On 29-set-09, at 18:55, Fawzi Mohamed wrote:

ok, I was thinking that maybe you did/would like to provide in the
future something akin to what opensolaris does with locality groups
http://opensolaris.org/os/community/performance/mpo_overview.pdf

Yes, we intend to provide something similar.

In fact what I "need" (or at least I think I need ;) is just the next
neighbors, basically I go up the hierarchy, and look which new
neighbors I have, so some hierarchy like the lgroups is close to what
I need, and simpler to handle than the full graph.

That's what future heuristics would build for you, yes.

tha's great, I am really looking forward to it.

So as summary, if I have understood correctly the current idea for the (future) structure of hwloc is:

1) a fully hierarchical representation of the machine/hardware where each level is a partition, and each level fully covers the previous one (from any node you go through all levels using father/childrens, father/child are just one level away from each other.
This is basically what is there now.

2) outside the hierarchy 1 (but built using its object, probably the NUMA nodes) there will be
2.1) maybe the full connection graph
2.2) a hierarchical view of it, like the lgroups, where the levels are not necessarily a partition, and that could also refer not to the sublevel, but directly to lower levels. Going up the hierarchy you get the next neighbors.

Separating 1 & 2 has the advantage that stronger assumption can be done on 1, simplifying it.

ciao
Fawzi