Hi, Thanks. What subsets inside the current standard would you propose? What interfaces between them would you envision? Good idea about the optimization opportunities. Here's an initial combined list, with the main benefits as I see them. Please comment/extend. - Dynamic process support: less overhead in the progress engine, easier global rank handling. - Heterogeneity: better memory footprint, easier data handling. - Derived datatypes (especially those with holes): better memory footprint. - MPI_ANY_SOURCE: faster, more simple multifabric progress. - File I/O: smaller requests, easier wait/test functions. - One-sided ops: no passive target w/o MPI calls - no extra progress thread. - Communicator & group management: better memory footprint. - Message tagging: better support for stable dataflow exchanges, smaller packets. - Non-blocking communication: easier ordering, simplified request handling. Best regards. Alexander -----Original Message----- From: mpi3-subsetting-bounces_at_[hidden] [mailto:mpi3-subsetting-bounces_at_[hidden]] On Behalf Of Torsten Hoefler Sent: Friday, February 29, 2008 5:08 AM To: mpi3-subsetting_at_[hidden] Subject: 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 _______________________________________________ Mpi3-subsetting mailing list Mpi3-subsetting_at_[hidden] http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-subsetting --------------------------------------------------------------------- Intel GmbH Dornacher Strasse 1 85622 Feldkirchen/Muenchen Germany Sitz der Gesellschaft: Feldkirchen bei Muenchen Geschaeftsfuehrer: Douglas Lusk, Peter Gleissner, Hannes Schwaderer Registergericht: Muenchen HRB 47456 Ust.-IdNr. VAT Registration No.: DE129385895 Citibank Frankfurt (BLZ 502 109 00) 600119052 This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.