[svn-r5408] Purpose:

    Performance enhancement

Description:
    Doing an MPI_File_sync() just before a file is closed causing a large
    performance loss.

Solution:
    Add flag to MPI file driver to avoid performance the MPI_File_sync() when
    the flag is set before a call to H5F_flush().

Platforms tested:
    IRIX64 6.5 (modi4)

3 files changed, 48 insertions, 2 deletions

diff --git a/src/H5F.c b/src/H5F.c
index 470f993..4021c22 100644
--- a/src/H5F.c
+++ b/src/H5F.c
@@ -2622,6 +2622,12 @@ H5F_close(H5F_t *f)
 	H5AC_debug(f);
 	H5F_istore_stats(f, FALSE);
 
+#ifdef H5_HAVE_PARALLEL
+        if(IS_H5FD_MPIO(f)) {
+            if (SUCCEED!= H5FD_mpio_closing(f->shared->lf))
+                HRETURN_ERROR (H5E_IO, H5E_CANTFLUSH, FAIL, "unable to set 'closing' flag");
+        } /* end if */
+#endif /* H5_HAVE_PARALLEL */
 	/* Flush and destroy all caches */
 	if (H5F_flush(f, H5F_SCOPE_LOCAL, TRUE, FALSE)<0)
 	    HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, "unable to flush cache");
diff --git a/src/H5FDmpio.c b/src/H5FDmpio.c
index fdf39ad..585aa47 100644
--- a/src/H5FDmpio.c
+++ b/src/H5FDmpio.c
@@ -55,6 +55,7 @@ typedef struct H5FD_mpio_t {
     int         mpi_rank;       /* This process's rank                  */
     int         mpi_size;       /* Total number of processes            */
     int         mpi_round;      /* Current round robin process (for metadata I/O) */
+    unsigned    closing;        /* Indicate that the file is closing immediately after call to flush */
     haddr_t	eof;		/*end-of-file marker			*/
     haddr_t	eoa;		/*end-of-address marker			*/
     MPI_Datatype btype;		/*buffer type for xfers			*/
@@ -579,6 +580,37 @@ H5FD_mpio_signal_right_neighbor(H5FD_t *_file)
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5FD_mpio_closing
+ *
+ * Purpose:	Indicate that next flush call is immediately prior to a
+ *              close on the file.
+ *
+ * Return:	Success: non-negative
+ *		Failure: negative
+ *
+ * Programmer:	Quincey Koziol, May 13, 2002
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5FD_mpio_closing(H5FD_t *_file)
+{
+    H5FD_mpio_t	*file = (H5FD_mpio_t*)_file;
+
+    FUNC_ENTER(H5FD_mpio_closing, FAIL);
+    assert(file);
+    assert(H5FD_MPIO==file->pub.driver_id);
+
+    /* Set the 'closing' flag for this file */
+    file->closing=TRUE;
+    
+    FUNC_LEAVE(SUCCEED);
+}
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5FD_mpio_fapl_get
  *
  * Purpose:	Returns a file access property list which could be used to
@@ -787,6 +819,7 @@ H5FD_mpio_open(const char *name, unsigned flags, hid_t fapl_id,
     file->mpi_rank = mpi_rank;
     file->mpi_size = mpi_size;
     file->mpi_round = 0;        /* Start metadata writes with process 0 */
+    file->closing = FALSE;      /* Not closing yet */
     file->btype = MPI_DATATYPE_NULL;
     file->ftype = MPI_DATATYPE_NULL;
 
@@ -1563,8 +1596,14 @@ H5FD_mpio_flush(H5FD_t *_file)
         }
     }
 
-    if (MPI_SUCCESS != (mpi_code=MPI_File_sync(file->f)))
-        HMPI_GOTO_ERROR(FAIL, "MPI_File_sync failed", mpi_code);
+    /* Only sync the file if we are not going to immediately close it */
+    if(!file->closing) {
+        if (MPI_SUCCESS != (mpi_code=MPI_File_sync(file->f)))
+            HMPI_GOTO_ERROR(FAIL, "MPI_File_sync failed", mpi_code);
+    } /* end if */
+
+    /* Reset 'closing' flag now */
+    file->closing=FALSE;
 
 done:
 #ifdef H5FDmpio_DEBUG
diff --git a/src/H5FDmpio.h b/src/H5FDmpio.h
index 08dd857..425a346 100644
--- a/src/H5FDmpio.h
+++ b/src/H5FDmpio.h
@@ -61,6 +61,7 @@ __DLL__ herr_t H5FD_mpio_setup(H5FD_t *_file, MPI_Datatype btype, MPI_Datatype f
 		       haddr_t disp, hbool_t use_types);
 __DLL__ herr_t H5FD_mpio_wait_for_left_neighbor(H5FD_t *file);
 __DLL__ herr_t H5FD_mpio_signal_right_neighbor(H5FD_t *file);
+__DLL__ herr_t H5FD_mpio_closing(H5FD_t *file);
 #ifdef __cplusplus
 }
 #endif