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https://issues.apache.org/jira/browse/HADOOP-10778?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14054057#comment-14054057
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Tsz Wo Nicholas Sze commented on HADOOP-10778:
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> ... For example, if a GC hits when we're doing the benchmark, or another
> process uses a bunch of CPu, we might choose the wrong implementation. ...
Benchmark is reliable only if it is run for many times and the results are
consistent. It is not like the we run it one time and use the result to change
the code.
> As you guys know, most of our users on x86 just use CRC32C (not CRC32) ...
This JIRA has nothing to do with CRC32C.
> Use NativeCrc32 only if it is faster
> ------------------------------------
>
> Key: HADOOP-10778
> URL: https://issues.apache.org/jira/browse/HADOOP-10778
> Project: Hadoop Common
> Issue Type: Improvement
> Components: util
> Reporter: Tsz Wo Nicholas Sze
> Assignee: Tsz Wo Nicholas Sze
> Attachments: c10778_20140702.patch
>
>
> From the benchmark post in [this
> comment|https://issues.apache.org/jira/browse/HDFS-6560?focusedCommentId=14044060&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14044060],
> NativeCrc32 is slower than java.util.zip.CRC32 for Java 7 and above when
> bytesPerChecksum > 512.
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