Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!bbn!apple!versatc!mips!mash
From: mash@mips.COM (John Mashey)
Newsgroups: comp.arch
Subject: Re: Register Scoreboarding
Message-ID: <19689@winchester.mips.COM>
Date: 14 May 89 18:40:44 GMT
References: <24821@lll-winken.LLNL.GOV> <28200311@mcdurb>
Reply-To: mash@mips.COM (John Mashey)
Organization: MIPS Computer Systems, Sunnyvale, CA
Lines: 20

In article <28200311@mcdurb> aglew@mcdurb.Urbana.Gould.COM writes:

>What about block copies (like, copying I/O data from kernel to user)?
>(SUNOS 4 mapped files reduce this a bit)
>
>Sometimes there's no substitute for having a good, interleaved,
>memory system (which I believe MIPS does(?))

The older machines had various flavors of interleaving.
The M/2000 uses 2-way interleaving per memory board to sustain
read traffic of 1 word/cycle, or write traffic of 1 word/2 cycles.
Bcopy works fine; there's enough reading to do to not have an
issue with write stalls.  The only case that write-stalls much is
bzero, because there isn't much else to do; the only answer to that is
a more expensive memory system, which of course is possible.
-- 
-john mashey	DISCLAIMER: <generic disclaimer, I speak for me only, etc>
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