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Re: Second level cache?

To: riscy@pyramid.com
Subject: Re: Second level cache?
From: Tommy Thorn <tthorn@daimi.aau.dk>
Date: Wed, 11 Aug 1993 12:02:49 +0200
References: <199308101106.AA17966@romeo.cs.Colorado.EDU> <9308101816.AA16534@sword.eng.pyramid.com>
Reply-to: Tommy.Thorn@daimi.aau.dk
Reply-to: riscy@pyramid.com
Sender: owner-riscy@pyramid.com
Neil Russell writes:
 > What I understand is that the ARC chipset supports a secondary cache
 > similar to the way it does for the 486.  It is not necessary to use
 > the cache support signals from the R4k to have a secondary cache, although
 > it may mean that this cache will take two cycles to access data where
 > the R4000SC cache would take one.  This may not be great, but it is still
 > better than the cycles required to get data from DRAM.

Andreas Busse writes:
 > 5. The R4200 ***DOES NOT*** support 2nd level cache. The Blockdiagram
 >    of ARCset shows no 2nd level cache, and there's ***NO SUPPORT*** at all.


 > Finally, I simply don't understand why this discussion came up.
 > I thought our goal was to design and produce a board with very good
 > price/performance relation. Although the price of the ARCset isn't
 > clear at the moment (which is not my or our fault, but NEC's) it seems
 > that this is what we are looking for. It offers more speed than
 > a R3081 solution probably for only few $s more.

I suppose the discussion came becourse there is evidence that cache
size can influence performens (big news ;^) It is then a natural
question to ask "Can we have more? How much will it cost?" That the
ARCset didn't support it was/is non-obvious for the most of us. (Given
that most of us don't have any info on the ARCset besides what's
revealed in this forum.)

 > If you all insist on a 2nd level cache design, we should forget
 > about the ARCset. That means in turn that we should forget about
 > having a design within the next 12 months. I'm not sure what then
 > happens to the group...

Given this, we proberly don't wan't 2nd level cache, but don't flame
us for having the discussion.

/Tommy Thorn


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