[svn-r6252] Purpose:

    Lots of performance improvements & a couple new internal API interfaces.

Description:
    Performance Improvements:
        - Cached file offset & length sizes in shared file struct, to avoid
            constantly looking them up in the FCPL.
        - Generic property improvements:
            - Added "revision" number to generic property classes to speed
                up comparisons.
            - Changed method of storing properties from using a hash-table
                to the TBBT routines in the library.
            - Share the propery names between classes and the lists derived
                from them.
            - Removed redundant 'def_value' buffer from each property.
            - Switching code to use a "copy on write" strategy for
                properties in each list, where the properties in each list
                are shared with the properties in the class, until a
                property's value is changed in a list.
        - Fixed error in layout code which was allocating too many buffers.
        - Redefined public macros of the form (H5open()/H5check, <variable>)
            internally to only be (<variable>), avoiding innumerable useless
            calls to H5open() and H5check_version().
        - Reuse already zeroed buffers in H5F_contig_fill instead of
            constantly re-zeroing them.
        - Don't write fill values if writing entire dataset.
        - Use gettimeofday() system call instead of time() system when
            checking the modification time of a dataset.
        - Added reference counted string API and use it for tracking the
            names of objects opening in a file (for the ID->name code).
        - Removed redundant H5P_get() calls in B-tree routines.
        - Redefine H5T datatype macros internally to the library, to avoid
            calling H5check redundantly.
        - Keep dataspace information for dataset locally instead of reading
            from disk each time.  Added new module to track open objects
            in a file, to allow this (which will be useful eventually for
            some FPH5 metadata caching issues).
        - Remove H5AC_find macro which was inlining metadata cache lookups,
            and call function instead.
        - Remove redundant memset() calls from H5G_namei() routine.
        - Remove redundant checking of object type when locating objects
            in metadata cache and rely on the address only.
        - Create default dataset object to use when default dataset creation
            property list is used to create datasets, bypassing querying
            for all the property list values.
        - Use default I/O vector size when performing raw data with the
            default dataset transfer property list, instead of querying for
            I/O vector size.
        - Remove H5P_DEFAULT internally to the library, replacing it with
            more specific default property list based on the type of
            property list needed.
        - Remove redundant memset() calls in object header message (H5O*)
            routines.
        - Remove redunant memset() calls in data I/O routines.
        - Split free-list allocation routines into malloc() and calloc()-
            like routines, instead of one combined routine.
        - Remove lots of indirection in H5O*() routines.
        - Simplify metadata cache entry comparison routine (used when
            flushing entire cache out).
        - Only enable metadata cache statistics when H5AC_DEBUG is turned
            on, instead of always tracking them.
        - Simplify address comparison macro (H5F_addr_eq).
        - Remove redundant metadata cache entry protections during dataset
            creation by protecting the object header once and making all
            the modifications necessary for the dataset creation before
            unprotecting it.
        - Reduce # of "number of element in extent" computations performed
            by computing and storing the value during dataspace creation.
        - Simplify checking for group location's file information, when file
            has not been involving in file-mounting operations.
        - Use binary encoding for modification time, instead of ASCII.
        - Hoist H5HL_peek calls (to get information in a local heap)
            out of loops in many group routine.
        - Use static variable for iterators of selections, instead of
            dynamically allocation them each time.
        - Lookup & insert new entries in one step, avoiding traversing
            group's B-tree twice.
        - Fixed memory leak in H5Gget_objname_idx() routine (tangential to
            performance improvements, but fixed along the way).
        - Use free-list for reference counted strings.
        - Don't bother copying object names into cached group entries,
            since they are re-created when an object is opened.

        The benchmark I used to measure these results created several thousand
        small (2K) datasets in a file and wrote out the data for them.  This is
        Elena's "regular.c" benchmark.

        These changes resulted in approximately ~4.3x speedup of the
        development branch when compared to the previous code in the
        development branch and ~1.4x speedup compared to the release
        branch.

        Additionally, these changes reduce the total memory used (code and
        data) by the development branch by ~800KB, bringing the development
        branch back into the same ballpark as the release branch.

        I'll send out a more detailed description of the benchmark results
        as a followup note.

    New internal API routines:
        Added "reference counted strings" API for tracking strings that get
            used by multiple owners without duplicating the strings.
        Added "ternary search tree" API for text->object mappings.

Platforms tested:
    Tested h5committest {arabica (fortran), eirene (fortran, C++)
	modi4 (parallel, fortran)}
    Other platforms/configurations tested?
        FreeBSD 4.7 (sleipnir) serial & parallel
        Solaris 2.6 (baldric) serial

1 files changed, 16 insertions, 10 deletions

diff --git a/src/H5Gent.c b/src/H5Gent.c
index 4e0a4f9..3bf1a58 100644
--- a/src/H5Gent.c
+++ b/src/H5Gent.c
@@ -357,6 +357,9 @@ done:
  *              of the functions in the library.
  *          - Added 'depth' parameter to determine how much of the group
  *              entry structure we want to copy.  The new depths are:
+ *                  H5G_COPY_NULL - Copy all the fields from the
+ *                      source to the destination, but set the destination's
+ *                      user path and canonical path to NULL.
  *                  H5G_COPY_LIMITED - Copy all the fields from the
  *                      source to the destination, except for the user path
  *                      field, keeping it the same as its
@@ -373,19 +376,19 @@ done:
 herr_t
 H5G_ent_copy(H5G_entry_t *dst, const H5G_entry_t *src, H5G_ent_copy_depth_t depth)
 {
-    char *tmp_user_path=NULL;   /* Temporary string pointers for entry's user path */
+    H5RS_str_t *tmp_user_path_r=NULL;   /* Temporary string pointer for entry's user path */
     herr_t ret_value=SUCCEED;   /* Return value */
 
     FUNC_ENTER_NOAPI(H5G_ent_copy, FAIL);
 
-    /* check arguments */
-    assert( src );
-    assert( dst );
+    /* Check arguments */
+    assert(src);
+    assert(dst);
 
     /* If the depth is "very shallow", keep the old entry's user path */
     if(depth==H5G_COPY_LIMITED) {
-        tmp_user_path=dst->user_path;
-        H5MM_xfree(dst->canon_path);
+        tmp_user_path_r=dst->user_path_r;
+        H5RS_decr(dst->canon_path_r);
     } /* end if */
 
     /* Copy the top level information */
@@ -393,11 +396,14 @@ H5G_ent_copy(H5G_entry_t *dst, const H5G_entry_t *src, H5G_ent_copy_depth_t dept
 
     /* Deep copy the names */
     if(depth==H5G_COPY_DEEP) {
-        dst->user_path=H5MM_xstrdup(src->user_path);
-        dst->canon_path=H5MM_xstrdup(src->canon_path);
+        dst->user_path_r=H5RS_dup(src->user_path_r);
+        dst->canon_path_r=H5RS_dup(src->canon_path_r);
     } else if(depth==H5G_COPY_LIMITED) {
-        dst->user_path=tmp_user_path;
-        dst->canon_path=H5MM_xstrdup(src->canon_path);
+        dst->user_path_r=tmp_user_path_r;
+        dst->canon_path_r=H5RS_dup(src->canon_path_r);
+    } else if(depth==H5G_COPY_NULL) {
+        dst->user_path_r=NULL;
+        dst->canon_path_r=NULL;
     } /* end if */
 
 done: