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https://issues.apache.org/jira/browse/CASSANDRA-13903?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Yingqi Lu updated CASSANDRA-13903:
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    Labels:   (was: Cassandra-9608 dependency)

> Add JDK9 vectorizedMismatch array compare support
> -------------------------------------------------
>
>                 Key: CASSANDRA-13903
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-13903
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Local Write-Read Paths
>            Reporter: Yingqi Lu
>
> Dear All,
> JDK9 has recently been released (http://openjdk.java.net/projects/jdk9/). It 
> introduces a set of new vectorizedMismatch APIs for array comparison. On 
> supported platforms, the new JDK9 implementation is intrisified to leverage 
> SIMD instructions. For a byte array comparison, up to 64 bytes (512 bits) can 
> be compared as a single unit.  
> Currently in Cassandra, keys are implemented as ByteBuffers and compared as 
> byte arrays most of the time. Key comparison, for example decorated key 
> compare, it is either done with unsafe operation taking 8 bytes at a time, or 
> pure java operation comparing byte by byte. This can be optimized with new 
> JDK9 java.util.Arrays.compare APIs on modern CPUs.
> Please let us know your feedback. At the meantime, we will submit a patch 
> with performance studies in couple of weeks.
> Thanks,
> Yingqi Lu



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