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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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Description:
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
was:
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
> 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. 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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