[Beowulf] The Case for an MPI ABI

Joachim Worringen joachim at ccrl-nece.de
Thu Feb 24 07:45:27 PST 2005

Ashley Pittman wrote:
> 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.

My experience is that such sites want to use their (expensive, 
commercial, Fortran) compiler to optimize the binaries to their 
platform. In some cases, this requires source-code changes (parameters) 
anyway. It's not about PMB.

> 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

I can't see where I made this assumption. Indeed, most interconnect 
vendors (Quadrics, various Infiniband, Myrinet, ...) happily plug their 
low-level stuff into the latest MPICH and are done. So, it's most often 
the cross-interconnect MPI vendors which create their own ABI for some 
reason. Other cases are vendors (like us) who started to provide MPI-2 
when there was no open-source MPI-2 around. We had to do our own 
definitions then.

But this doesn't really matter after all; what matters is if there are 
enough parties to take part in this effort, and to understand the 
related issues as much as possible and as early as possible.


Joachim Worringen - NEC C&C research lab St.Augustin
fon +49-2241-9252.20 - fax .99 - http://www.ccrl-nece.de

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