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Subject: Re: [hwloc-users] Thread binding problem
From: Brice Goglin (Brice.Goglin_at_[hidden])
Date: 2012-09-05 09:06:42


Hello Gabriele,

The only limit that I would think of is the available physical memory on
each NUMA node (numactl -H will tell you how much of each NUMA node
memory is still available).
malloc usually only fails (it returns NULL?) when there no *virtual*
memory anymore, that's different. If you don't allocate tons of
terabytes of virtual memory, this shouldn't happen easily.

Brice

Le 05/09/2012 14:27, Gabriele Fatigati a écrit :
> Dear Hwloc users and developers,
>
>
> I'm using hwloc 1.4.1 on a multithreaded program in a Linux platform,
> where each thread bind many non contiguos pieces of a big matrix using
> in a very intensive way hwloc_set_area_membind_nodeset function:
>
> hwloc_set_area_membind_nodeset(topology, punt+offset, len, nodeset,
> HWLOC_MEMBIND_BIND, HWLOC_MEMBIND_THREAD | HWLOC_MEMBIND_MIGRATE);
>
> Binding seems works well, since the returned code from function is 0
> for every calls.
>
> The problems is that after binding, a simple little new malloc fails,
> without any apparent reason.
>
> Disabling memory binding, the allocations works well. Is there any
> knows problem if hwloc_set_area_membind_nodeset is used intensively?
>
> Is there some operating system limit for memory pages binding?
>
> Thanks in advance.
>
> --
> Ing. Gabriele Fatigati
>
> HPC specialist
>
> SuperComputing Applications and Innovation Department
>
> Via Magnanelli 6/3, Casalecchio di Reno (BO) Italy
>
> www.cineca.it <http://www.cineca.it> Tel: +39 051
> 6171722
>
> g.fatigati [AT] cineca.it <http://cineca.it>
>
>
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