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From: gl8f@astsun7.astro.Virginia.EDU (Greg Lindahl)
Newsgroups: comp.benchmarks
Subject: Re: Anyone volunteer to do Fortran vs. C on SPECmarks?
Message-ID: <1990Dec19.160247.13582@murdoch.acc.Virginia.EDU>
Date: 19 Dec 90 16:02:47 GMT
References: <111621@convex.convex.com> <1990Dec19.032301.4449@murdoch.acc.Virginia.EDU> <15180@ogicse.ogi.edu>
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In article <15180@ogicse.ogi.edu> borasky@ogicse.ogi.edu (M. Edward Borasky) writes:

>>Anyone volunteer to run SPEC through f2c and report times for Fortran
>>and C on a variety of boxes?
>Dumb idea!  There are a number of factors that need to be isolated:

Bzzt. I did not claim I could isolate the factors -- I just want to
see, in general, what the total factor (f2c + relative fortran/cc
compiler + inherant fortran superiority) is.

With any benchmark like this, all you have to do is remember what
you're measuring. Since no numbers of this sort exist yet, I think
SPEC would make a great first try.

On to your issues:

>1. How efficient is the "C" code that f2c produces?

To eye, it looks good.

>2. How efficient is the machine code that the target "C" and FORTRAN
>compilers produce?

This will be tested. I would like to know if a particular vendor's
FORTRAN or C is relatively poor. The vendor might want to know if he
could use f2c to get a faster SPECmark ;-)

>3. How well-suited is the code to the architecture of the boxes in the
>first place, etc.

This I understand, I think. Interpreting SPEC always requires some
thought as to what sorts of operations the benchmark does. No new
issue there.

>As a first cut, the Livermore FORTRAN Kernels (LFK) benchmark is
>available in both FORTRAN and C.  The C translation was hand-coded
>with loving care by Greg Astfalk (then of AT&T, now of Convex.)  It is
>NOT repeat NOT a coincidence that [...]

I want to test a variety of codes, mainly to find out if my guess
(that aliasing information is important) is true. Finding that one
particular benchmark (LFK) is comparable in speed is not interesting
to me. I'd be very interested at seeing what's comparable and what's
not.

>  I would expect similar speeds (FORTRAN vs. "C") on
>the LFK benchmark on RISC machines.

I'd like to see all of SPEC, so we're more likely to be surprised.