[ofa-general] OFED-1.1, mvapich and openmpi question

[Jeff Squyres]

On Mar 9, 2007, at 10:44 AM, Jeff Squyres wrote:

>> 1. For openmpi we have used the "--mca btl openib,self
>> ..." as command line option and it is
>> running fine, now the question is how to make sure
>> the it uses IB for mpi communication??
>
> This parameter tells Open MPI to only use the "openib" and "self"  
> plugins for MPI communications.

I neglected to mention that by default, Open MPI should use as many  
networks as it can.  So if it finds an OFED-based network adapter,  
it'll use it (and implicitly disable tcp).  Hence, you shouldn't need  
to specify the "--mca btl [sm,]openib,self" parameter.  There is no  
harm in doing so, of course -- it's just unnecessary.

More specifically, if you have the "openib" BTL plugin properly  
installed (e.g., via the OFED installer), it will complain if it is  
available and *not* used (e.g., no OFED-based network adapters were  
found / available to be used).

Hope that helps.

-- 
Jeff Squyres
Cisco Systems