[Beowulf] MPI vs PVM

[Robert G. Brown]

On Mon, 3 Jan 2005, Stavros E. Zogas wrote:

> Hi at all
> I want to set up a beowulf cluster for scientific purposes (In a university)
> using mainly fortran compilers.I want your help to choose between MPI and
> PVM
> Thanks in Advance
> Stavros

This is an interesting choice.  MPI is likely more "portable" as it was
originally designed to be a common interface to big iron supercomputers
and is still a nearly universal parallel API for supercomputers of all
sorts, including beowulfish clusters.  MPI typically has support for
native hardware drivers for advanced networks as well, although this may
depend somewhate on the particular flavor of MPI you select (there are
several available).

PVM, OTOH, was from the beginning an open source project for building
possibly heterogeneous parallel HPC clusters.  There are (IIRC) some
drivers available for advanced networks, but support for this sort of
thing is a bit spottier.  If you've been doing cluster supercomputing
for more than a decade (noting that this means from before the "beowulf"
project itself got started, or at least was publicized) then chances are
pretty decent that you got started with PVM and still prefer it overall
today (according to my own VERY informal and anecdotal poll on the
issue).

If your plan is to use ethernet as a network and to write just one or
two simple applications, PVM is a pretty reasonable choice.  I provide a
PVM project template master/slave application, ready to build, on my
personal website here:

  http://www.phy.duke.edu/~rgb/General/project_pvm.php

However, it is in C.  However, the fortran interface is very similar, I
believe (I haven't willingly used fortran for nearly 20 years at this
point) and you could probably hack the template to make it a fortran
template with a bit of effort.

If you plan to use an advanced network, now or later, I'd have to
suggest that you use MPI.  It is also worth pointing out that there is a
regular MPI column in Cluster World Magazine, while PVM only gets
occassional attention from folks like me there (I wrote the template for
a CWM column).  However, I don't recall that it focusses on Fortran.

   rgb

-- 
Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu