shylaja kokoori created CASSANDRA-12787:
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Summary: Reduce instanceOf() type checking to improve performance
Key: CASSANDRA-12787
URL: https://issues.apache.org/jira/browse/CASSANDRA-12787
Project: Cassandra
Issue Type: Improvement
Environment: The tests and examples stated were run on:
Intel (R) Xeon (R) CPU E5-2699 v3 @ 2.30GHz, HT Enabled
Oracle JDK 1.8
Cassandra 3.10-SNAPSHOT
Linux kernel 4.7
Reporter: shylaja kokoori
Fix For: 3.x
Attachments: reduce_instanceof_typechecking.pdf
While performance profiling Cassandra with cassandra-stress test on a pure
write workload, we noticed that one of the hot methods for Cassandra server is
the compareTo( PartitionPosition pos) function in
org.apache.cassandra.db.DecoratedKey. The actual root cause of the problem is a
slowdown in Java's instanceof operator.
Our initial performance testing using a hacked JVM shows about 61% increase in
throughput and about 15% reduction in 99 percentile latency. Data shows that
improvements are from the removal of thread contention caused by Instanceof
operator.
Currently, we are working on a JDK fix to solve this issue. In the meantime, we
think it will be beneficial to address this issue at Java application level as
well. We are in the process of creating a patch to Cassandra replacing
instanceof check with virtual method calls. The patch will be available in this
thread for review soon. Please let us know your feedback and comments.
For more details please refer to the attached pdf.
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