Hello Mr. Squyres, Team,


I know you guys are busy. Any attention to my questions will be mostly appreciated.

Is there a FAQ for mtt? May be some of my Q have been answered before.


I intend to run mtt and test some performance over Infiniband. My setup is a 2-Dell uni-core machines (i.e.: sw160,sw170) running SLES10.0. Each host has an Infiniband HCA Card installed. Each HCA Card has 2 Physical ports which are assigned unique IP’s (i.e.:, and, respectively)

Ports are connected back-to-back (port1 <-> port1 and port2 <-> port2)



Q #1: Can I override INI file value for hostlist in command line? If yes, please provide example.


Q #2: In your opinion, what should I specify to hostlist in order to run mpi jobs over my Infiniband fabric?

Is it hostlist = sw160 sw170

Is it hostlist =


Q #3: How do I determine which Interfaces mpi uses?



Q #4: How can I determine max num of processes for my setup? In the case of hostlist = sw160 sw170 , mtt will evaluate max_np to 2.

In the case of hostlist = , max_np will result to 4.


Q #5: I what terms can I ask mtt to use a local scratch directory on one of the host’ s hard drive  as oppose to some shared scratch folder on Network file system.


Shai Venter


Mellanox Technologies, Ltd.


+972 (0)4  9097200 ext. 252

+972 (0)50 2888637