Creating a new comm

[Joshua Bernstein]

Pete,

Pete Wyckoff wrote:
> I'm not familiar with how mpich/bproc works.  You should take a
> look at the mpirun that comes with it, and at the MPID_Init function
> in mpid_bproc (or whatever).  If you have web pointers to these
> things, others can double check that you're headed in the right
> direction.

This is a helpful direction. Though how do I know what startup method my 
MPICH distribution is using? I know when MPICH is built its using 
--comm=bproc. Is this the startup method?

Otherwise, if I'm starting up just over Ethernet on Linux, are I just 
using ch_p4?

When I try starting up a an mpi job with mpiexec using --comm=p4, It 
seems to start the processes, but they just sit there. Likely waiting 
for a signal to tell them to start.

How can I figure out what MPICH is using for the startup method?

Another hint is that --comm=bproc changes RSHCOMMAND and RCP commands to 
Scyld specifics (bpsh and bpcp) is mpiexec using these commands at all?

In the end the problem I'm having is that when using mpiexec, I'm 
starting more processes then I need. For example consider:

qsub -l nodes=2:ppn=2
mpiexec ./myjob
^D

mpiexec actually starts up 4, 4 process tasks, rather then just 1, 4 
process task. Whats interesting is that if I do:

mpiexec -npernode 1 ./cpi
or
mpiexec -pernode ./cpi

I only get 2, 4 process jobs.

Any more thoughts or insights would be GREATLY appreciated.

-Josh