APAR status
Closed as program error.
Error description
Error Message: The symptoms of this APAR are sustained high CPU usage by a JIT compilation thread, and potentially the JVM hanging on shutdown. Additionally, a JIT verbose log will show a compile request for a method that never completes even after a long period of time, or takes far too long to complete. . Stack Trace: The stack backtrace of the JIT compiler thread using sustained high CPU may look like this: fixUpTree() // likely many frames of this TR_EliminateDeadTrees::process() .
Local fix
This problem can be avoided using the Java command line option -Xjit:disableDeadTreeElimination Note that this may affect performance. This can be limited by only applying the option to the method(s) experiencing the problem.
Problem summary
Certain patterns of Java bytecodes can cause the JIT optimization Dead Tree Elimination to get stuck iterating over the same trees in an exponential walk, causing the optimization and compilation to run for a very long time and give the appearance of being stuck in an infinite loop. This causes the JIT compilation thread compiling the method to sustain high CPU usage and potentially prevent JVM shutdown.
Problem conclusion
Checks have been added to the Dead Tree Elimination optimization to prevent the JIT compiler from getting stuck iterating over the same trees in an exponential walk. . This APAR will be fixed in the following Java Releases: 7 R1 SR4 FP20 (7.1.4.20) 7 SR10 FP20 (7.0.10.20) 6 R1 SR8 FP60 (6.1.8.60) 8 SR5 FP6 (8.0.5.6) . Contact your IBM Product's Service Team for these Service Refreshes and Fix Packs. For those running stand-alone, information about the available Service Refreshes and Fix Packs can be found at: https://www.ibm.com/developerworks/java/jdk/
Temporary fix
Comments
APAR Information
APAR number
IV88941
Reported component name
JIT
Reported component ID
620700124
Reported release
130
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2016-09-02
Closed date
2017-11-15
Last modified date
2017-11-15
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
JIT
Fixed component ID
620700124
Applicable component levels
R130 PSY
UP
R260 PSY
UP
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Document Information
Modified date:
15 November 2017