Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!mash From: mash@mips.com (John Mashey) Newsgroups: comp.arch Subject: Re: Data General NEW AVIION machine Keywords: Data General, Avvion, 88000, 88K, MIPS, Motorola, UNIX Message-ID: <1118@spim.mips.COM> Date: 19 Mar 91 02:01:35 GMT References: <1991Mar14.134319.22796@news.larc.nasa.gov> <1991Mar16.073539.823@berlioz.nsc.com> <4183@bnr-rsc.UUCP> Sender: news@mips.COM Organization: MIPS Computer Systems, Inc. Lines: 50 Nntp-Posting-Host: winchester.mips.com In article <4183@bnr-rsc.UUCP> tak@bnr-rsc.UUCP (Mike Takefman) writes: >In article <1991Mar16.073539.823@berlioz.nsc.com> my@tern.nsc.com (Michael Yip) writes: >| >|> MIPS ratings of multiprocessor machines aren't necessarily meaningful. >|> If I have one task I want to run, that 115 MIPS machine is only one-fourth >|> that speed. (It is a four-processor system.) >| ........deleted......... >|How fast is each processor anyway? Let's see ... 115/4 = 31 MIPS ... >|so the processor is 40MHz? (Is 88K a super-scaler? Not yet, right?) > >I have a DG AViiON-100 on my desk. Even though it is a 16.67 MHz 88k, DG >insists on calling the box a 17 Mips machine. Xcalc gives me 115/4=28.75 >so I'm guessing that the marketing types are being a little more honest >and refering to a 33 MHz 88k as a 28.75 MIP processor, (unless they >are calling a 25MHz 88k a 29 MIP processor :-). Otherwise I have no info >on this machine. EETimes says it's 4 CPUs at 25MHz. It also says that it uses 8 of the new 88204 CMMUs (which have 64KB each). I must admit surprise about the 88204: I hadn't thought it was out yet. It is, of course, rather desirable for the performance ofthis system, in that if you do the simulations, you find that 4 88100s & 8 88200s may often not give you much more performance than 2 88100s & 8 88200s, because the shared bus ends up getting thrashed by the insufficiently high hit rate from the 16KB 88200s. (This is for system running jobs that include OS time, i.e., substantive shared data.) The 4X bigger 88204s seem, on the surface, necessary to make a sensible 4-way 88K system, using the standard parts in standard arrangements. (I think this is why most of the 88K MP systems on the market have ended up being 2-way, i.e., 2 88100s + 4-8 88200s.) I note that the fastest DG AVIION for which SPEC numbers have been published, to my knowledge, is the 6200, yielding 15.3 on SPECinteger. The EETimes article had other interesting quotes, such as: "Motorola claimed that it has seven versions of the 88000 in design and will produce 300-Mips parts before 1995 with superscalar implementations." Does anybody know, for sure: a) Does DG, right now, have 88204s in there? b) Is there ANY performance data? [The 117-mips number is NOT data.] c) What does the memory system look like on this? -- -john mashey DISCLAIMER: UUCP: mash@mips.com OR {ames,decwrl,prls,pyramid}!mips!mash DDD: 408-524-7015, 524-8253 or (main number) 408-720-1700 USPS: MIPS Computer Systems MS 1/05, 930 E. Arques, Sunnyvale, CA 94086