Hi, Thanks. Interesting. I wonder in what relation this will stand with the ABI activity. Best regards. Alexander -----Original Message----- From: mpi3-subsetting-bounces_at_[hidden] [mailto:mpi3-subsetting-bounces_at_[hidden]] On Behalf Of Rainer Keller Sent: Wednesday, March 05, 2008 9:15 PM To: MPI3-Subsetting_at_[hidden] Subject: [Mpi3-subsetting] MPI3: Proposal to remove PMPI-Requirement Dear Alexander, dear all, at the previous Chicago meeting, some of us (Rich Graham, Jeff Squyres, Hubert Ritzdorf) have been discussing about the MPI-Standard's requirement to provide PMPI-functions for each MPI-Call into the library (except MPI_Wtime, MPI_Wtick). This is in my eyes a limitation: there could be some gains for the common case of large-scale applications: - Not using PMPI-based tools (dynamically loaded in) - Not using MPI_PROC_NULL - Not using MPI_STATUS_IGNORE So, if this proposal would fit Your definition of MPI3-Subsets, I would like to discuss the removal of the PMPI-function requirement, allowing inlining of MPI-functions and, based on that, pre-processor hints, e.g. MPI_HINT_NO_THREADS or MPI_HINT_NO_ANY_SOURCE, so the compiler might be able to eliminate several if-statements in the fast-path, allowing inlining, allowing dead code elimination. (of course, there is a whole lot of further issues involved, here -- please see the last section in the document). I have included some timings with NetPipe on Open MPI using these hints (further information section 4 -- Ompi Patch availble upon request, as its work in progress). Please take the timings with a grain of salt. I would like to get better figures on a more well-defined cluster environment. Any comments would be welcome. With best regards, Rainer -- ---------------------------------------------------------------- Dipl.-Inf. Rainer Keller http://www.hlrs.de/people/keller HLRS Tel: ++49 (0)711-685 6 5858 Nobelstrasse 19 Fax: ++49 (0)711-685 6 5832 70550 Stuttgart email: keller_at_[hidden] Germany AIM/Skype:rusraink --------------------------------------------------------------------- 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.