Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!stat!mccalpin From: mccalpin@stat.fsu.edu (John Mccalpin) Newsgroups: comp.arch Subject: Re: The Killer Micro From Hell Summary: more Cray vs MIPS blathering.... Keywords: price/performance ratios, benchmarking Message-ID: <789@stat.fsu.edu> Date: 30 Dec 89 21:51:53 GMT References: <158@csinc.UUCP> <787@stat.fsu.edu> <42701@lll-winken.LLNL.GOV> <788@stat.fsu.edu> <42737@lll-winken.LLNL.GOV> Reply-To: mccalpin@stat.fsu.edu (John Mccalpin) Organization: Supercomputer Computations Research Institute Lines: 59 In article <788@stat.fsu.edu> I wrote: >So applying some scaling suggests that a 4-cpu Cray Y/MP at 6 ns will >be about 290 times as fast as the R-3000 box. Then scale the MIPS cpu.... To which brooks@maddog.llnl.gov (Eugene Brooks) replied: >So to really compare one processor to one processor, as any reasonable person ^^^^^^^^^^^^^^^^^^^^^^^^ >would do, we divide the 290 by 4 to get a ratio of 72 for the 6 NS Y to the ^^^^^^^^ >R3000. [...details deleted...] you get a factor of 29 for the YMP vs the R6000. So, I am not a reasonable person? I compared a configuration of the Cray which is _smaller_ than the one I ran on with the only configuration of the MIPS product that I have even heard of. The MIPS is not even announced yet as a single-processor, so it is giving a slight advantage to the killer micro, since it is comparing a delivered system to an unannounced one.... Maybe I should use single-cpu performance comparisons with my Connection Machine results? :-) >The bottom line, roughly 30 times the speed for 30 times >the cost for code which is fully vectorized on the Y. There is an absolute >performance advantage but no cost-performance advantage. If the MIPS box had enough memory and disk to run the same jobs that I run on the Cray, then the Cray should be about 2 times more cost-effective in that naive measure. Of course if I have a job that takes 100 hours on an 8-processor Y/MP, then I would have to wait for 59 weeks on the (almost) equally cost-effective "KILLER MICRO from HELL". >If your code is not 99% vectorized, however, you are very foolish to run >it on a traditional supercomputer cpu. As you correctly point out. Well, I didn't say "very foolish", but as a taxpayer I would prefer people to use the more expensive of the government-owned machines only for jobs that they are reasonably cost-effective for.... I wrote: >This is all just as excuse to remind Eugene :-) that some users will >still be able to make effective use of vector supercomputers. In Eugene replied: >I pointed out in my posting that Killer Micros have overrun traditional >supercomputers in scalar performance. I qualified this very explicitly >in my posting. The notion that I need to be reminded that traditional >supercomputers are still hanging in there for codes which are nearly 100% >vectorized is silly. >brooks@maddog.llnl.gov, brooks@maddog.uucp That's what the smiley face was there for.... By the way, the most cost-effective machine on my code is the new Stardent 3000. It runs at about 1/15 of the speed of the Cray on a per-cpu basis and is less than 1/50 of the cost.... Too bad I can't afford one!