Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!wuarchive!udel!nigel.ee.udel.edu!mccalpin From: mccalpin@pereland.cms.udel.edu (John D. McCalpin) Newsgroups: comp.arch Subject: Re: LINPACK 1000x1000 MFLOPS per $$$ Message-ID: Date: 19 Jul 90 15:05:19 GMT References: <5180@ethz.UUCP> Sender: usenet@ee.udel.EDU Organization: College of Marine Studies, U. Del. Lines: 53 In-reply-to: bloepfe@ethz.UUCP's message of 19 Jul 90 09:49:07 GMT In article <> mccalpin@perelandra.cms.udel.edu I wrote about >[using] the measure of LINPACK 1000x1000 MFLOPS per Dollar >to evaluate several computers --- specifically the IBM 3090/180VF, the >Alliant FX/80, the SGI 4D/240, and the Stardent 3040. In article <5180@athz.UUCP> bloepfe@ethz.uucp (Bruno Loepfe) replies: >If you do this kind of calculations, it turns out, that a BYCICLE gives you >the most mph per $$$. How does it come, that nevertheless (almost) everybody >drives a CAR ? This fact makes me think, that some other arguments have to be >considered as well, i.e. it's probably not feasible to watch the "real world" >through a filter "$$$ per " only, where is your >favorite attribute of a computer (or anything else)... >Bruno Loepfe u36@czheth5a.bitnet Apparently I did not make myself clear. I certainly am taking more into account than simple price/performance, as I stated in the previous posting and which has been the main point of my earlier postings on the subject of "Killer Micros". What is novel about this machine is that now: (1) I can get the machine for under $10,000 (2) I can run my *fully vectorizable* application codes at speeds that give me the equivalent of more Cray time than I can reasonably expect to have access to. So on applications for which the Cray is *most efficient*, the IBM machine provides an effective throughput (measured in calculations per calendar month, or some similar units) that exceeds what I can get access to on a Cray. I suspect that most of us also have computer allocations which are equivalent to less than 30 Cray Y/MP hours per month. This in no way diminishes the usefulness of supercomputers. I can still get 1500 MFLOPS performance levels on one of my codes on an 8-cpu Y/MP. What is does shift is the *length* of the jobs for which the faster machine is required. Since I work on projects with annual sorts of time scales, and am willing to run a calculation for 6 months or so, the Cray is only going to be required if I need more than 180 Cray hours in a 6-month period. There are a number of "Grand Challenge" sorts of projects that require that sort of investment in time, but the dividing line of what projects can be done in my office vs what projects must be done at a remote supercomputer site is shifting rapidly toward the largest of projects. -- John D. McCalpin mccalpin@perelandra.cms.udel.edu Assistant Professor mccalpin@vax1.udel.edu College of Marine Studies, U. Del. J.MCCALPIN/OMNET