[svn-r8791] Purpose: Rewrote metadata cache (H5AC.c, etc.) to improve performance.

Description:

Replaced the old metadata cache with a cache with a modified LRU
replacement policy.  This should improve the hit rate.

Solution:

Since we want to flush cache entries in increasing address order, I
used the threaded binary B-tree code to store the cache entries.
There is a fair bit of overhead here, so we may want to consider
other options.

While the code is designed to allow the support of other replacement
algorithms, at present, only a modified version of LRU is supported.

The modified LRU algorithm requires that a user selectable portion
of the cache entries be clean.  The clean entries are evicted first
when writes are not permitted.  If the pool of clean entries is used
up, the cache grows beyond its user specified maximum size.  The
cache can also exceed its maximum size if the combined size of the
protected (or locked) entries exceeds the maximum size of the cache.


Platforms tested:

eirene (serial, parallel, fp), h5committested


Misc. update:

1 files changed, 39 insertions, 0 deletions

diff --git a/src/H5Gnode.c b/src/H5Gnode.c
index 7fc436c..530020e 100644
--- a/src/H5Gnode.c
+++ b/src/H5Gnode.c
@@ -72,6 +72,7 @@ static herr_t H5G_node_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t a
 			     H5G_node_t *sym);
 static herr_t H5G_node_dest(H5F_t *f, H5G_node_t *sym);
 static herr_t H5G_node_clear(H5F_t *f, H5G_node_t *sym, hbool_t destroy);
+static herr_t H5G_compute_size(H5F_t *f, H5G_node_t *sym, size_t *size_ptr);
 
 /* B-tree callbacks */
 static size_t H5G_node_sizeof_rkey(H5F_t *f, const void *_udata);
@@ -107,6 +108,7 @@ const H5AC_class_t H5AC_SNODE[1] = {{
     (H5AC_flush_func_t)H5G_node_flush,
     (H5AC_dest_func_t)H5G_node_dest,
     (H5AC_clear_func_t)H5G_node_clear,
+    (H5AC_size_func_t)H5G_compute_size,
 }};
 
 /* H5G inherits B-tree like properties from H5B */
@@ -619,6 +621,43 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5G_compute_size
+ *
+ * Purpose:	Compute the size in bytes of the specified instance of
+ *		H5G_node_t on disk, and return it in *size_ptr.  On failure
+ *		the value of size_ptr is undefined.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	John Mainzer
+ *		5/13/04
+ *
+ * Modifications:
+ * 
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5G_compute_size(H5F_t *f, H5G_node_t UNUSED *sym, size_t *size_ptr)
+{
+    herr_t      ret_value=SUCCEED;       /* Return value */
+
+    FUNC_ENTER_NOAPI(H5G_compute_size, FAIL);
+
+    /*
+     * Check arguments.
+     */
+    assert(f);
+    assert(size_ptr);
+
+    *size_ptr = H5G_node_size(f);
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value);
+
+} /* H5G_compute_size() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5G_node_create
  *
  * Purpose:	Creates a new empty symbol table node.	This function is