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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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Joshua McKenzie updated CASSANDRA-13903:
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Labels: Performance (was: )
> 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
> Priority: Major
> Labels: Performance
>
> 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. Feature details please refer to
> http://download.java.net/java/jdk9/docs/api/java/util/Arrays.html and
> https://bugs.openjdk.java.net/browse/JDK-8033148
> 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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