Author: Jay Urbanski
Date: 19:19:35 08/30/03
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On August 29, 2003 at 23:41:32, Jeremiah Penery wrote: >On August 29, 2003 at 18:40:23, Mridul Muralidharan wrote: > >>I'm not sure of what/why Prof. Bob Hyatt may have made those comments. But to >>get a program like crafty to work properly in a numa machine will not be trivial >>- and it wont be tweaks , but something more. > >All multi-CPU Opteron machines are NUMA. Crafty will work just fine in those. >It will not be theoretically optimal, but that also depends on the OS to help >with NUMA issues. > >>Duals , etc count as SMP machine not cc-numa which I was refering to. > >Dual Opterons are NUMA. Correct, all Opterons are NUMA. However, they could perhaps be better described as "near SMP". The delta in latencies for remote versus local memory on a two-way is something like ~80ns to ~115ns. Compare this to about ~180 ns for an Intel Xeon shared SMP bus and you're still better off with Opteron even with a standard SMP kernel. If you run an OS with NUMA awareness (Windows 2003 server and some Linux kernels) you'll get even better performance.
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