Path: utzoo!attcan!uunet!lll-winken!sol.ctr.columbia.edu!emory!hubcap!xxremak
From: xxremak@csduts1.lerc.nasa.gov (David A. Remaklus)
Newsgroups: comp.parallel
Subject: Re: Acceptable efficiency factors
Message-ID: <9684@hubcap.clemson.edu>
Date: 13 Jul 90 19:35:11 GMT
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Reply-To: csduts1!xxremak@uunet.UU.NET (David A. Remaklus)
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In article <9661@hubcap.clemson.edu> dfk@grad13.cs.duke.edu (David F. Kotz) writes:
>What is difficult about programming many MIMD (or SIMD) systems is to
>make an *efficient* program (the original point of this thread of
>discussion).  Just getting your program to run is not always that
>hard, although of course some systems/languages are easier than others
>in this respect. To make an efficient program, unfortunately, one must
>usually pay attention to architectural details. 
>
After the original posting, I received a number of comments by email.  It
seems that we all have different definitions for efficiency as it applies
to parallel processing.  I think the core issue that needs to be
considered (which is related to efficiency) is the determination of the
"appropriateness" of executing a given application/algorithm for
a given architecture and parallel system.  For example, few (I would think)
would argue that it is inappropriate to run an entirely or predominately
scalar code on a CRAY supercomputer.

I mean it all gets down to whether or not the application/algorithm can
take advantage of the resources presented to it by the architecture/machine.
If it can't, then it doesn't belong there.

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