On Wed, 2011-05-25 at 19:06 -0400, Jeff Squyres wrote:
> I'm not sure what you're saying here. There is a large difference
> between "--mca a,b,c" and "--mca a,b".
> In the former, all 3 communication methods will be used (a, b, and c).
> In the latter, only 2 will be used (a and b).
> To be clear, if you explicitly list which BTLs to use, OMPI will only
> (try to) use exactly those and no others.
It might be worth putting the sm btl in the FAQ: