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From "Vladimir Strigun (JIRA)" <j...@apache.org>
Subject [jira] Created: (HARMONY-630) Performance improvement for BufferedReader and LineNumberReader classes
Date Tue, 20 Jun 2006 19:21:38 GMT
Performance improvement for BufferedReader and LineNumberReader classes
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         Key: HARMONY-630
         URL: http://issues.apache.org/jira/browse/HARMONY-630
     Project: Harmony
        Type: Improvement

  Components: Classlib  
    Reporter: Vladimir Strigun
    Priority: Minor


Analysis of BufferedReader and LineNumberReader was made by our team. These classes are widely
used and it's recommended, for instance, that any character IO should go through BufferedReader
for better performance. Therefore it should perform well and should not itself be a bottleneck.


We have identified opportunity to increase performance of mentioned classes. Publicly available
bench DaCapo[1] was used for performance measurement and we found that DaCapo:hsqldb benchmark
performance can be improved within small modification of java.io.BufferedReader and java.io.LineNumberReader
classes. Main idea of the patch (I will attach it soon) is to remove StringBuilder allocation
from "malloc"-hot methods readLine. 

Here is result of DaCapo execution with patched and original versions of classlib+J9:
Build	Dacapo: fop	Dacapo: hsqldb	Dacapo: xalan	Dacapo: chart	
original	712.020	27232.647	4201.449	22573.192	
patched	715.152	26703.966	4161.018	22580.771	


[1] http://www-ali.cs.umass.edu/DaCapo/gcbm.html


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