Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!mcvax!hp4nl!philapd!ssp1!roelof
From: roelof@idca.tds.PHILIPS.nl (R. Vuurboom)
Newsgroups: comp.arch
Subject: Re: MIPS/MFLOPS ratio
Summary: Balance
Message-ID: <140@ssp1.idca.tds.philips.nl>
Date: 29 Jun 89 12:06:25 GMT
References: <596@megatek.UUCP>
Organization: Philips Telecommunication and Data Systems, The Netherlands
Lines: 41

In article <596@megatek.UUCP> mark@megatek.UUCP () writes:
>performance. A little paper design for a SPARC system using the latest
>Cypress IU and FPC/FPU gets me a MIPS/MFLOPS ratio of about 10.
>
>This seems a little out of whack... it seems that older scientific
>processors had ratios in the 3-4 range.
>
>Looking a published info on MIPS, and some hand waving gets me a ratio
>of about 5-6, better but still slow (an aside: what are the MIPS guys 
>doing to get the speeds up higher than the SPARC guys? compilers?)
>
>Why is the floating point lagging integer performance so much? What is
>being done to get this back in balance?
>
Question is: Is a 3-4 MIPS/MFLOPS balanced?

To avoid the eternal "it depends on the application" suppose we agree 
that for example the SPEC Benchmark suite is a representative model of
our application.

Can anybody give some sort of (simplistic, I know) rules-of-thumb about 
MIPS/MFLOPS real estate ratios as a function of performance. Something like:
increasing MFLOPS performance x% would mean y% more real estate needed,
the corresponding real estate reduction for the IU (and rest) would probably 
mean z% less MIPS. 

By varying the MIPS/MFLOPS ratios (given a fixed amount of silicon) a
ratio best tuned to the Suite could be calculated using the agreed
upon weightings etc.  

Since we (one sidedly) agreed that the suite was a representative model of 
our application world this could be a quasi-objective determination of
what is a "balanced" processor.

Flames anyone?


Disclaimer: Opinions are really just onions and pi.
-- 
Roelof Vuurboom  SSP/V3   Philips TDS Apeldoorn, The Netherlands   +31 55 432226
domain: roelof@idca.tds.philips.nl             uucp:  ...!mcvax!philapd!roelof