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Subject: Re: [OMPI users] Role of ethernet interfaces of startup of openmpi job using IB
From: Prentice Bisbal (prentice_at_[hidden])
Date: 2011-09-27 17:03:23


On 09/27/2011 07:50 AM, Jeff Squyres wrote:
> On Sep 27, 2011, at 6:35 AM, Salvatore Podda wrote:
>
>> We would like to know if the ethernet interfaces play any role in the startup phase of an opempi job using InfiniBand
>> In this case, where we can found some literature on this topic?
>
> Unfortunately, there's not a lot of docs about this other than people asking questions on this list.
>
> IP is used by default during Open MPI startup. Specifically, it is used as our "out of band" communication channel for things like stdin/stdout/stderr redirection, launch command relaying, process control, etc. The OOB channel is also used by default for bootstrapping IB queue pairs.

To clarify, is IP/Ethernet required, or will IPoIB be used if it's
configured on the nodes? Would this make a difference.

Just curious,
Prentice