Path: utzoo!utgpu!utstat!jarvis.csri.toronto.edu!mailrus!ames!oliveb!sun!snafu!lm
From: lm@snafu.Sun.COM (Larry McVoy)
Newsgroups: comp.arch
Subject: Re: Don't look back
Message-ID: <91474@sun.uucp>
Date: 28 Feb 89 01:53:00 GMT
References: <13582@winchester.mips.COM> <20667@lll-winken.LLNL.GOV> <7330@pyr.gatech.EDU> <656@m3.mfci.UUCP> <20821@lll-winken.LLNL.GOV> <661@m3.mfci.UUCP> <20862@lll-winken.LLNL.GOV> <675@m3.mfci.UUCP>
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Reply-To: lm@sun.UUCP (Larry McVoy)
Organization: Sun Microsystems, Mountain View
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In article <675@m3.mfci.UUCP> rodman@mfci.UUCP (Paul Rodman) writes:
$ I'm sure you've read Olaf Ludbeck paper
$ from Los Alamos, haven't you? What does that paper tell *you*? It tells
$ me that even if the vector machines at Los Alamos had *infinite* speed 
$ vector units the speedups are dismal. In a *decade*+ of programming vector
$ machines, some of the best scientists in the world haven't improved the
$ percent vectorization. 


I really don't have a lot to add to this other than to repeat it.  It
seems that a lot of people out there think VECTOR is the word of God.  I
remember this paper and I remember various discussions over coffee when I
worked at ETA.  The conclusion was then and is now "if you can't scream on
non-vectorizable, integer code, forget it" (ETA can forget it).  You want
a fast Unix box?  Get an Amdahl - 30 MIPS and the I/O to go with it.  You
want to build your own?  Concentrate on I/O and integer performance.
That's your bread and butter.

Larry McVoy, Lachman Associates.			...!sun!lm or lm@sun.com