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-rw-r--r--src/H5Fmpio.c94
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 */