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Subject: Re: [hwloc-users] Numa availability
From: Gabriele Fatigati (g.fatigati_at_[hidden])
Date: 2011-08-28 08:47:30


Mm,

in each case, if get_nbobjs_by_type return 0, also if the machine is NUMA,
hwloc can't build the NUMA-aware topolog, so the NUMA capability is not
usable. Is it right?

2011/8/28 Samuel Thibault <samuel.thibault_at_[hidden]>

> Brice Goglin, le Sun 28 Aug 2011 12:36:31 +0200, a écrit :
> > > 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).
>
> The useful difference is that 0 means we don't know, while 1 means we do
> know there is only one node.
>
> Samuel
>

-- 
Ing. Gabriele Fatigati
HPC specialist
SuperComputing Applications and Innovation Department
Via Magnanelli 6/3, Casalecchio di Reno (BO) Italy
www.cineca.it                    Tel:   +39 051 6171722
g.fatigati [AT] cineca.it