My understanding is far below `imperfect'! However, our box has all 8 slots filled with 2GB PC2100s... Not a whole lot of room for change.
Best, Andy > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > > 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] > 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 ------------------------------------------------------------------------------ Notice: This e-mail message, together with any attachments,...{{dropped}} ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-devel
