Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!pyramid!prls!mips!mark
From: mark@mips.COM (Mark G. Johnson)
Newsgroups: comp.arch
Subject: Longer quote, RPM-40 performance
Message-ID: <1669@mips.mips.COM>
Date: 24 Feb 88 17:22:07 GMT
Lines: 40
Keywords: DAIS, 14 MIPS, General Electric


 
To perhaps clarify what the ISSCC speaker claimed for
performance on the GE "RPM-40" integer unit, here is a
more extensive quotation of his presentation:
.........................................................................
	"We have demonstrated a wire-wrap board with this in, running
	 at 40 MHz, and we have a peak rate of 40 MIPS, of CPU
	 instructions."

	"Somebody's going to ask, `What's that in real MIPS ?'  We have
	 done a comparison between this instruction set and this
	 architecture on the 1750A DAIS MIPS (which is a standard Air
	 Force mix of instructions) and our most pessimistic value on
	 that is 14 MIPS."

	"We compare that with the best machines around and we're talking
	 about at least a two or three to one speedup when using this
	 technique --- although it's not a 1750, don't run away with
	 that idea."
.........................................................................
Now, what was meant by _the_best_machines_around_ ?? Possibilities
include:
	1.  The other CORE-MIPS contractors (Unisys, McDonnell, TI)
	2.  Mil-spec 1750A machines running the DAIS mix
	3.  Mil-spec 68020's or 80286's with no wait states
	4.  Top end VAX (8800?) emulating the DAIS mix
	5.  IBM and Amdahl machines emulating the DAIS mix
	6.  Cyber-190 or Cray-2 on integer code

To me, (2.) seems most likely, as this would imply a performance of
4.7 - 7 MIPS for existing mil-spec 1750A processors (on the DAIS mix).
It would also be the sort of military-embedded-computer vs.
military-embedded-computer comparison that would be most interesting
to the RPM-40's potential customers.  Machines 4-6, which arguably
include some of "the best machines around" for running operating systems
and/or integer programs, aren't optimized to fit in the nosecone of a
missile, fly through clouds of radiation, and run an Ada program
to "track the BadGuy, collide with him, & go Bang".

-- MJ