[Mpi3-tools] Standardized MPI_COMM_WORLD rank environment variable?

[Jeffrey Squyres]

On Apr 24, 2012, at 5:36 PM, Dries Kimpe wrote:

>> Any kind of unique value would allow the tool to have a unique, safe filename.
> 
> What about a tmpnam for MPI then :-)
> 
> No need to bring details like rank->thread->process mapping into this if
> all you want is a guaranteed unique filename among the MPI ranks of the
> application.


You do want it to be able to be mapped back to individual MPI (and/or OS) processes, though.  MCW rank is a pretty easy way to identify things.  

If it weren't for this desire, PID would be sufficient.  But users find it to be a PITA to map PID back to whatever MCW rank it was.  That's why tools are looking for MPI-specific information that is meaningful to the user.

FWIW: Also add Valgrind to the list of tools that Rayson mentioned (there's an option to suffix the valgrind output files with the MCW rank).

-- 
Jeff Squyres
jsquyres at cisco.com
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