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https://issues.apache.org/jira/browse/HADOOP-10674?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14029763#comment-14029763
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Gopal V commented on HADOOP-10674:
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[~szetszwo]: I will run the same with JDK7 and JDK8 with the j.u.zip.CRC32.

I am hoping that the native version doesn't have JNI critical sections. 

If it does have critical sections there as well, then we might as well use the 
new impl for those JDKs as well.

> 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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