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From "Mikhail Fursov" <mike.fur...@gmail.com>
Subject Re: [classlib][performance] performance improvement for luni and nio_char modules - Harmony-1980
Date Fri, 27 Oct 2006 06:06:48 GMT
Vladimir,
I see you removed some arraycopy operations in your patch as not effective.
I'm Ok with your solution but what to know if JIT could solve the problem
generating more effective code? Do you have any suggestions for JIT here?

On 10/27/06, Geir Magnusson Jr. <geir@pobox.com> wrote:
>
> 10%-15%?  That's amazing.  How fast are we (DRLVM) compared to Sun 1.5
> using decapo?
>
> geir
>
>
> Vladimir Strigun wrote:
> > 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) <jira@apache.org> 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
> >>
> >>
> >> --
> >> This message is automatically generated by JIRA.
> >> -
> >> If you think it was sent incorrectly contact one of the
> >> administrators:
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> >> -
> >> For more information on JIRA, see:
> http://www.atlassian.com/software/jira
> >>
> >>
> >>
> >
>



-- 
Mikhail Fursov

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