems
or difficulties with unified caches, let me know.  I do have a variable
size buffer cache version of vfs__bio that I wrote about a year ago, and
it could be coerced into causing problems (hope to avoid in the new
unified code.)
 
John
dyson@implode.root.com