[mpich-discuss] Problem with spawning child with same executable name

[Pavan Balaji]

On 02/09/2011 04:06 PM, Yauheni Zelenko wrote:
> Then I run program with Hydra: mpiexec -host "host1:2,host2:2"
>
> Master process is run on host1. At first spawn 1 child was run on
> host1 and 2 on host2, but on consequent spawns, 2 children was on
> host1 and 1 on host2.
>
> I think such resources allocation may create balancing problems and
> Hydra should not spawn children processes on hosts still in use.

That sound correct to me. Hydra looks at the host list as:

host1, host1, host2, host2, ..., [wrap around].

The master process is launched on the first "host1". When you spawn 
three processes the first time, it launches them on "host1", "host2", 
and "host2". When you spawn three processes the second time, it launches 
them on "host1", "host1", "host2". The next spawn of three processes 
will be "host2", "host1", "host1", etc.

  -- Pavan

-- 
Pavan Balaji
http://www.mcs.anl.gov/~balaji