(For some reason, my copy of Pavan's message is blank, so I'm replying to this one). There are a number of things about this approach that make me uneasy. In the short term, its probably ok (modulo some of the naming issues, particularly avoiding reserved MPI names and using MPIR_Pint instead of MPI_Pint, etc.), but in the long run (MPI 3?) we need to do something else. An example is the changes to the attribute routines - that's the sort of unintended side effect that I expect to cause problems in some peoples codes. My feeling is this: We need to make sure that the macros/types meet the naming rules and do not appear in mpi.h , where users might see them (they can be in mpiimpl.h or in a new file that configure creates that mpiimpl.h includes). We should think about whether we really want to specify the size of MPI_Aint or simply say that MPI_Aint and MPI_Offset are the same size, and the size is the max of what is needed (address, file offset). Bill On May 3, 2008, at 10:28 AM, Rob Ross wrote:
Hey,
Sorry for the "I/I" instead of "I/O"...iPhone is trying to be helpful.
At a conceptual level these patches are something that I think that we want to integrate, but your take on the specifics obviously trumps this conceptual need in the short term :).
Thanks!
Rob
On May 3, 2008, at 12:33 AM, Pavan Balaji wrote:
Maybe you haven't been in on the conversation related to this? The issue is that MPI_Aint is the size for extents, even in I/I space, and so we need it to be 64 bit to be able to do useful file I/I (think subarray access from many processes).
Ah, got it. Thanks. I saw this discussion earlier, but couldn't pin- point the reason. So, we do want to accept the MPI_AINT_TO_VOID_PTR and family related parts of the patches, correct?
We'll probably also need to go through the entire code to make sure there are no random typecasts from MPI_Aint to (void *); the other way should be fine.
-- Pavan
-- Pavan Balaji http://www.mcs.anl.gov/~balaji
William Gropp Paul and Cynthia Saylor Professor of Computer Science University of Illinois Urbana-Champaign