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Subject: Re: [hwloc-devel] [hwloc] #12: support user-defined processor restriction
From: Samuel Thibault (samuel.thibault_at_[hidden])
Date: 2010-02-15 17:02:05


Ashley Pittman, le Mon 15 Feb 2010 21:52:29 +0000, a écrit :
> On 15 Feb 2010, at 21:46, Samuel Thibault wrote:
> >> I say the commit r1726 which closed #21 and am working on testing this now, it certainly appears to be what I requested.
> >
> > Maybe, depending on whether you want to discover according to the other
> > process' binding (sched_setaffinity) or according to the other process'
> > restricted view of the machine (Linux cpuset).
>
> I don't understand the difference, I thought they were two ways of achieving the same thing?

Linux cpusets are administrator restrictions. A normal user can not
escape its cpuset. It can however choose the binding within that
cpuset. That is why by default hwloc limits its topology detection
to the cpuset of the current process, since it's not allowed to bind
threads of the process beyond that anyway. (same for the set of online
cpus).

Samuel