diff options
| author | Quincey Koziol <koziol@hdfgroup.org> | 2002-06-04 13:37:51 (GMT) |
|---|---|---|
| committer | Quincey Koziol <koziol@hdfgroup.org> | 2002-06-04 13:37:51 (GMT) |
| commit | ba26e8f2ad29dbefd3078b2f97b7a731ba39db1e (patch) | |
| tree | 5080a9a458d135c22a394c60f170ff3349121b8d /release_docs | |
| parent | 8ae371469a5441e54c5df3c6a3372bdf6a66fc6b (diff) | |
| download | hdf5-ba26e8f2ad29dbefd3078b2f97b7a731ba39db1e.zip hdf5-ba26e8f2ad29dbefd3078b2f97b7a731ba39db1e.tar.gz hdf5-ba26e8f2ad29dbefd3078b2f97b7a731ba39db1e.tar.bz2 | |
[svn-r5521] Purpose:
Code improvement
Description:
The metadata aggregation code in the library was not terribly smart about
extending contiguous regions of metadata in the file and would not extend
them as far as possible. This causes space in the file to be wasted, also.
Solution:
Be smarter about extending the space used in the file for metadata by
checking whether new metadata blocks allocated in the file are at the end
of the current metadata aggregation region and append them to the metadata
region if so. This has the nice side benefit of reducing the number of
bytes we waste in the file and reducing the size of the file by a small
amount in some cases.
This reduces the number of I/O operations which hit the disk for my test
program from 53 to 19 (i.e. from 393 to 19, overall).
Platforms tested:
Solaris 2.7 (arabica) w/FORTRAN and FreeBSD 4.5 (sleipnir) w/C++
Diffstat (limited to 'release_docs')
| -rw-r--r-- | release_docs/RELEASE.txt | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt index d3b126b..4a2bd3d 100644 --- a/release_docs/RELEASE.txt +++ b/release_docs/RELEASE.txt @@ -168,6 +168,9 @@ Documentation New Features ============ + * Improved internal metadata aggregation, which can reduce the number of + actual I/O calls made, improving performance. Additionally, this can + reduce the size of files produced. QAK - 2002/06/04 * Improved internal metadata caching, which can reduce the number of actual I/O calls made by a substantial amount, improving performance. QAK - 2002/06/03 |