[svn-r12090] Purpose:

New APIs to add for collective chunk IO

Description:
Three new APIs
H5Pset_dxpl_mpio_chunk_opt_ratio
H5Pset_dxpl_mpio_chunk_opt_num
H5Pset_dxpl_mpio_chunk_opt

for optional optimization choices from users.
Solution:
Haven't added tests yet, won't affect other parts of the library.
Will add tests after urgent investigations of memory leaking problems from NASA Aura team.
Platforms tested:
heping: both parallel and sequential
shanti
Misc. update:

1 files changed, 22 insertions, 0 deletions

diff --git a/src/H5FDmpi.h b/src/H5FDmpi.h
index aac7bf6..c9da439 100644
--- a/src/H5FDmpi.h
+++ b/src/H5FDmpi.h
@@ -21,12 +21,34 @@
 #ifndef H5FDmpi_H
 #define H5FDmpi_H
 
+/***** Macros for One linked collective IO case. *****/ 
+/* The default value to do one linked collective IO for all chunks. 
+   If the average number of chunks per process is greater than this value,
+      the library will create an MPI derived datatype to link all chunks to do collective IO.
+      The user can set this value through an API. */
+
+#define H5D_ONE_LINK_CHUNK_IO_THRESHOLD 0
+/***** Macros for multi-chunk collective IO case. *****/
+/* The default value of the threshold to do collective IO for this chunk.
+   If the average number of processes per chunk is greater than the default value,
+   collective IO is done for this chunk.
+*/
+
+#define H5D_MULTI_CHUNK_IO_COL_THRESHOLD 50
 /* Type of I/O for data transfer properties */
 typedef enum H5FD_mpio_xfer_t {
     H5FD_MPIO_INDEPENDENT = 0, 		/*zero is the default*/
     H5FD_MPIO_COLLECTIVE
 } H5FD_mpio_xfer_t;
 
+/* Type of I/O for data transfer properties */
+typedef enum H5FD_mpio_chunk_opt_t {
+    H5FD_MPIO_OPT_IGNORE = 0,
+    H5FD_MPIO_OPT_ONE_IO,  		/*zero is the default*/
+    H5FD_MPIO_OPT_MULTI_IO
+} H5FD_mpio_chunk_opt_t;
+
+
 #ifdef H5_HAVE_PARALLEL
 
 /* Sub-class the H5FD_class_t to add more specific functions for MPI-based VFDs */