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

[Yauheni Zelenko]

But there is still living process on host1. I think accounting fact this will be more correct Hydra behaviour.

Eugene.
________________________________________
From: Pavan Balaji [balaji at mcs.anl.gov]
Sent: Wednesday, February 09, 2011 2:11 PM
To: mpich-discuss at mcs.anl.gov
Cc: Yauheni Zelenko
Subject: Re: [mpich-discuss] Problem with spawning child with same executable name

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