Newsgroups: comp.parallel.mpi
From: smith@epcc.ed.ac.uk (A Gordon Smith)
Subject: Re: Any current implementation supports dynamic sets of processors?
Organization: Edinburgh Parallel Computing Centre
Date: Thu, 25 May 1995 18:22:53 GMT
Message-ID: <D95CE5.MCz@dcs.ed.ac.uk>

In article <3q27ss$gas@oak64.doc.ic.ac.uk>, arw1@doc.ic.ac.uk (Andrew Roger Ward) writes:
> 
> Hello All,
> 
> I have just downloaded the CHIMP MPI code, and I want to use it for
> communication between processes running on different processors.  The
> examples given only concern multiple processes running on one (the local)
> machine.  Does anyone have some (fairly simple) example code that I could
> look at, for running communicating jobs on more than one machine?
> 
> Thanks very much
> 
> Andrew
> 

Hello Andrew and all,

For CHIMP/MPI to run processes over a UNIX network you have to attach
host names  to the relevant processes within the configuration file, or
else, as you observe, all processes run on the local host. On MPPs,
CHIMP/MPI will run each process on a separate processor, and on Meiko
T800 CS-1 it's even possible to run multiple (different) executables on
the same processor, if you really want to..

What you really want is an example CHIMP/MPI configuration file:

  2 (A.exe)
  2 (B.exe) : host=other

This will run 2 processes executing "./A.exe" on the local host, and
2 processes executing "./B.exe" on the remote host with hostname "other".

This assumes that you have set up .rhosts to allow rsh from local to
"other" and that you don't have to change user, working directory, &c.
Check out the User Guide ("doc/user.ps" in the CHIMP/MPI release) for
more info, or e-mail <chimp@epcc.ed.ac.uk> if there are problems.

I'll say now that there are no plans to support dynamic process
management in CHIMP/MPI. We did consider such things in the last CHIMP
interface design though: spawning "blobs" of processes, barrier on
process group size. The MPI-2 draft proposals are encouragingly familiar,
and we're very interested in MPI's development in this area.


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 -=-=- A. Gordon Smith -=- Edinburgh Parallel Computing Centre -=-=-
 =-= Email <smith@epcc.ed.ac.uk> -=- Phone {+44 (0)131 650 6712} =-=
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