[svn-r19097] Description:

	Bring r19096 from trunk to 1.8 branch:

	Bring "round robin" metadata write strategy code from 'round_robin'
branch to the trunk.

Tested on:
       FreeBSD/32 6.3 (duty) in debug mode
       FreeBSD/64 6.3 (liberty) w/C++ & FORTRAN, in debug mode
       Linux/32 2.6 (jam) w/PGI compilers, w/default API=1.8.x,
               w/C++ & FORTRAN, w/threadsafe, in debug mode
       Linux/64-amd64 2.6 (amani) w/Intel compilers, w/default API=1.6.x,
               w/C++ & FORTRAN, in production mode
       Solaris/32 2.10 (linew) w/deprecated symbols disabled, w/C++ & FORTRAN,
               w/szip filter, in production mode
       Linux/64-ia64 2.6 (cobalt) w/Intel compilers, w/C++ & FORTRAN,
               in production mode
       Linux/64-amd64 2.6 (abe) w/parallel, w/FORTRAN, in debug mode
       Mac OS X/32 10.6.3 (amazon) in debug mode
       Mac OS X/32 10.6.3 (amazon) w/C++ & FORTRAN, w/threadsafe,
               in production mode

1 files changed, 66 insertions, 0 deletions

diff --git a/src/H5ACpkg.h b/src/H5ACpkg.h
index d5346f5..3060a70 100644
--- a/src/H5ACpkg.h
+++ b/src/H5ACpkg.h
@@ -46,6 +46,17 @@
 
 #define H5AC_DEBUG_DIRTY_BYTES_CREATION	0
 
+#ifdef H5_HAVE_PARALLEL
+
+/* the following #defined are used to specify the operation required
+ * at a sync point.
+ */
+
+#define H5AC_SYNC_POINT_OP__FLUSH_TO_MIN_CLEAN		0
+#define H5AC_SYNC_POINT_OP__FLUSH_CACHE			1
+
+#endif /* H5_HAVE_PARALLEL */
+
 /*-------------------------------------------------------------------------
  *  It is a bit difficult to set ranges of allowable values on the
  *  dirty_bytes_threshold field of H5AC_aux_t.  The following are
@@ -59,6 +70,9 @@
 #define H5AC__MAX_DIRTY_BYTES_THRESHOLD   	(int32_t) \
 						(H5C__MAX_MAX_CACHE_SIZE / 4)
 
+#define H5AC__DEFAULT_METADATA_WRITE_STRATEGY	\
+				H5AC_METADATA_WRITE_STRATEGY__DISTRIBUTED
+
 /****************************************************************************
  *
  * structure H5AC_aux_t
@@ -162,6 +176,12 @@
  *		broadcast.  This field is reset to zero after each such
  *		broadcast.
  *
+ * metadata_write_strategy: Integer code indicating how we will be 
+ *		writing the metadata.  In the first incarnation of 
+ *		this code, all writes were done from process 0.  This
+ *		field exists to facilitate experiments with other 
+ *		strategies.
+ *
  * dirty_bytes_propagations: This field only exists when the
  *		H5AC_DEBUG_DIRTY_BYTES_CREATION #define is TRUE.
  *
@@ -211,6 +231,19 @@
  *		been created via move operations since the last time
  *		the cleaned list was propagated.
  *
+ * Things have changed a bit since the following four fields were defined.
+ * If metadata_write_strategy is H5AC_METADATA_WRITE_STRATEGY__PROCESS_0_ONLY,
+ * all comments hold as before -- with the caviate that pending further 
+ * coding, the process 0 metadata cache is forbidden to flush entries outside
+ * of a sync point.
+ *
+ * However, for different metadata write strategies, these fields are used
+ * only to maintain the correct dirty byte count on process zero -- and in
+ * most if not all cases, this is redundant, as process zero will be barred
+ * from flushing entries outside of a sync point.
+ *
+ *						JRM -- 3/16/10
+ *
  * d_slist_ptr:  Pointer to an instance of H5SL_t used to maintain a list
  *		of entries that have been dirtied since the last time they
  *		were listed in a clean entries broadcast.  This list is
@@ -259,6 +292,17 @@
  *		contain the value 0 on all processes other than process 0.
  *		It exists primarily for sanity checking.
  *
+ * The following two fields are used only when metadata_write_strategy
+ * is H5AC_METADATA_WRITE_STRATEGY__DISTRIBUTED.
+ *
+ * candidate_slist_ptr: Pointer to an instance of H5SL_t used by process 0
+ *		to construct a list of entries to be flushed at this sync
+ *		point.  This list is then broadcast to the other processes,
+ *		which then either flush or mark clean all entries on it.
+ *
+ * candidate_slist_len: Integer field containing the number of entries on the
+ *		candidate list.  It exists primarily for sanity checking.
+ *
  * write_done:  In the parallel test bed, it is necessary to ensure that
  *              all writes to the server process from cache 0 complete
  *              before it enters the barrier call with the other caches.
@@ -271,6 +315,19 @@
  *              This field must be set to NULL when the callback is not
  *              needed.
  *
+ *		Note: This field has been extended for use by all processes
+ *		      with the addition of support for the distributed 
+ *		      metadata write strategy.        
+ *                                                     JRM -- 5/9/10
+ *
+ * sync_point_done:  In the parallel test bed, it is necessary to verify
+ *		that the expected writes, and only the expected writes,
+ *		have taken place at the end of each sync point.
+ *
+ *		The sync_point_done callback allows t_cache to perform 
+ *		this verification.  The field is set to NULL when the 
+ *		callback is not needed.
+ *
  ****************************************************************************/
 
 #ifdef H5_HAVE_PARALLEL
@@ -293,6 +350,8 @@ typedef struct H5AC_aux_t
 
     int32_t	dirty_bytes;
 
+    int32_t	metadata_write_strategy;
+
 #if H5AC_DEBUG_DIRTY_BYTES_CREATION
 
     int32_t	dirty_bytes_propagations;
@@ -316,8 +375,15 @@ typedef struct H5AC_aux_t
 
     int32_t	c_slist_len;
 
+    H5SL_t *	candidate_slist_ptr;
+
+    int32_t	candidate_slist_len;
+
     void	(* write_done)(void);
 
+    void	(* sync_point_done)(int num_writes, 
+                                    haddr_t * written_entries_tbl);
+
 } H5AC_aux_t; /* struct H5AC_aux_t */
 
 #endif /* H5_HAVE_PARALLEL */