Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!uakari.primate.wisc.edu!xanth!lll-winken!vette!brooks From: brooks@vette.llnl.gov (Eugene Brooks) Newsgroups: comp.arch Subject: Re: ATTACK OF KILLER MICROS Message-ID: <35979@lll-winken.LLNL.GOV> Date: 17 Oct 89 01:10:58 GMT References: <35825@lll-winken.LLNL.GOV> <1081@m3.mfci.UUCP> <35896@lll-winken.LLNL.GOV> Sender: usenet@lll-winken.LLNL.GOV Reply-To: brooks@maddog.llnl.gov (Eugene Brooks) Organization: Lawrence Livermore National Laboratory Lines: 30 In article mccalpin@masig3.ocean.fsu.edu (John D. McCalpin) writes: >The larger chip vendors are paying more attention to parallelism now, >but it appears to be in the context of 2-4 processor parallelism. It >is not likely to be possible to make these chips work together in >configurations of 1000's with the application of "glue" chips.... These microprocessors, for the most part, are being designed to work in a small processor count coherent cache shared memory environment. This is the reason why examining scalable coherent cache systems is so imporant. The same micros, with their capability to lock a cache line for a while to do an indivisible op, will work fine in the scalable systems. I agree that they won't be optimal, but they will be within 90% of optimal and that is all that is required. The MAJOR problem with current micros in a scalable shared memory environment is their 32 bit addressing. Unfortunately, no 4 processor system will ever need more than 32 bit addresses, so we will have to BEG the micro vendors to put in bigger pointer support.. >This is not to mention the fact that software technology for these >parallel supercomputers is depressingly immature. I think traditional >moderately parallel machines (e.g. Cray Y/MP-8) will be able to handle >existing scientific workloads better than 1000-processor parallel >machines for quite some time.... The software question is the really hary one, that is why LLNL is sponsoring the Massively Parallel Computing Initiative. We see scalable machines being very cost effective and are making a substantial effort in the application software area. brooks@maddog.llnl.gov, brooks@maddog.uucp