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Subject: Re: [hwloc-users] Process and thread binding
From: Brice Goglin (Brice.Goglin_at_[hidden])
Date: 2011-09-12 08:12:23


Le 12/09/2011 13:58, Gabriele Fatigati a écrit :
> Hi Brice,
>
> but in the manual is not written that get_cpubind() returns the
> logical OR of the binding of all threads... I ever understand that
> returns the bind of the calloer, where the caller can be process or
> thread..

A process is a container that contains one or several threads. The
binding is where something can run. It's normal that "where a process
can run" is "where any of its threads can run", which means it's the
logical OR of their binding.

>
> I'm mixing bind of process and threads, and I've noted that if the
> process and thread are on the same NUMA node, works well, also on
> different cores.
>
> If the NUMA node of process is different of NUMA node of threads,
> there is a problem.
>

Well, the first thing to understand is what you're trying to do here. In
the vast majority of cases, binding a thread outside of the binding of
the corresponding process looks like buggy programming.

Brice