[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, 66 insertions, 0 deletions

diff --git a/test/gen_old_mtime.c b/test/gen_old_mtime.c
new file mode 100644
index 0000000..b9a8186
--- /dev/null
+++ b/test/gen_old_mtime.c
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2003 NCSA
+ *                    All rights reserved.
+ *
+ * Programmer:  Quincey Koziol <koziol@ncsa.uiuc.edu>
+ *              Friday, January  3, 2003
+ *
+ * Purpose:	Create a dataset, which should have the older mtime information
+ *      stored in it.
+ *		This program is used to create the test file `tmtimeo.h5' which
+ *      has the new format for mtime information.
+ *		To build the test file, this program MUST be compiled and linked with
+ *      the hdf5-1.4+ series of libraries and the generated test file must be
+ *      put into the 'test' directory in the 1.5+ branch of the library.
+ */
+
+#include "hdf5.h"
+
+#define TESTFILE   "tmtimeo.h5"
+
+
+/*-------------------------------------------------------------------------
+ * Function:	main
+ *
+ * Purpose:	
+ *
+ * Return:	Success:	
+ *
+ *		Failure:	
+ *
+ * Programmer:	Quincey Koziol
+ *              Friday, January  3, 2003
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+main(void)
+{
+    hid_t	file, space, dset;
+
+    /* Create the file */
+    file = H5Fcreate(TESTFILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+    if(file<0)
+        printf("file<0!\n");
+
+    /* Create the dataspace (for dataset) */
+    space = H5Screate(H5S_SCALAR);
+    if(space<0)
+        printf("space<0!\n");
+
+    /* Create the dataset with compound array fields */
+    dset = H5Dcreate(file, "Dataset1", H5T_NATIVE_INT, space, H5P_DEFAULT);
+    if(dset<0)
+        printf("dset<0!\n");
+
+    H5Dclose(dset);
+    H5Sclose(space);
+    H5Fclose(file);
+
+    return 0;
+}
+
+
+