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Subject: Re: [OMPI devel] btl/openib: get_ib_dev_distance doesn't see processes as bound if the job has been launched by srun
From: Brice Goglin (Brice.Goglin_at_[hidden])
Date: 2012-02-09 08:06:53


Jeff Squyres <jsquyres_at_[hidden]> a écrit :

>On Feb 9, 2012, at 7:50 AM, Chris Samuel wrote:
>
>>> Just so that I understand this better -- if a process is bound in a
>>> cpuset, will tools like hwloc's lstopo only show the Linux
>>> processors *in that cpuset*? I.e., does it not have any
>>> visibility of the processors outside of its cpuset?
>>
>> I believe that was the intention - there's no real benefit to knowing
>
>> about resources that you can't access or use (and will likely get an
>> error if you do) to my mind.
>
>The real question, however, is how are IO devices represented if you
>don't do WHOLE_SUBSYSTEM? I.e., what about IO devices that are not
>local to the socket of your cpuset, for example?
>
>Take this sample image, for example:
>
> http://www.open-mpi.org/projects/hwloc/devel09-pci.png
>
>What if my cpuset is only on Socket P#0? What exactly will be reported
>via (WHOLE_SUBSYSTEM | HWLOC_TOPOLOGY_FLAG_WHOLE_IO)?

I actually fixed something related to this case in 1.3.2. The device will be attached to the root object in this case iirc.

Brice