The optimization covers the following issues:
- java.nio.charset.CharsetDecoder and java.nio.charset.CharsetEncoder
Streaming decoding/encoding was removed. Analysis of API hotspots for
Dacapo shows that CharsetDecoder is frequently used almost in all
benchmark, especially in chart. We already discussed advantages of
streaming decoding but the fix shows significant performance
improvement on average for all Dacapo benchmarks. For instance, boost
for chart benchmark is about 16%. Paulex, you recently worked in
nio_char module and if I correctly remember you introduce streaming
operations, so could you please review the changes and let me know?
Since streaming operation was removed, tests have been slightly
modified as well (previous version of tests fails on RI).
- java.io.BufferedReader
readLine() method was slightly modified. Additional check whether some
characters available in cached buffer was added prior to main cycle.
- java.io.InputStreamReader
Cached char buffer was removed, read() , read(char[], int, int)
methods were rewritten. Current implementation of read(char[], int,
int) uses several invocation of System.arraycopy. Proposed solution
wraps char[] arguments within char buffer and therefore doesn't use
arraycopy. Decoding operation is also produced inside the method, so
fillBuf() has been removed
Thoughts? Comments?
Thanks,
Vladimir.
On 10/26/06, Vladimir Strigun (JIRA) <[EMAIL PROTECTED]> wrote:
[classlib][performance] performance improvement for luni and nio_char modules
-----------------------------------------------------------------------------
Key: HARMONY-1980
URL: http://issues.apache.org/jira/browse/HARMONY-1980
Project: Harmony
Issue Type: Improvement
Components: Classlib
Reporter: Vladimir Strigun
Attachments: Harmony-1980.diff
I've analyzed API frequently used in all Dacapo[1] benchmarks and found several
places in luni and nio_char modules that can be improved. Suggested fix gives
about 10-15% boost on average for Dacapo executed on DRLVM. I'll post more
details to dev list.
Attached fix contains modifications for the following classes:
java.io.BufferedReader, java.io.InputStreamReader,
java.nio.charset.CharsetDecoder and java.nio.charset.CharsetEncoder.
Please have a look to the results of Dacapo execution (values are in millisec,
so the less the better):
Small workload
OrigBuild Patched
bloat 996,078 1024,85
chart 1240,777 1068,112
fop 250,433 232,957
hsqldb 348,942 361,139
jython 831,143 824,775
lusearch 1854,95 1870,969
luindex 339,45 231,314
pmd 29,704 23,638
default workload
OrigBuild Patched
bloat 168733,562 175493,467
chart 31651,792 25681,751
fop 2546,289 2512,045
hsqldb 22873,608 13555,515
jython 128207,303 92863,28
lusearch 29425,991 30064,153
luindex 17825,795 18083,898
pmd 44548,724 40225,694
[1] http://dacapobench.sourceforge.net
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