[OMPI users] "Hostfile" on Multicore Node?

[Jeff Pummill]

I am doing some testing on a variety of 8-core nodes in which I just 
want to execute a couple of executables and have them distributed to the 
available cores without overlapping. Typically, this would be done with 
a parameter like /-machinefile machines/, but I have no idea what names 
to put into the /machines/ file as this is a single node with two quad 
core cpu's. As I am launching the jobs sans scheduler, I need to specify 
what cores to run on I would think to keep from overscheduling some 
cores while others receive nothing to do at all.

Simple suggestions? Maybe Open MPI takes care of this detail for me?
Thanks!

Jeff Pummill