On Jul 31, 2012, at 2:58 AM, Eugene Loh wrote: > The main issue is this. If I go to ompi/mpi/fortran/mpif-h, I see six files > (*recv_f and *probe_f) that take status arguments. Normally, we do some > conversion between Fortran and C status arguments. These files test if > OMPI_SIZEOF_FORTRAN_INTEGER==SIZEOF_INT, however, and bypass the conversion > if the two types of integers are the same size. The problem with this is > that while the structures may be the same size, the C status has a size_t in > it. So, while the Fortran INTEGER array can start on any 4-byte alignment, > the C status can end up with a 64-bit pointer on a 4-byte alignment. That's > not pleasant in general and can incur some serious hand-slapping on SPARC. > Specifically, SPARC/-m64 errors out on *probe and *recv with MPI_PROC_NULL > sources. Would it be all right if I removed these "shorts cuts"?
Ew. Yes. You're right. What specifically do you propose? I don't remember offhand if the status conversion macros are the same as the regular int/INTEGER conversion macros -- we want to keep the no-op behavior for the regular int/INTEGER conversion macros and only handle the conversion of MPI_Status separately, I think. Specifically: for MPI_Status, we can probably still have those shortcuts for the int/INTEGERs, but treat the copying to the size_t separately. Thanks for fixing the ibm MPROBE tests, btw. Further proof that I must have been clinically insane when I added all those tests. :-( Related issue: do we need to (conditionally) add padding for the size_t in the Fortran array? > Here are two more smaller issues. I'm pretty sure about them and can make > the appropriate changes, but if someone wants to give feedback... > > 1) If I look at, say, the v1.7 MPI_Mprobe man page, it says: > > A matching probe with MPI_PROC_NULL as source returns > message = MPI_MESSAGE_NULL... > > In contrast, if I look at ibm/pt2pt/mprobe_mpifh.f90, it's checking the > message to be MPI_MESSAGE_NO_PROC. Further, if I look at the source code, > mprobe.c seems to set the message to "no proc". So, I take it the man page > is wrong? It should say "message = MPI_MESSAGE_NO_PROC"? Oh, yes -- I think the man page is wrong. The issue here is that the original MPI-3 proposal said to return MESSAGE_NULL, but this turns out to be ambiguous. So we amended the original MPI-3 proposal with the new constant MPI_MESSAGE_NO_PROC. So I think we fixed the implementation, but accidentally left the man page saying MESSAGE_NULL. If you care, here's the specifics: https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/38 https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/328 > 2) Next, looking further at mprobe.c, it looks like this: > > int MPI_Mprobe(int source, int tag, MPI_Comm comm, > MPI_Message *message, MPI_Status *status) > { > if (MPI_PROC_NULL == source) { > if (MPI_STATUS_IGNORE != status) { > *status = ompi_request_empty.req_status; > *message = &ompi_message_no_proc.message; > } > return MPI_SUCCESS; > } > ...... > } > > This means that if source==MPI_PROC_NULL and status==MPI_STATUS_IGNORE, the > message does not get set. The assignment to *message should be moved outside > the status check, right? Agreed. Good catch. Do the IBM MPROBE tests check for this condition? If not, we should probably extend them to do so. -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
