Open MPI logo

Hardware Locality Users' Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Hardware Locality Users mailing list

Subject: Re: [hwloc-users] hwloc set membind function
From: Gabriele Fatigati (g.fatigati_at_[hidden])
Date: 2011-09-22 08:15:26


Hi,

some questions:

1) I don't understand the means of HWLOC_MEMBIND_BIND policy. Why I should
to allocate in a node "near" my cpuset and not in my local node ( where
thread or process runs?)

2) My goal is to replicate the behaviour of set_area_membind_nodeset() in
some manner for all futures allocation without call this function each time
I allocate some memory. Is it possible to do this?

2011/9/22 Brice Goglin <Brice.Goglin_at_[hidden]>

> Le 22/09/2011 12:20, Gabriele Fatigati a écrit :
> > NUMA node(s) near the specified cpuset.
> >
> > What does "nodes near the specified cpuset" means? The node wherethe
> > specified cpuset lives?
> > Set the default memory binding policy of the current process or thread
> > to prefer the
>
> The node near the CPU specified in the cpuset.
>
> > The first thread allocates with a malloc an array. The second thread
> > (bound on other node) initialize the array.
> >
> > The free memory on the nodes decrease only on the node where the
> > second thread is. Is it rigth?
>
> Yes.
>
> >
> > hwloc_set_membind involves all future allocations?
> >
>
> Yes. And already allocated pages if you add the migrate flag.
>
> Brice
>
> _______________________________________________
> hwloc-users mailing list
> hwloc-users_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/hwloc-users
>

-- 
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