Xiaoming Xiaoming - 1 month ago 36
Java Question

How can I read IBM jit dump file

I want to look into the jitdump.20160505.165247.149.0004.dmp file.

Which is generated by IBM JVM 1.8 when it's crashing. Does anyone know how to read the dmp file?

I tried to use jextract to analyze it, but it complaints as following:

/opt/ibm/ibm-java-x86_64-80/jre/bin/jextract /tmp/jitdump.20160505.165247.149.0004.dmp -v
Loading dump file...
Error. Dump type not recognised, file: /tmp/jitdump.20160505.165247.149.0004.dmp


When trying to open jitdump file via MAT+DTFJ, here is the error message:

Error opening heap dump 'jitdump.20160505.165247.149.0004.dmp'. Check the error log for further details.
Unable to read dump C:\Users\IBM_ADMIN\Desktop\core_files\opt\ibm\apm\playback\selenium\jitdump.20160505.165247.149.0004.dmp metafile null in DTFJ format DTFJ-J9 (java.io.IOException)
Unable to read dump C:\Users\IBM_ADMIN\Desktop\core_files\opt\ibm\apm\playback\selenium\jitdump.20160505.165247.149.0004.dmp metafile null in DTFJ format DTFJ-J9
No Image sources were found for C:\Users\IBM_ADMIN\Desktop\core_files\opt\ibm\apm\playback\selenium\jitdump.20160505.165247.149.0004.dmp (java.io.IOException)
No Image sources were found for C:\Users\IBM_ADMIN\Desktop\core_files\opt\ibm\apm\playback\selenium\jitdump.20160505.165247.149.0004.dmp

Answer

The file is intended for IBM internal analysis only, the contents of the JIT dump files are not useful to anyone without an in depth understanding of the IBM JDK's JIT compiler internals. The existence of JIT dump file(s) does not imply that a JIT problem was encountered, the file was generated to collect data during a JVM crash so that if the crash is determined to be a JIT problem that IBM would stand a better chance of fixing the problem without having to ask for more data by recreating the problem several times.