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From: vac@crux.fac.cs.cmu.edu (Vincent Cate)
Newsgroups: comp.arch
Subject: Re: $/CPUmark is a worthless measure
Message-ID: <1991Apr3.074148.11109@cs.cmu.edu>
Date: 3 Apr 91 07:41:48 GMT
Sender: netnews@cs.cmu.edu (USENET News Group Software)
Organization: School of Computer Science, Carnegie Mellon
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>$/SPECmark, or $/any-CPU-benchmark, is about as useful 
>[...]
>They're no better than order-of-magnitude, and they stink.
>
>People don't buy CPUs.  They buy systems.  This discussion has focused on
>workstations.  That means disk, memory, keyboard, display, and maybe a
>network card.  (Or does it?  One of the egregious bogus comparisons here
>actually compared $/SPECxyzzy for machines with and without disks!)

SPEC runs on a system not a CPU.  The compiler, system bus, memory 
speed and size, cache speed and size, and the CPU speed all go into 
this number.  Sure, its not an I/O benchmark, but you should talk to 
some i860 people or something if you still think SPEC is a CPU benchmark.  

Now SPEC/MHZ, that is a ridiculous number.  Does someone think that
all CPUs have the same number of gate-delays between pipeline stages?  
MHZ is like MIPS, it just does not compare across architectures.
Normalizing based on cost is the best that we can really do.
$/SPECmark is a number I very much like seeing even though it does 
not include things like how many bus slots, screen size, or the number 
of function keys on the keyboard.  I hope we see $/SPEC again in the
future.

    -- Vince