JVM options to get full visibility on generation behavior and GC log analysis tools.

Alex Aisinzon aaisinzon at guidewire.com
Thu Jun 19 18:30:33 UTC 2008



I spend much time analyzing the behavior of the various generations.
Their optimal sizing provides good performance improvements.


I have several questions:

*	I add the following parameters to get good GC logs:
"-XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintHeapAtGC
-XX:+PrintGCApplicationStoppedTime". I wonder if some additional options
are useful. By example, the timestamps only track time since the JVM was
started. To correlate an incident with application time stamps, it would
be much more useful to have those time stamps use regular dates
(2008-06-17 11:58:11,23 by example).
*	I have not found a good tool to analyze these logs and have to
do that analysis by hand. HPJTune (HP) and GCViewer (TagTraum) are
sometimes good enough but does not work when using more refined GC
options like Parallel New Garbage Collection.. PrintGCStats is a last
one that I have not found very useful either. Are there other tools
available that someone could recommend?


In comparison, the IBM JDK provides a single GC output format by using
the verbose:gc option. IBM provides some very good tools to analyze
those logs. 


Thanks in advance for helping tuning the Sun JDK as well as possible.


This is for Sun JDK 1.5.


Alex Aisinzon





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