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Diffstat (limited to 'src/H5Fmpio.c')
| -rw-r--r-- | src/H5Fmpio.c | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/src/H5Fmpio.c b/src/H5Fmpio.c index b12072b..a9ac303 100644 --- a/src/H5Fmpio.c +++ b/src/H5Fmpio.c @@ -992,5 +992,99 @@ H5F_haddr_to_MPIOff( haddr_t addr, MPI_Offset *mpi_off ) return (ret_val); } + +/*------------------------------------------------------------------------- + * Function: H5PC_Wait_for_left_neighbor + * + * Purpose: Blocks until (empty) msg is received + * from immediately lower-rank neighbor. + * In conjunction with Signal_right_neighbor, + * useful for enforcing 1-process-at-at-time access + * to critical regions to avoid race conditions + * (though it is overkill to require that the processes + * be allowed to proceed strictly in order of their rank). + * + * NOTE: This routine doesn't read or write any file, + * just performs interprocess coordination. + * It really should reside in a separate package of such routines. + * + * Return: Success: SUCCEED + * Failure: FAIL + * + * Programmer: rky + * 19981207 + * + * Modifications: + * + *------------------------------------------------------------------------- + */ +herr_t +H5PC_Wait_for_left_neighbor( MPI_Comm comm ) +{ + char msgbuf[1]; + int myid, mpi_err; + MPI_Status rcvstat; + + FUNC_ENTER (H5PC_Wait_for_left_neighbor, FAIL); + + mpi_err = MPI_Comm_rank( comm, &myid ); + if (MPI_SUCCESS!=mpi_err) + HRETURN_ERROR(H5E_IO, H5E_MPI, FAIL, "MPI_Comm_rank failed"); + /* p0 has no left neighbor; all other procs wait for msg */ + if (myid != 0) { + mpi_err = MPI_Recv( &msgbuf, 1, MPI_CHAR, myid-1, MPI_ANY_TAG, comm, + &rcvstat ); + if (MPI_SUCCESS!=mpi_err) + HRETURN_ERROR(H5E_IO, H5E_MPI, FAIL, "MPI_Recv failed"); + } + FUNC_LEAVE (SUCCEED); +} /* H5PC_Wait_for_left_neighbor */ + +/*------------------------------------------------------------------------- + * Function: H5PC_Signal_right_neighbor + * + * Purpose: Blocks until (empty) msg is received + * from immediately lower-rank neighbor. + * In conjunction with Wait_for_left_neighbor, + * useful for enforcing 1-process-at-at-time access + * to critical regions to avoid race conditions + * (though it is overkill to require that the processes + * be allowed to proceed strictly in order of their rank). + * + * NOTE: This routine doesn't read or write any file, + * just performs interprocess coordination. + * It really should reside in a separate package of such routines. + * + * Return: Success: SUCCEED + * Failure: FAIL + * + * Programmer: rky + * 19981207 + * + * Modifications: + * + *------------------------------------------------------------------------- + */ +herr_t +H5PC_Signal_right_neighbor( MPI_Comm comm ) +{ + char msgbuf[1]; + int myid, numprocs, mpi_err; + + FUNC_ENTER (H5PC_Signal_right_neighbor, FAIL); + + mpi_err = MPI_Comm_size( comm, &numprocs ); + if (MPI_SUCCESS!=mpi_err) + HRETURN_ERROR(H5E_IO, H5E_MPI, FAIL, "MPI_Comm_rank failed"); + mpi_err = MPI_Comm_rank( comm, &myid ); + if (MPI_SUCCESS!=mpi_err) + HRETURN_ERROR(H5E_IO, H5E_MPI, FAIL, "MPI_Comm_rank failed"); + if (myid != (numprocs-1)) { + mpi_err = MPI_Send( &msgbuf, 0/*empty msg*/, MPI_CHAR, myid+1, 0, comm); + if (MPI_SUCCESS!=mpi_err) + HRETURN_ERROR(H5E_IO, H5E_MPI, FAIL, "MPI_Send failed"); + } + FUNC_LEAVE (SUCCEED); +} /* H5PC_Signal_right_neighbor */ #endif /* HAVE_PARALLEL */ |