[svn-r22012] Purpose:

  Task for HDFFV-7862 - Select data by chunk direction to improve performance in h5repack

Description:
  h5repack sometimes became very slow when handling big chunked datasets in
  certain cases. (when chunk boundary doesn't match with a hyperslab boundary.)
  The main issue was from figuring out a hypeslab without considering chunk
  boundary to read from and write to such datasets.
  The update was made to figure out a better hyperslab unit with considering
  chunk boundary to improve performance for such cases prior to the update.


Tested:
  jam (linux32-LE), koala (linux64-LE), ostrich (linuxppc64-BE), tejeda (mac32-LE), linew (solaris-BE), Windows

1 files changed, 6 insertions, 0 deletions

diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index b9b28d1..b4c09f5 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -241,6 +241,12 @@ New Features
 
     Tools:
     ------
+     - h5repack: Improved performance for hanlding big chunked dataset 
+               (size > 128MB). It would perform much better prior to the
+               improvement, especially for cases that chunk dimentions
+               looks like "1024x5x1" (compare to "1x5x1024"). When bigger numbers
+               are toward front and smaller number is toward back in chunk
+               dimentions.
      - h5dump: Added new option --no-compact-subset. This option will not
                interpret the '[' character as starting the compact form of 
                subsetting. This is useful when the "h5dump error: unable to