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From: brooks@vette.llnl.gov (Eugene Brooks)
Newsgroups: comp.arch
Subject: Re: ATTACK OF KILLER MICROS
Message-ID: <36232@lll-winken.LLNL.GOV>
Date: 19 Oct 89 19:32:45 GMT
References: <35825@lll-winken.LLNL.GOV> <2121@brazos.Rice.edu> <35897@lll-winken.LLNL.GOV> <9078@batcomputer.tn.cornell.edu>
Sender: usenet@lll-winken.LLNL.GOV
Reply-To: brooks@maddog.llnl.gov (Eugene Brooks)
Organization: Lawrence Livermore National Laboratory
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In article <9078@batcomputer.tn.cornell.edu> kahn@tcgould.tn.cornell.edu writes:
>The Cray-XMP is considerably slower than the YMP.  
The YMP is 30% faster than a the XMP I was referring to.  This is
for scalar dominiated compiled code and is a rather general result.
Just in case you doubt my sources, I runs codes on both a YMP 8/32
and an XMP 4/16 frequently enough to be a good judge of speed.

>The single-processor XMP is no-longer a supercomputer.
Only if the difference between supercomputer and not is a 30% speed increase.
I argue that a 30% speed increase is not significant, a frigging factor of
2 is not significant from my point of view.  Both the XMP and the YMP
are in the same class.  Perhaps later YMPs will have more memory putting
them in a slightly improved class.

>Take a program requiring more than 128MBytes of memory (or 64 MBytes
>for that matter (but I personally prefer more than 256M to excerice the
>VM system alittle!)) (i.e. a relatively BIG job, a *supercomputer* job)
>and then compare any micro you want 
>or any other system you want with the YMP. or something in
>that class.  and then try it on a multiprocessor YMP,  and Please 
>STOP USING A SINGLE-PROCESSOR xmp AS THE DEFINITION OF A SUPERCOMPUTER, 
>thank you.
I have no interest in single cpu micros with less than 128MB.
I prefer 256 MB.  I want enough main memory to hold my problems.


>And it would be nice if people used "LIST PRICE" for "COMPLETE SYSTEMS"
>when comparing prices.  (LIST PRICE = PEAK PRICE !!) (COMPLETE SYSTEM =
>with all needed software and a few GBytes of disk with a few controllers)
I am talking list price for the system.  A frigging XMP eating micro with
suitable memory, about 64 meg at the minimum, can be had for 60K.  The
YMP costs about 3 million a node.  The micro matches its performance for
my applications.  Which do you think I want to buy time on?  Of course,
I prefer a 3 million dollar parallel micro based system which has 50-100
nodes and runs circles around the YMP processor for my application.


brooks@maddog.llnl.gov, brooks@maddog.uucp