Re: Off topic: Numactl "distance" wrong

From: David Rientjes
Date: Fri Apr 03 2009 - 17:43:57 EST


On Fri, 3 Apr 2009, Andi Kleen wrote:

> > Who would be the right person (or list) to talk about this?
>
> Your BIOS vendor whose code reported the wrong values. Not that it matters
> really on small systems.
>

The numactl --hardware values are coming directly from the sysfs per-node
distance interface, so this may not be a result of erroneous BIOS data but
rather the lack of a SLIT to describe the physical topology better. When
we lack a SLIT, nodes are simply given these remote distances of 20
because their ids differ.

Yinghai, can you elaborate on exactly what type of interface you can
imagine for modifying the distance for nodes through sysfs? It seems like
you'd have to report the entire physical topology in one write, for which
we currently don't have an interface for beyond pxms, instead of per-node
distances to remote nodes.
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