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From: xxremak@csduts1.lerc.nasa.gov (David A. Remaklus)
Newsgroups: comp.parallel
Subject: Acceptable efficiency factors
Message-ID: <9508@hubcap.clemson.edu>
Date: 29 Jun 90 13:34:31 GMT
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Approved: parallel@hubcap.clemson.edu

In a recent conversation with some colleagues of mine at the Ames NAS
facility concerning parallel processing, they mentioned their experiences
porting a code to the Intel i860 hybercube located there (128 nodes,
7.5 gigaFLOPS peek).  On this particular code they were able to
achieve about 300 MFLOPS for an efficiency factor of about 2.5%.  This
low efficiency factor didn't seem to bother them but it sure bothered
me.  Other colleagues of ours at the United Technologies Research Center
in East Hartford, CT ported similar codes to their 1/4 CM-2 and achieved
anywhere from 600 to 800 MFLOPS for an effiency factor of more than 50%.

It is our contention that it is necessary to achieve an efficiency factor
of at least 50% before the particular implementation of the code can be
considered appropriate for execution on that parallel processor system.
What are your opinions on this matter?  Are there any published papers
that deal with this subject?

Dave R.

--
David A. Remaklus
NASA Lewis Research Center
Cleveland, Ohio 44135
xxremak@csduts1.lerc.nasa.gov