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From: apb@boole.acc.Virginia.EDU (Alan P. Batson)
Newsgroups: comp.sys.super
Subject: Re: Cray vs. PC Benchmark
Message-ID: <1990Oct15.101605.11156@murdoch.acc.Virginia.EDU>
Date: 15 Oct 90 10:16:05 GMT
References: <38230@ut-emx.uucp> <42097@mips.mips.COM>
Sender: news@murdoch.acc.Virginia.EDU
Organization: University of Virginia
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In article <42097@mips.mips.COM> mash@mips.COM (John Mashey) writes:
>In article <38230@ut-emx.uucp> ddt@ccwf.cc.utexas.edu (David Taylor) writes:
>>In article <161512.23931@timbuk.cray.com> ds@juniper09.cray.com (David Sielaff) writes:
>>>In article <1990Oct9.192119.4453@murdoch.acc.Virginia.EDU> clc5q@shamash.cs.Virginia.EDU (Clark L. Coleman) writes:
>>
>>>>I realize that Dhrystones are not meaningful for supercomputer applications,
>>>>but I thought that the scalar integer MIPS of a Cray would still exceed a
>>>>PC.
>Dhrystone is not geenrally meaningful these days, period.
>It is well-known that compiler hacks exist (around the strcpy call),
>that can boost apparent performance 30-40%, without affecting real programs
>in any noticable fashion.  IT almost always overstates performance relative
>to a VAX, which is why it is so popular among some computer companies :-)
>...

While it is indeed true that a high Dhrystone value doesn't mean much
at all, it is certainly the case that a system giving a LOW value
has some kind of weakness. Like one of our better-known Crayettes.....

Alan P. Batson                     Academic Computing Center
apb@virginia.edu                   University of Virginia
(804) 924-0610                     Gilmer Hall
                                   Charlottesville, VA 22903