Newsgroups: comp.parallel.mpi
From: rdaoud@magnus.acs.ohio-state.edu (Raja B Daoud)
Subject: Re: Any current implementation supports dynamic sets of processors?
Organization: Ohio Supercomputer Center
Date: 23 May 1995 20:40:12 GMT
Message-ID: <3pth7c$epr@charm.magnus.acs.ohio-state.edu>

Thilo Kielmann <kielmann@informatik.uni-siegen.de> wrote:
>I understood that handling process sets shall be topic of MPI2, but:
>Is there any obstacle in currently existing implementations which prevent
>new processes from joining (or leaving) running systems?

LAM 5.2 (current version) does not support dynamic MPI processes.  The
next version, scheduled to be released at the MPI users group meeting
next month, will provide the spawn functionality as an extension.  This
early support for spawning (before MPI-2) will allow us to collect user
feedback.

The current obstacle is the lack of support for creating new worlds and
allowing processes to recognize each other.  Just replacing mpirun won't
do the trick, processes have to be notified of the changes in the system
at runtime.  One way to do this is to make spawn a collective operation,
providing a tie between the new group of processes and the parent group.

--Raja

-=-
Raja Daoud				raja@tbag.osc.edu
Ohio Supercomputer Center		http://www.osc.edu/lam.html

