diff options
| author | Quincey Koziol <koziol@hdfgroup.org> | 2003-05-07 21:52:24 (GMT) |
|---|---|---|
| committer | Quincey Koziol <koziol@hdfgroup.org> | 2003-05-07 21:52:24 (GMT) |
| commit | 43e3b450214310728cbb6904211319a8459f06e4 (patch) | |
| tree | 13cc61b9f713aa60fdcaf606665f03189689046d /release_docs | |
| parent | db543f1a23194e81d0a984c346398e72bf4be87f (diff) | |
| download | hdf5-43e3b450214310728cbb6904211319a8459f06e4.zip hdf5-43e3b450214310728cbb6904211319a8459f06e4.tar.gz hdf5-43e3b450214310728cbb6904211319a8459f06e4.tar.bz2 | |
[svn-r6825] Purpose:
New feature/enhancement
Description:
Chunked datasets are handled poorly in several circumstances involving
certain selections and chunks that are too large for the chunk cache and/or
chunks with filters, causing the chunk to be read from disk multiple times.
Solution:
Rearrange raw data I/O infrastructure to handle chunked datasets in a much
more friendly way by creating a selection in memory and on disk for each chunk
in a chunked dataset and performing all of the I/O on that chunk at one time.
There are still some scalability (the current code attempts to
create a selection for all the chunks in the dataset, instead of just the
chunks that are accessed, requiring portions of the istore.c and fillval.c
tests to be commented out) and performance issues, but checking this in will
allow the changes to be tested by a much wider audience while I address the
remaining issues.
Platforms tested:
h5committested, FreeBSD 4.8 (sleipnir) serial & parallel, Linux 2.4 (eirene)
Diffstat (limited to 'release_docs')
| -rw-r--r-- | release_docs/RELEASE.txt | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt index 48d8b27..fe64554 100644 --- a/release_docs/RELEASE.txt +++ b/release_docs/RELEASE.txt @@ -283,6 +283,11 @@ Documentation New Features ============ + * Changed raw data I/O to only access each chunk once, improving performance + in many situations with hyperslabs and large chunks or chunks with + filters. These improvements are currently limited to serial I/O, with + similar parallel I/O improvements forthcoming sometime in the future. + QAK - 2003/05/07 * Added parameter to the MPI/POSIX driver. If GPFS is enabled (by modifying the H5FDmpiposix.c file to uncomment the USE_GPFS_HINTS macro), then this extra parameter will turn GPFS hints on and off |