And my understanding is completely imperfect, but note that organization (and selection) of memory modules on the motherboard can be critical for speed with the opterons; well known issue on the beowulf lists.
best, -tony Peter Dalgaard <[EMAIL PROTECTED]> writes: > "Liaw, Andy" <[EMAIL PROTECTED]> writes: > >> Hi Martin, >> >> When I attended the LinuxWorld Expo in NYC back in January, I chatted with >> some folks at the AMD booth, as well as guys from Penguin Computing (where >> we bought our Opteron box). I was told that the Operton has this somewhat >> strange setup that the memory is controlled by one CPU. The net effect of >> this being that when both CPUs are running, one might only be running at >> around 90% instead of 99%. The `NUMA' kernel is supposed to fix this >> problem. I wonder if this is related to the performance of the threaded >> GOTO lib that you saw. Has anyone tried the NUMA kernel? >> >> Best, >> Andy > > My understanding is slightly different (I could be wrong though, I'm > hardly a hardware engineer): Each CPU controls one block of memory, > and only some motherboard have memory slots for both CPUs. If CPU2 > wants to talk to CPU1's memory it has to ask CPU1 for it, with the > obvious potential for a performance hit. > > I'll see if I can get around to redoing my Opteron builds and trying > Martin's benchmarks in the next couple of days. > > -p > > -- > O__ ---- Peter Dalgaard Blegdamsvej 3 > c/ /'_ --- Dept. of Biostatistics 2200 Cph. N > (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 > ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-devel > -- [EMAIL PROTECTED] http://www.analytics.washington.edu/ Biomedical and Health Informatics University of Washington Biostatistics, SCHARP/HVTN Fred Hutchinson Cancer Research Center UW (Tu/Th/F): 206-616-7630 FAX=206-543-3461 | Voicemail is unreliable FHCRC (M/W): 206-667-7025 FAX=206-667-4812 | use Email CONFIDENTIALITY NOTICE: This e-mail message and any attachme...{{dropped}} ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-devel
