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Posted to common-issues@hadoop.apache.org by "Allen Wittenauer (JIRA)" <ji...@apache.org> on 2010/02/25 00:01:29 UTC
[jira] Commented: (HADOOP-6133) ReflectionUtils performance
regression
[ https://issues.apache.org/jira/browse/HADOOP-6133?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12838062#action_12838062 ]
Allen Wittenauer commented on HADOOP-6133:
------------------------------------------
Anyone know off hand what branch this was committed to and can set the 'fix version' field?
> ReflectionUtils performance regression
> --------------------------------------
>
> Key: HADOOP-6133
> URL: https://issues.apache.org/jira/browse/HADOOP-6133
> Project: Hadoop Common
> Issue Type: Improvement
> Components: conf
> Affects Versions: 0.20.0
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Attachments: hadoop-6133-0.20.patch, hadoop-6133-trunk.txt, hadoop-6133-trunk.txt, Test.java
>
>
> HADOOP-4187 introduced extra calls to Class.forName in ReflectionUtils.setConf. This caused a fairly large performance regression. Attached is a microbenchmark that shows the following timings (ms) for 100M constructions of new instances:
> Explicit construction (new Test): around ~1.6sec
> Using Test.class.newInstance: around ~2.6sec
> ReflectionUtils on 0.18.3: ~8.0sec
> ReflectionUtils on 0.20.0: ~200sec
> This illustrates the ~80x slowdown caused by HADOOP-4187.
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