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From: clif@intelca.UUCP
Newsgroups: comp.arch,comp.sys.nsc.32k
Subject: Re: Re: the NS32532
Message-ID: <2577@intelca.UUCP>
Date: Mon, 13-Apr-87 14:03:18 EST
Article-I.D.: intelca.2577
Posted: Mon Apr 13 14:03:18 1987
Date-Received: Wed, 15-Apr-87 04:06:03 EST
References: <4190@nsc.nsc.com> <951@moscom.UUCP>
Organization: Intel, Santa Clara, Ca.
Lines: 46
Xref: utgpu comp.arch:862 comp.sys.nsc.32k:58

> In article <4190@nsc.nsc.com> roger@nsc.nsc.com (Roger Thompson) writes:
> >	32332 @ 15 MHZ version 1.0 optimized ............ 3943.5
> >	32332 @ 15 MHZ version 1.1 optimized ............ 3183.0
> >	32332 @ 15 MHZ version 1.1 no global opt......... 2724.0
> >
> >	32532 @ 30 MHZ version 1.0 optimized ............ 19800
> >	32532 @ 30 MHZ version 1.1 optimized ............ 16600
> >	32532 @ 30 MHZ version 1.1 no global opt ........ 14100
> >
> >	Yes we have a new set of compilers in the works that among
> >	other things supports global optimizations.
> Unfortunately the Dhrystone benchmark does not support global
> optimizations; it says so right in the instructions.  A good
> global optimizer would reduce dhrystone to a few arithmetic
> instructions, 2 calls to times() and 1 to write().  As current
> global optimizers get better they will aproach this ideal by
> eliminating more and more code that does nothing in the benchmark
> but accomplishes real work in the code the benchmark is supposed
> to represent.
> 
> The above numbers represent a dhrystone rating of about 14000, not
> the 18000 previously quoted.
> 
> Of course, the above applies to everyone, I don't mean to single
> out nsc.  If your going to publish a dhrystone number (or any
> benhmark for that matter) keep the global optimizers away from it.
> -- 
> Jim Prescott	rochester!moscom!jgp

While, I agree that using a global optimizing compiler is not exactly
kosher for the dhrystone benchmark it sometimes neccessary.  For 
instance: the GreenHills C compiler is a globally optimizing compiler
which generates good Dhrystone numbers for many architectures including
the 80386 and 68020.	 Unfortunately, I can not find a compiler
switch to turn off the global optimizer.  This leaves me with two choices:
post the numbers with the cavet that this a global optimizing compiler 
or use the results of a medicore compiler like CC.  I don't really
think that global optimization is a problem as long as it is clearly
labeled. 
-- 
Clif Purkiser, Intel, Santa Clara, Ca.
{pur-ee,hplabs,amd,scgvaxd,dual,idi,omsvax}!intelca!clif

These views are my own property.  However anyone who wants them can have 
them for a nominal fee.