[svn-r5390] Purpose:

    Code cleanup

Description:
    The parallel I/O file driver is optimized to only write metadata with one
    process (and broadcast the results to the other processes).  This is
    currently enabled by a separate call to H5FD_mpio_tas_allsame() before
    each metadata write to the file.  This can easily lead to problems where
    the prelude function call is omitted before the actual write code or, in
    a threaded environment, lead to race condititions where the value set is
    reset before being used.

Solution:
    Since we only want to write metadata from one process, key off of the 'type'
    parameter (which has information about whether the data being written it
    metadata or raw data) to H5FD_mpio_write() as the method for determining
    whether to only write from one process or not.

Platforms tested:
    IRIX64 6.5 (modi4)

1 files changed, 11 insertions, 48 deletions

diff --git a/src/H5FDmpio.c b/src/H5FDmpio.c
index 0f1be8d..2d28828 100644
--- a/src/H5FDmpio.c
+++ b/src/H5FDmpio.c
@@ -55,7 +55,6 @@ 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) */
-    hbool_t	allsame;	/*same data for all procs?		*/
     haddr_t	eof;		/*end-of-file marker			*/
     haddr_t	eoa;		/*end-of-address marker			*/
     MPI_Datatype btype;		/*buffer type for xfers			*/
@@ -421,48 +420,6 @@ H5Pget_dxpl_mpio(hid_t dxpl_id, H5FD_mpio_xfer_t *xfer_mode/*out*/)
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5FD_mpio_tas_allsame
- *
- * Purpose:     Test and set the allsame parameter.
- *
- * Return:      Success:        the old value of the allsame flag
- *
- *              Failure:        assert fails if access_parms is NULL.
- *
- * Programmer:  rky 980828
- *
- * Modifications:
- *
- *-------------------------------------------------------------------------
- */
-htri_t
-H5FD_mpio_tas_allsame(H5FD_t *_file, hbool_t newval)
-{
-    H5FD_mpio_t	*file = (H5FD_mpio_t*)_file;
-    hbool_t	oldval;
-
-    FUNC_ENTER(H5FD_mpio_tas_allsame, FAIL);
-
-#ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-    	fprintf(stdout, "Entering H5FD_mpio_tas_allsame, newval=%d\n", newval);
-#endif
-
-    assert(file);
-    assert(H5FD_MPIO==file->pub.driver_id);
-    oldval = file->allsame;
-    file->allsame = newval;
-
-#ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-    	fprintf(stdout, "Leaving H5FD_mpio_tas_allsame, oldval=%d\n", oldval);
-#endif
-
-    FUNC_LEAVE(oldval);
-}
-
-
-/*-------------------------------------------------------------------------
  * Function:	H5FD_mpio_communicator
  *
  * Purpose:	Returns the MPI communicator for the file.
@@ -1336,10 +1293,18 @@ H5FD_mpio_read(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t dxpl_id, haddr_t add
  *		Kim Yates, Pat Weidhaas,  2000-09-26
  *		Move block of coding where only p0 writes after the
  *              MPI_File_set_view call. 
+ *
+ *		Quincey Koziol,  2002-05-10
+ *		Instead of always writing metadata from process 0, spread the
+ *              burden among all the processes by using a round-robin rotation
+ *              scheme.
+ *
+ *		Quincey Koziol,  2002-05-10
+ *		Removed allsame code, keying off the type parameter instead.
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5FD_mpio_write(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t dxpl_id, haddr_t addr,
+H5FD_mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr,
 		size_t size, const void *buf)
 {
     H5FD_mpio_t			*file = (H5FD_mpio_t*)_file;
@@ -1350,7 +1315,6 @@ H5FD_mpio_write(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t dxpl_id, haddr_t ad
     MPI_Datatype		buf_type, file_type;
     int         		size_i, bytes_written;
     int				use_types_this_time, used_types_last_time;
-    hbool_t     		allsame;
     H5P_genplist_t *plist;      /* Property list pointer */
     herr_t              	ret_value=SUCCEED;
 
@@ -1436,8 +1400,7 @@ H5FD_mpio_write(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t dxpl_id, haddr_t ad
     file->use_types = 0;
 
     /* Only p<round> will do the actual write if all procs in comm write same data */
-    allsame = H5FD_mpio_tas_allsame(_file, FALSE);
-    if (allsame && H5_mpi_1_metawrite_g) {
+    if ((type!=H5FD_MEM_DRAW) && H5_mpi_1_metawrite_g) {
         if (file->mpi_rank != file->mpi_round) {
 #ifdef H5FDmpio_DEBUG
             if (H5FD_mpio_Debug[(int)'w']) {
@@ -1504,7 +1467,7 @@ H5FD_mpio_write(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t dxpl_id, haddr_t ad
     
 done:
     /* if only p<round> writes, need to broadcast the ret_value to other processes */
-    if (allsame && H5_mpi_1_metawrite_g) {
+    if ((type!=H5FD_MEM_DRAW) && H5_mpi_1_metawrite_g) {
 	if (MPI_SUCCESS !=
 	    MPI_Bcast(&ret_value, sizeof(ret_value), MPI_BYTE, file->mpi_round, file->comm))
           HRETURN_ERROR(H5E_INTERNAL, H5E_MPI, FAIL, "MPI_Bcast failed");