[Beowulf] The Case for an MPI ABI

[Ashley Pittman]

On Thu, 2005-02-24 at 14:30 +0100, Joachim Worringen wrote:

> For open source software packages alone, an ABI is not of critical 
> importance as people with a tcp/ip cluster can use pre-linkked packages, 
> and people with a high-perfomance interconnect cluster typically have 
> enough competence to compile the software themselves.

It's not about competence, it's about time and effort spent.  I wouldn't
need to compile every application myself if there was a ABI.  It's not a
particularly difficult thing to do, it just going through the hoops of
doing it every time you need an application.  The ability to install a
cluster and type '[apt-get|yum] install pmb' would be a truly wonderful
thing indeed.

You also make the assumption that it's the high-performance vendors who
do things differently, I don't believe this is the case.  Quadrics for
example (my employer) happen to use whatever ABI MPICH (1.2.x) provides
as we have never had a reason to modify it.  I believe the same holds
for Myrinet, I've certinally run binaries compiled against Myrinet MPI
on our MPI stack without obvious problems.  Having said that though I
have never attempted to verify binary compatibility and we don't support
such programs but insist they are correctly compiled before support
requests get more than a cursory glance.

Ashley,