[svn-r8125] Purpose:

    Bug fix/optimization

Description:
    Address slowdown in MPI-I/O file metadata operations that was introduced
mid-stream.  We now _require_ a POSIX compliant parallel file system for the
MPI-I/O file driver (as well as for the MPI-POSIX file driver).
    Also optimized file open operation when the file is being created by
reducing the number of collective & syncronizing calls.

Platforms tested:
    FreeBSD 4.9 (sleipnir) w/parallel
    h5committest

1 files changed, 4 insertions, 26 deletions

diff --git a/src/H5FDmpiposix.c b/src/H5FDmpiposix.c
index 8bca0bf..a51945d 100644
--- a/src/H5FDmpiposix.c
+++ b/src/H5FDmpiposix.c
@@ -224,17 +224,6 @@ static const H5FD_class_t H5FD_mpiposix_g = {
     H5FD_FLMAP_SINGLE 				/*fl_map		*/
 };
 
-#ifdef OLD_METADATA_WRITE
-/* Global var to allow elimination of redundant metadata writes
- * to be controlled by the value of an environment variable. */
-/* Use the elimination by default unless this is the Intel Red machine */
-#ifndef __PUMAGON__
-hbool_t	H5_mpiposix_1_metawrite_g = TRUE;
-#else
-hbool_t	H5_mpiposix_1_metawrite_g = FALSE;
-#endif
-#endif /* OLD_METADATA_WRITE */
-
 /* Interface initialization */
 #define PABLO_MASK	H5FD_mpiposix_mask
 #define INTERFACE_INIT	H5FD_mpiposix_init
@@ -1425,12 +1414,9 @@ H5FD_mpiposix_write(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr,
             if (MPI_SUCCESS!= (mpi_code=MPI_Barrier(file->comm)))
                 HMPI_GOTO_ERROR(FAIL, "MPI_Barrier failed", mpi_code);
 
-        /* Only p<round> will do the actual write if all procs in comm write same metadata */
-#ifdef OLD_METADATA_WRITE
-        if (H5_mpiposix_1_metawrite_g)
-#endif /* OLD_METADATA_WRITE */
-            if (file->mpi_rank != H5_PAR_META_WRITE)
-                HGOTO_DONE(SUCCEED) /* skip the actual write */
+        /* Only one process will do the actual write if all procs in comm write same metadata */
+        if (file->mpi_rank != H5_PAR_META_WRITE)
+            HGOTO_DONE(SUCCEED) /* skip the actual write */
     } /* end if */
 
 #ifdef REPORT_IO
@@ -1502,19 +1488,11 @@ done:
     } /* end if */
     /* Guard against getting into metadata broadcast in failure cases */
     else {
-#ifdef OLD_METADATA_WRITE
-        /* if only p<round> writes, need to broadcast the ret_value to other processes */
-        if ((type!=H5FD_MEM_DRAW) && H5_mpiposix_1_metawrite_g) {
-            if (MPI_SUCCESS != (mpi_code= MPI_Bcast(&ret_value, sizeof(ret_value), MPI_BYTE, H5_PAR_META_WRITE, file->comm)))
-                HMPI_GOTO_ERROR(FAIL, "MPI_Bcast failed", mpi_code);
-        } /* end if */
-#else /* OLD_METADATA_WRITE */
-        /* if only p<round> writes, need to broadcast the ret_value to other processes */
+        /* if only one process writes, need to broadcast the ret_value to other processes */
         if (type!=H5FD_MEM_DRAW) {
             if (MPI_SUCCESS != (mpi_code= MPI_Bcast(&ret_value, sizeof(ret_value), MPI_BYTE, H5_PAR_META_WRITE, file->comm)))
                 HMPI_GOTO_ERROR(FAIL, "MPI_Bcast failed", mpi_code);
         } /* end if */
-#endif /* OLD_METADATA_WRITE */
     } /* end else */
 
     FUNC_LEAVE_NOAPI(ret_value);