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From: Brian Barrett (brbarret_at_[hidden])
Date: 2006-03-09 23:18:01

On Mar 9, 2006, at 6:41 PM, Troy Telford wrote:

> I've got a machine that has the following config:
> Each node has two InfiniBand ports:
> * The first port is on fabric 'a' with switches for 'a'
> * The second port is on fabric 'b' with separate switches for 'b'
> * The two fabrics are not shared ('a' and 'b' can't communicate
> with one
> another)
> I believe that Open MPI is perfectly capable of stripeing over both
> fabric
> 'a' and 'b', and IIRC, this is the default behavior.
> Does Open MPI handle the case where Open MPI puts all of its
> traffic on
> the first IB port (ie. fabric 'a'), and leaves the second IB port (ie.
> fabric 'b') free for other uses (I'll use NFS as a humorous example).
> If so, is there any magic required to configure it thusly?

With mvapi, we don't have the functionality in place for the user to
specify which HCA port is used. The user can say that at most N HCA
ports should be used through the btl_mvapi_max_btls MCA parameter.
So in your case, if you ran Open MPI with:

   mpirun -mca btl_mvapi_max_btls 1 -np X ./foobar

Only the first active port would be used for mvapi communication.
I'm not sure if this is enough for your needs or not.

Hope this helps,


   Brian Barrett
   Open MPI developer