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Subject: Re: [hwloc-users] Numa availability
From: Brice Goglin (Brice.Goglin_at_[hidden])
Date: 2011-08-28 06:35:43


Le 28/08/2011 12:14, Gabriele Fatigati a écrit :
> Dear hwloc users,
>
> what happens if I use hwloc on a non-NUMA machine? I suppose memory
> binding has no sense because there is not a memory locality concept.
> And regards execution binding? are there some difference on a non-NUMA
> machine?

Hello Gabriele,

Execution binding remains exactly the same.

Memory binding has no sense on non-NUMA machine but it's still available
for application portability (it basically just does nothing).

> Is there a hwloc routine to check this?

get_nbobjs_by_type(topology, HWLOC_OBJ_NODE) tells how many NUMA node
objects exist.
If you get >1, the machine is NUMA.
If the non-NUMA case, I think you can get 0 or 1 depending on whether
the OS is NUMA-aware or not (not sure we should remove this possible
difference).

Brice