On Mar 19, 2016, at 11:53 AM, dpchoudh . <dpcho...@gmail.com> wrote: > > 1. Why 'self' needs to be explicitly mentioned when using the BTL > communication? Since it must always be there for MPI communication to work, > should it not be implicit? I am sure there is some architectural rationale > behind this; could someone please elaborate?
The original intent: it's actually meant to be a BTL, just like any other. In that sense, if you list an "include" list of BTLs, it needs to be listed -- just like any other. That being said, you're right -- it *is* a little silly these days to have to explicitly list "self" because no other component has ever replaced it for process-loopback communication. It might not be too hard to update mca_btl_base_select() to automatically add "self" to the "include" list, if it wasn't explicitly mentioned...? Want to submit a PR? :-) > 2. Why is this (using 'self') not needed when using MTL communication? BTLs and MTLs are exclusive. Specifically, see https://github.com/open-mpi/ompi/blob/master/README#L590-L628. > 3. Is it possible to mix BTL and MTL on a single OMPI job? By design, no. The cm PML was designed to select exactly one MTL for use, as opposed to the ob1 PML, which was designed to select multiple BTLs for use. > For example, if I have a card, let's say Texas Instruments Hyperlink, that is > only available as BTL, and I also have Qlogic cards on the same nodes, can I > use something like this: > > mpirun -np 3 -H h1,h2,h3 -mca MTL psm -mca BTL self,hlink > > 4. If the above answer is yes, then would OpenMPI use both cards > *simultaneously* (and stripe messages) or would it use the one with higher > exclusivity and put the other as standby for failure recovery? > > Thanks in advance > Durga > > Life is complex. It has real and imaginary parts. > _______________________________________________ > users mailing list > us...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users > Link to this post: > http://www.open-mpi.org/community/lists/users/2016/03/28758.php -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
