Re: [Mpi3-subsetting] agenda for subsetting kickoff telecon ww09
Hi,
Present: Leonid Meyerguz (Microsoft), Rich Graham (ORNL), Richard Barrett (ORNL), Torsten Hoefler (ISU), Alexander Supalov (Intel) just for the record, it's "IU" not "ISU" :-)
- Scope of the effort - Rich - Minimum subset consistent with the rest of MPI, for performance/memory footprint optimization - Danger of splitting MPI, hence against optional features in the standard I back that (danger of optional features for portability). I'd propose to split the current standard into mostly self-contained subsets that have clearly defined interfaces to the rest of the standard. Note: this only defines logical interfaces, that does *not* define how those things are to be implemented. This makes it easier to understand the standard and have separate (portable) libraries for the subsets, it does not influence optimization possibilities by implementing everything in a monolithic block (i.e., central progress).
- Both blocking & nonblocking belong to the core - Torsten - Some collectives may go into selectable subsets
I see three subsets: blocking colls, non-blocking colls and topological colls (maybe also blocking / non-blocking).
- MPI_ANY_SOURCE considered harmful
I'd like to add datatypes and heterogeneity to this list (with regards to performance). Alexander mentioned the dynamics. I think we should have a lit of items ready that could influence optimization possibilities significanty if they were to be announced by the user before he can use them. That would give another strong argument for the subsetting. Best, Torsten -- bash$ :(){ :|:&};: --------------------- http://www.unixer.de/ ----- Indiana University | http://www.indiana.edu Open Systems Lab | http://osl.iu.edu/ 150 S. Woodlawn Ave. | Bloomington, IN, 474045-7104 | USA Lindley Hall Room 135 | +01 (812) 855-3608
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