On Aug 27, 2015, at 3:25 AM, Gilles Gouaillardet <gil...@rist.or.jp> wrote:
>
> I am lost ...
Fortran does that to ya. ;-)
> from ompi/mpi/fortran/mpif-h/profile/palltoall_f.c
>
> void ompi_alltoall_f(char *sendbuf, MPI_Fint *sendcount, MPI_Fint *sendtype,
> char *recvbuf, MPI_Fint *recvcount, MPI_Fint *recvtype,
> MPI_Fint *comm, MPI_Fint *ierr)
> {
> [...]
> c_ierr = MPI_Alltoall(sendbuf,
> OMPI_FINT_2_INT(*sendcount),
> c_sendtype,
> recvbuf,
> OMPI_FINT_2_INT(*recvcount),
> c_recvtype, c_comm);
> [...]
> }
>
> $ nm ompi/mpi/fortran/mpif-h/profile/.libs/palltoall_f.o | grep MPI_Alltoall
> U MPI_Alltoall
> 0000000000000000 W MPI_Alltoall_f
> 0000000000000000 W MPI_Alltoall_f08
> 0000000000000000 W PMPI_Alltoall_f
> 0000000000000000 W PMPI_Alltoall_f08
>
> ompi_alltoall_f() calls MPI_Alltoall()
>
>
> the "natural" way of writing a tool is to write mpi_alltoall_ (that calls
> pmpi_alltoall_)
> *and* MPI_Alltoall (that calls PMPI_Alltoall)
Sidenote: the only correct way to write a tool that intercepts Fortran MPI API
calls is to write those interceptions *in Fortran*. I.e., the tool should
provide MPI_ALLTOALL as a Fortran subroutine. I realize that this is not the
point of what you are saying :-), but everyone always gets this point wrong, so
I feel the need to keep pointing this out.
> since ompi_alltoall_f invokes MPI_Alltoall (and not PMPI_Alltoall), the tool
> is invoked twice, by both the Fortran and C wrapper.
I didn't think that this was true, but I just confirmed it by looking at "gcc
-E" output in the mpif-h/profile directory.
I don't think that it was the intent. See below.
> my initial question was
> "why does ompi_alltoall_f invokes MPI_Alltoall instead of PMPI_Alltoall ?"
>
> /* since we share the same source code when building with or without mpi
> profiling,
> that means we would need to
> #define MPI_Alltoall PMPI_Alltoall
> when ompi is configure'd with --enable-mpi-profile
> */
I'm guessing that the complexity in the build system to support environments
without and with weak symbols (i.e., OS X vs. just about everyone else) have
made this get lost over time.
Can you supply a patch?
--
Jeff Squyres
jsquy...@cisco.com
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