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https://issues.apache.org/jira/browse/HADOOP-10674?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14028688#comment-14028688
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Tsz Wo Nicholas Sze commented on HADOOP-10674:
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In Java 7 and 8, the new code is faster than the existing code by 10% - 20% in 
most cases.  However, it is still slower than java.util.zip.CRC32.

[~rajesh.balamohan], thanks for check Java 7 and 8.  You may want to try again 
with the new patch.

[~gopalv], are you going to test the patch?

> Rewrite the PureJavaCrc32 loop for performance improvement
> ----------------------------------------------------------
>
>                 Key: HADOOP-10674
>                 URL: https://issues.apache.org/jira/browse/HADOOP-10674
>             Project: Hadoop Common
>          Issue Type: Improvement
>          Components: performance, util
>            Reporter: Tsz Wo Nicholas Sze
>            Assignee: Tsz Wo Nicholas Sze
>         Attachments: c10674_20140609.patch, c10674_20140609b.patch, 
> c10674_20140610.patch
>
>
> Below are some performance improvement opportunities performance improvement 
> in PureJavaCrc32.
> - eliminate "off += 8; len -= 8;"
> - replace T8_x_start with hard coded constants
> - eliminate c0 - c7 local variables
> In my machine, there are 30% to 50% improvement for most of the cases.



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