Re: [openMosix-general] MPI

[Robin N . T. <rn...@br...>]

In fact I used one of the programs in the LAM-MPI test suite on the 
wanglab cluster and it worked like a charm. Can't tell you about 
performance increases, but I can tell you that it seems that 
setting up MPICH is much simpler, as compared to LAM-MPI; used 
LAM-MPI anyway because that was requested.

As Moshe already said, they work together very well.

Shabbat shalom to everybody and a good weekend to all others,

-Robin


* on the Fri, Aug 02, 2002 at 01:53:21PM -0400, Abraham Schneider was saying:
> Hello,
> 
> My lab is currently experimenting with software for running on our
> beowulf cluster. We first tried PBS, after being told it was the defacto
> standard, but had to switch because a queue system does not really fit
> our needs. openMosix seems like the perfect approach for us to take, it
> works wonderfully (so far, anyways), and it makes life much much easier.
> 
> Most of our computational work is done using a simple method of having
> the same program run many times over on different sections of a data set
> (usually octave or matlab [which we are quickly switching away from
> since it does not seem to play nicely with openMosix]).
> 
> Anyways, my question is this. Currently I'm working on a evolution
> computer library to work on the cluster for fitting models to
> experimental data. I would _very_ much like to use MPI, since in the
> past I had to write my own TCP/IP code for message passing. After
> talking with someone from a different lab I was told that MPI and
> openMOSIX may not play nicely together (i.e. its okay, as long as you
> lock spawned jobs to a specific node). I have looked everywhere for more
> info, including this mailing list, but I haven't found enough
> information on the subject. What are the complications to running MPI on
> openMosix, do I have to write my programs differently to take anything
> into account, where can I find more information on this subject. One
> item I did find in the mailing list was someone claiming that I should
> not use MPI if I use openMosix (if so, is there another good message
> passing library out there to use?), but Moshe responded with:
> 
> moshe> Agree with everything except that openMosix (can we please call
> it that
> moshe> way? OM is ugly ) does not come into the way of MPI *at all*. In
> fact,
> moshe> openMosix can only be beneficiary for MPI. MPI just executes
> through rsh
> moshe> jobs on a remote node. With openMosix if that remote node is too
> busy, moshe> that job will migrate to a better node.
> 
> I understand that this question might be better suited for the MPICH or
> LAM mailing lists (btw, if MPI does work, does it matter how well it
> plays with openMosix depend on the implementation?), but I found even
> less information on their web pages.
> 
> 
> Thanks,
> 
> Abe