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From: tim@amdcad.UUCP (Tim Olson)
Newsgroups: comp.arch
Subject: Re: Am29000 and MIPS
Message-ID: <15213@amdcad.UUCP>
Date: Wed, 18-Mar-87 11:36:53 EST
Article-I.D.: amdcad.15213
Posted: Wed Mar 18 11:36:53 1987
Date-Received: Fri, 20-Mar-87 00:51:47 EST
References: <15192@amdcad.UUCP> <1423@husc6.UUCP>
Reply-To: tim@amdcad.UUCP (Tim Olson)
Organization: Advanced Micro Devices, Sunnyvale, California
Lines: 26
Keywords: RISC MIPS

In article <1423@husc6.UUCP> reiter@harvard.UUCP (Ehud Reiter) writes:
>In article <15192@amdcad.UUCP> bcase@amdcad.UUCP (Brian Case) writes:
>>The Am29000 ...  25 MHz clock (40 ns cycle time) ...
>>25 MIPS max., 17 MIPS sustained running big programs
>
>MIPS is of course one of the most unfortunate terms in computer performance.
>It seems to have two meanings:
>   a)  how much faster a manufacturer thinks his machine is compared
>to a VAX-11/780 (usually comparing integer C programs against a 4.2 BSD VAX
>using standard Berkeley cc).
>   b)  the number of million instructions per second that a computer executes.
>
You are correct, the numbers quoted above are Am29000 MIPS.  The 17 MIPS
sustained average translates to around 14 - 15 VEMs (Vax-Equivalent MIPS)
(Gee, maybe we should use that term for b! :-)

"MIPS" is not necessarily a meaninless indicator.  It can provide
information on processor throughput (i.e. how much the processor is
affected by pipeline stalls, jumps, cache and TLB misses...) when
running real programs.  However, it must be combined with the number of
instructions executed to derive the real measure of performance (1/s).

	-- Tim Olson
	Advanced Micro Devices
	Product Planning, Programmable Processors
	(tim@amdcad)