Messages in this thread | | | Date | Fri, 03 Apr 2009 22:16:03 +0200 | From | Brice Goglin <> | Subject | Re: Off topic: Numactl "distance" wrong |
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Chris Worley wrote: > Sorry for an off topic, but I'm hoping somebody can point me in the > right direction of where to direct this question... > > I have an Opteron system where I've seen the HW diagrams, and each of > 4 sockets is directly connected (HT) to two other sockets, and two HT > hops away from a third (i.e. a simple square topology, no X in the > middle). > > Yet, "numactl --hardware" shows but one hop to each socket: > > # numactl --hardware > ... > node 0 1 2 3 > 0: 10 20 20 20 > 1: 20 10 20 20 > 2: 20 20 10 20 > 3: 20 20 20 10 > > I know this is wrong. > > Who would be the right person (or list) to talk about this? >
IIRC, the motherboard/BIOS is supposed to report numa distances through the PXM ACPI method. But I have never seen any opteron box do it properly. So you just get 10 for "local" and 20 for "remote". Some Itanium machines however report actual distances.
Brice
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