Messages in this thread | | | From | Erich Focht <> | Subject | Re: Externalize SLIT table | Date | Thu, 4 Nov 2004 16:31:42 +0100 |
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On Thursday 04 November 2004 15:13, Jack Steiner wrote: > I think it would also be useful to have a similar cpu-to-cpu distance > metric: > % cat /sys/devices/system/cpu/cpu0/distance > 10 20 40 60 > > This gives the same information but is cpu-centric rather than > node centric.
I don't see the use of that once you have some way to find the logical CPU to node number mapping. The "node distances" are meant to be proportional to the memory access latency ratios (20 means 2 times larger than local (intra-node) access, which is by definition 10). If the cpu_to_cpu distance is necessary because there is a hierarchy in the memory blocks inside one node, then maybe the definition of a node should be changed...
We currently have (at least in -mm kernels): % ls /sys/devices/system/node/node0/cpu* for finding out which CPUs belong to which nodes. Together with /sys/devices/system/node/node0/distances this should be enough for user space NUMA tools.
Regards, Erich
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