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Do you MPI-2.2?

October 26, 2010 - 1 Comment

Open question to MPI developers: are you using the features added in MPI-2.2?

I ask because I took a little heat in the last MPI Forum meeting for not driving Open MPI to be MPI-2.2 compliant (Open MPI is MPI-2.1 compliant; there’s 4 open tickets that need to be completed for full MPI-2.2 compliance).

But I’m having a hard time finding users who want or need these specific functionalities (admittedly, they’re somewhat obscure).  We’ll definitely get to these items someday — the question is whether that someday needs to be soon or whether it can be a while from now.

Here’s a quick summary of what we have left to do:

  • #1368: We’re missing some C datatypes in the Fortran bindings, and vice versa.  Although to be fair, this is a pretty common problem across MPI implementations.  I guess no one has asked for this particular feature in a long, long time…
  • #2219: Add some new MPI datatypes (e.g., MPI_UINT8_T, MPI_AINT, …etc.).
  • #2221: Make MPI_EXSCAN support MPI_IN_PLACE.
  • #2223: Add the MPI_DIST_GRAPH_* functions.

All of these are Good Things, of course, but it’s a question of priority.  There’s a million other Good Things to do in Open MPI — which should we do first?  So far, the answer has been to do these four… er… not first.

Good decision?  Bad decision?  Let me know if you need this stuff.

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  1. 2219 is the only one which would bother me if I was allowed to use OpenMPI :-)