Open MPI logo

Open MPI Development Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Development mailing list

Subject: [OMPI devel] sm BTL "extra procs"
From: Eugene Loh (Eugene.Loh_at_[hidden])
Date: 2008-12-22 11:47:16


Why does the sm BTL allocate "extra procs"?

E.g.,

https://svn.open-mpi.org/trac/ompi/browser/branches/v1.3/ompi/mca/btl/sm/btl_sm.c?version=19785#L403

In particular:

*) sm_max_procs is -1 (so there is no max)
*) sm_sm_extra_procs (sic, this is the ompi_info name) is 2

So, if there are n procs on the node, it allocates FIFOs for n*(n+2)
connections. Why?