Many thanks for looking into this and filing a bug report at 11:16PM!
Thanks to Aurelien, Ralph and Nathan for their help and clarifications
Add a note to the FAQ explaining that in OMPI 1.8
the new (default) btl is vader (and what it is).
It was a real surprise to me.
If Aurelien Bouteiller didn't tell me about vader,
I might have never realized it even existed.
That could be part of one of the already existent FAQs
explaining how to select the btl.
Doubts (btl in OMPI 1.8):
I still don't understand clearly the meaning and scope of vader
being a "default btl".
Which is the scope of this default: intra-node btl only perhaps?
Was there a default btl before vader, and which?
Is vader the intra-node default only (i.e. replaces sm by default),
or does it somehow extend beyond node boundaries, and replaces (or
brings in) network btls (openib,tcp,etc) ?
If I am running on several nodes, and want to use openib, not tcp,
and, say, use vader, what is the right syntax?
* nothing (OMPI will figure it out ... but what if you have
* -mca btl openib (and vader will come along automatically)
* -mca btl openib,self (and vader will come along automatically)
* -mca btl openib,self,vader (because vader is default only for 1-node jobs)
* something else (or several alternatives)
Whatever happened to the "self" btl in this new context?
Gone? Still there?
On 10/16/2014 11:16 PM, Jeff Squyres (jsquyres) wrote:
On Oct 16, 2014, at 1:35 PM, Gus Correa <g...@ldeo.columbia.edu> wrote:
and on the MCA parameter file:
btl_sm_use_knem = 1
I think the logic enforcing this MCA param got broken when we revamped the MCA
param system. :-(
I am scratching my head to understand why a parameter with such a
suggestive name ("btl_sm_have_knem_support"),
so similar to the OMPI_BTL_SM_HAVE_KNEM cpp macro,
somehow vanished from ompi_info in OMPI 1.8.3.
It looks like this MCA param was also dropped when we revamped the MCA system.
There's some deep mojo going on that is somehow causing knem to not be used;
I'm too tired to understand the logic right now. I just opened
https://github.com/open-mpi/ompi/issues/239 to track this issue -- feel free to
subscribe to the issue to get updates.