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From: campbell@sauron.Columbia.NCR.COM (Mark Campbell)
Newsgroups: comp.arch
Subject: Write-Back, Write-Allocate Policies
Keywords: Second-level caches
Message-ID: <2175@sauron.Columbia.NCR.COM>
Date: 6 Jun 90 15:52:47 GMT
References: <3131@goanna.cs.rmit.oz.au>
Reply-To: campbell@sauron.UUCP (Mark Campbell)
Organization: E&M-Columbia, NCR Corp, W Columbia, SC
Lines: 21

I'm looking for information on the write-allocate policies
(i.e., whether to write-allocate or not) on write-back caches.
I'm in the middle of a heated debate concerning whether it is
better to ***not*** write-allocate, specifically in a
second-level write-back cache that we're designing.

I simply don't have time to do the modeling/simulation that
would prove or disprove this (in addition to not having what
I consider to be adequate traces) and am looking for references
and/or examples in support of either mechanism.  I don't believe
that these examples have to be from second-level caches -- first-
level cache examples would be good also.

One specific question that has come up during this is whether
the RS/6000 supports write-allocate -- if I could get an answer
to this it would at least start me on my way.

Thanks.
-- 
					      Mark Campbell
					      mark.campbell@ncrcae.Columbia.NCR.COM