Dear coll-group, some follow-up: On Tue, Feb 12, 2008 at 05:11:37PM -0500, Torsten Hoefler wrote:

c) Jesper has a paper about this on IPDPS

I have attached two papers. The first goes through some problems with especially graph topologies. Main points: a) specification is useless, because not scalable, b) there is too little information conveyed to the library, c) there could be different optimization criteria. Remedies are easy, deprecate old topology creation functions, make new scalable interface with weights and info-object. A quick and dirty implementation of new interface can trivially be done on top of old one. The second shows that even weights do not give enough information to let an MPI library do what the application wants. More radical remedy: take topologies out of MPI, but provide some functionality for getting "system independent" topology information ("distance" between processes and so on) for separate package. I would propose setting up a topology subgroup for these issues. We can discuss at the meeting, see if there's interest.

4) IU goes off and proposes better ideas, Jesper wants to join

very initial idea/question in separate mail to UI

5) Jesper writes proposal-like document

a first draft is attached. I would like to propose MPI_Reduce_scatter_block already for 2.2. About the new operators, I'm not even sure it is something I want to propose for real. What do you think? Are there need for anything else of this flavor?

6) contact mpi3-subsetting and see what they think

general things: - next meeting in March in Chicago - have proposals ready at leat one week before meeting in March - contact more application people (forward to Torsten) - contact Asian researchers (Jesper?) will not do more than what has already been done

best regards Jesper

The full recording (68:43) is available for private use (contact me).

Best, Torsten

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