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https://issues.apache.org/jira/browse/HBASE-22134?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16805633#comment-16805633
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Todd Lipcon commented on HBASE-22134:
-------------------------------------
Looks a lot like what's reported here:
http://openjdk.5641.n7.nabble.com/Deoptimization-taking-up-most-CPU-cycles-td274012.html
> JIT deoptimization in Cell.write
> --------------------------------
>
> Key: HBASE-22134
> URL: https://issues.apache.org/jira/browse/HBASE-22134
> Project: HBase
> Issue Type: Bug
> Components: Performance
> Affects Versions: 2.0.2
> Reporter: Todd Lipcon
> Priority: Major
>
> I was looking at a profile of a workload which was running compaction very
> slowly, and saw that the top CPU consumers were from JVM internals regarding
> deoptimization. I managed to write a little systemtap script to extract the
> deoptimization log and got the following in a tight loop:
> "Uncommon trap: trap_request=0xffffff67 fr.pc=0x00007f85bcdb8644"
> "Uncommon trap: reason=unstable_if action=none pc=0x00007f85bcdb8644
> method=org.apache.hadoop.hbase.io.encoding.NoneEncoder.write(Lorg/apache/hadoop/hbase/Cell;)I
> @ 67"
> "DEOPT PACKING pc=0x00007f85bcdb8644 sp=0x00007f84d3d83080"
> "DEOPT UNPACKING pc=0x00007f85b5005229 sp=0x00007f84d3d82f30 mode 2"
> The java stack is spending most of its time at:
> java.lang.Thread.State: RUNNABLE
> at
> org.apache.hadoop.hbase.io.encoding.NoneEncoder.write(NoneEncoder.java:57)
> at
> org.apache.hadoop.hbase.io.hfile.NoOpDataBlockEncoder.encode(NoOpDataBlockEncoder.java:55)
> at
> org.apache.hadoop.hbase.io.hfile.HFileBlock$Writer.write(HFileBlock.java:983)
> at
> org.apache.hadoop.hbase.io.hfile.HFileWriterImpl.append(HFileWriterImpl.java:740)
> This was with Oracle JDK 1.8.0_112. Likely a JDK bug but perhaps some
> reorganization of this code path could help avoid triggering the bug.
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