Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!snorkelwacker!apple!sun-barr!lll-winken!maddog!brooks From: brooks@maddog.llnl.gov (Eugene Brooks) Newsgroups: comp.arch Subject: Re: Coherent cache for Killer Micros Message-ID: <40110@lll-winken.LLNL.GOV> Date: 1 Dec 89 07:10:44 GMT References: <13910002@hpisod2.HP.COM> Sender: usenet@lll-winken.LLNL.GOV Reply-To: brooks@maddog.llnl.gov (Eugene Brooks) Organization: Lawrence Livermore National Laboratory Lines: 14 In article <13910002@hpisod2.HP.COM> dhepner@hpisod2.HP.COM (Dan Hepner) writes: >Is a coherent cache system essential or just nice? And why? It is essential if your cost of computing is dominated by software development costs. A system with large coherent caches allows you to exploit data locality by suitably mapping processors to the data set, but still allows the maintenance of a shared memory programming environment. At our laboratory, the cost of coding dominates the cost of computing by about a factor of 5. Coding cost is a very high priority issue because of this. The situtation may be different in other environments, ours may be unique with respect to the complexity of physical simulation codes and the daily modifications to them that occurs to support new physics as the designers who use the codes run their problems. brooks@maddog.llnl.gov, brooks@maddog.uucp Brought to you by Super Global Mega Corp .com