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From: davidsen@sixhub.UUCP (Wm E. Davidsen Jr)
Newsgroups: comp.benchmarks
Subject: Re: PERFECT rumor
Message-ID: <2722@sixhub.UUCP>
Date: 23 Dec 90 17:24:05 GMT
References: <6439@mace.cc.purdue.edu> <1990Dec19.190758.8285@ux1.cso.uiuc.edu>
Reply-To: davidsen@sixhub.UUCP (bill davidsen)
Organization: *IX Public Access UNIX, Schenectady NY
Lines: 36

In article <1990Dec19.190758.8285@ux1.cso.uiuc.edu> conte@crest.crhc.uiuc.edu (Tom Conte) writes:

| etc. (including hand modification). It's part of the philosophy: monkey
| around with the code as much as you wish to make it run well on your machine,
| just make sure the results are the same.  For me, this makes PERFECT club
| numbers rather hard to interpret.

  I think that both the idea of running the unchnaged code on various
machines and running the code tuned any old way which still produces the
right answer are both valid.

  By running unchanged code you get a good idea of how well the compiler
and CPU work in solving problews coded in the obvious way. Since this is
the lowest cost in programming time, most people would like to get good
results without hand coding. Some so-called FORTRAN programs we run on
the Cray and Convex systems are about as portable as assembler!

  By tuning the code to get the most from the machine, you get an idea
of the hardware limits of the system. If you are pushing the limits of
what can be computed within the limts of your budget or lifespan, you
are interested in this.

  Finally the amount of improvement caused by tuning the source tells
you how well the compiler works. If you get a big improvement, it
usually means the compiler is not doing a good job (note usually).

  I find all this information useful, and the baseline vs tuned is
certainly a useful data set to me. I would like to see a third set, from
untouched source which has been broken into separate files to allow
various compilation option to be used as needed, but this is certainly
not needed, just interesting.
-- 
bill davidsen - davidsen@sixhub.uucp (uunet!crdgw1!sixhub!davidsen)
    sysop *IX BBS and Public Access UNIX
    moderator of comp.binaries.ibm.pc and 80386 mailing list
"Stupidity, like virtue, is its own reward" -me