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From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2006-07-20 08:43:23


On 7/20/06 2:06 AM, "esaifu" <esaifu_at_[hidden]> wrote:

> I have been using openMPI for the last one month,so i need some clarification
> regrding the following points.
> 1). What is the advantage of OpenMPI over MPICH2 and LAM/MPI.I mean to say
> is there any difference in performace wise.

Open MPI's TCP performance is still a bit sub-par (because until only
recently, none of us had gotten around to optimizing it). It is probably
below MPICH's TCP performance and definitely below LAM's TCP performance.

There are still a few features that have not yet been ported to OMPI from
LAM (we're working on them -- TCP performance is one of them). But even
with those missing features, I consider OMPI to be a superior product than
LAM/MPI -- I have switched all my day-to-day MPI applications to use Open
MPI (instead of LAM). Indeed, since Open MPI was designed and built by --
among many others -- the LAM/MPI crew, it contains most of the great ideas
from LAM and is therefore (in my mind, at least ;-) ) a worthy successor.

I can say all these things about LAM because I was the technical lead for it
for many years, and therefore have pretty good insight in the comparison of
the two.

One of the main advantages of Open MPI is that it has different goals than
other MPI implementations. Open MPI aims to be a production-quality
software, is fully open source, strikes a good balance of cutting-edge
research and stability, and actively invites others to join in the process.
While there will always be bugs and "but with specific metric ABC, <insert
other MPI implementation> performs better than Open MPI!", we feel that the
above are critical characteristics that distinguish Open MPI from other
projects.

> 2). Any check pointing mechanism is there in OpenMPI like it is there in
> LAM/MPI.

Not yet. Work is actively progressing on this front. Search the mailing
list archives for mails from Josh Hursey for more details on this. The
short version is that we will have a demonstratable version of
checkpoint/restart at SC'06 (although it is highly unlikely that it will be
included in a stable release by then). The checkpoint/restart work that we
are doing in OMPI will far surpass what we did in LAM/MPI.

> 3) .Can i port the openMPI in any of the platform(X86,X86-64,ia64).

Yes.

-- 
Jeff Squyres
Server Virtualization Business Unit
Cisco Systems