Path: utzoo!attcan!uunet!timbuk!juniper09!ds
From: ds@juniper09.cray.com (David Sielaff)
Newsgroups: comp.sys.super
Subject: Re: Cray vs. PC Benchmark
Message-ID: <093631.7171@timbuk.cray.com>
Date: 22 Oct 90 14:48:10 GMT
References: <38230@ut-emx.uucp> <97@garth.UUCP>
Organization: Cray Research, Inc., Eagan, MN
Lines: 44

In article <97@garth.UUCP> fouts@bozeman.bozeman.ingr.UUCP (Martin Fouts) writes:
> [...stuff...]
>But on a more serious front:  Certain workstations achieve floating
>point performance within 10% of a Cray on real applications.  If you
>have to split your Cray 10 ways, the workstation is a win.

One of the main thrusts of my original posts was to try to expain reasons
not to say "as compared to a Cray", etc.  That's like saying "My laptop
is faster than an IBM!"  Which IBM?  How many years old?  Doing What?
I'm not trying to deny that you have certain benchmark results, but
throwing around comments like "as compared to a Cray" is just a short
distance this side of meaningless.  I also don't believe that a Cray
is the appropriate tool for all applications.  Cray machines have been
designed with certain ideas mind, like fast processor speed, fast vector
processing, large fast memory (both main & secondary), etc.  If you need
a machine like that, perhaps a Cray (Y-MP, so I don't get flamed for
not specifying ;-) ) is what you should use.  

>>Plus the fact that the /4 part of the machine
>>type means that the machine has four CPU's, which is meaningless for this
>>benchmark.  All of the timings are for one processor.
>>>   [... stuff ...]
>>And finally, Cray's are designed
>>for floating point, not integer arithmetic, so a lot of extra conversions
>>from integer format to floating point format (and back) will need to be
>>done.
>
>Most user codes only run on one processor, by the way.

True, but my point was that if you are going to specify that your benchmark
is against a four processor machine, either run it using all four processors,
or specify that it was run on one processor.

>>> Listen to this man.  He may not be marketing (virtue or vice?), but he is
>>> enlightened.. ;)
>
>>> 	=-ddt->
>
>There are many paths to enlightenment.
>--
>Martin Fouts
>

Dave Sielaff