Path: utzoo!attcan!uunet!husc6!mailrus!ames!amdahl!pyramid!prls!mips!mash From: mash@mips.COM (John Mashey) Newsgroups: comp.arch Subject: Re: The VAX Always Uses Fewer Instructions Keywords: VAX MIPS Message-ID: <2476@winchester.mips.COM> Date: 30 Jun 88 08:11:04 GMT References: <6921@cit-vax.Caltech.Edu> <28200161@urbsdc> <10595@sol.ARPA> <914@entropy.ms.washington.edu> <12179@mimsy.UUCP> Reply-To: mash@winchester.UUCP (John Mashey) Organization: MIPS Computer Systems, Sunnyvale, CA Lines: 29 In article <12179@mimsy.UUCP> chris@mimsy.UUCP (Chris Torek) writes: ... >Who cares about the arguments? The fact is that if you have somewhere >between $10,000 and $1,000,000, and want to buy the fastest machine you >can get for that, right now that machine is probably `RISC-based'. > >You can argue all you like as to why the Vax instruction set is better, >or why the 88000 instruction set is better, but the fastest Vax CPU from >DEC is slower than the fastest 88000 CPU from Motorola. --------^^^^^^ On what set of benchmarks is this assertion based? (I believe it's true for integer and single-precision FP, and if you'd said MIPS, it would have been true for DP floating also :-) So far, the only double-precision floating-point number we've seen for the 88K is Whetstone: 3 Megawhets (and I don't remember the source, sorry). (An 8700 is about 4Mwhets DP). We'd be VERY interested to see more DP benchmarks: from an examination of the 88K's architecture and the cycle counts, we have reasons to believe that the 88K design essentially SACRIFIED double precision floating performance for most compiled programs. We'd be glad to be disabused by knowledgable folks who can cite useful benchmarks like: DP Livermore Loops, Spice, Doduc, etc. Note one more time that VAX-relative performance numbers, computed the way DEC does, includes floating point..... -- -john mashey DISCLAIMER:UUCP: {ames,decwrl,prls,pyramid}!mips!mash OR mash@mips.com DDD: 408-991-0253 or 408-720-1700, x253 USPS: MIPS Computer Systems, 930 E. Arques, Sunnyvale, CA 94086