Dear OpenMPI List:


            I am running the Myrinet MX btl with OpenMPI on MacOSX 10.4.  I am running into a problem.  When I run on one processor per node, OpenMPI runs just fine.   When I run on two processors per node (slots=2), it seems to take forever (something is hanging).


Here is the command:

mpirun –mca btl mx,self –np 2 pi3f90.x


However, if I give the command:

mpirun –np 2 pi3f90.x


The process runs normally. But, I do not know if it is using the Myrinet network.  Is there a way to diagnose this problem.  mpirun –v and –d do not seem to indicate which mca is actually being used.





Anthony C. Iannetti, P.E.

NASA Glenn Research Center

Propulsion Systems Division, Combustion Branch

21000 Brookpark Road, MS 5-10

Cleveland, OH 44135

phone: (216)433-5586



Please note:  All opinions expressed in this message are my own and NOT of NASA.  Only the NASA Administrator can speak on behalf of NASA.