Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!ucsd!ucbvax!decwrl!jumbo!jg
From: jg@jumbo.dec.com (Jim Gettys)
Newsgroups: comp.arch
Subject: Re: i860 Dhrystones
Keywords: i860 N10 Floating Point Dhrystones
Message-ID: <13645@jumbo.dec.com>
Date: 22 Mar 89 21:32:14 GMT
References: <39388@oliveb.olivetti.com> <15475@winchester.mips.COM> <95013@sun.Eng.Sun.COM>
Reply-To: jg@jumbo.UUCP (Jim Gettys)
Organization: DEC Systems Research Center, Palo Alto
Lines: 37

In article <95013@sun.Eng.Sun.COM> cramer@sun.com (Sam Cramer) writes:
>Intel is not the only company to do this.  In the "DECstation 3100
>Performance Summary" distributed by DEC, the SINGLE integer benchmark shown
>is Dhrystone 2.1.  The text that accompanies these results contains no
>warning regarding the tendency of Dhrystone to overstate "real-world"
>integer performance.  In fact, the Dhrystone results are used to calculate
>"price-performance" ratios relative to two Sun machines (a vital metric for
>those users who spend all day running Dhrystones).  This section of the
>document (titled "CASE and Dhrystone"!) goes on to imply that these
>Dhrystone results promise good performacne on a CASE workload.
>
>It seems that when DEC acquired RISC technology from MIPS, they overlooked
>MIPS's benchmarking know-how.

If you get Mashey's latest performance brief (Issue 3.6), you will find 
pretty well complete DECstation 3100 performance numbers for his entire
suite. I sent them to John within a few days of announcement. (I ran
his suite last fall myself).

Our marketeers blew the original summary; I was to review it before it saw the
light of day, but was in the process of moving from California to 
Massachusetts.  Due to some unfortunate problems getting a copy printed
when I arrived in Cambridge, I was unable to get this problem fixed
(only one integer benchmark) in the first version of the memo  saw the 
light of day.

To first order, you can easily estimate its performance given the fact
it is a 16.667 mhz R2000.  Due to differences in the memory subsystem,
it is slightly slower than the MIPS M/120-5.

It was the typical problem of people working to deadlines overlooking things.
The summary had to make a printer's deadline for announcement.
The marketing folks promised to update the original briefs within a couple 
weeks of the original announcement; I believe you wil find that current ones 
are better.

				- Jim Gettys