Debugging G1 GC
I wonder if anyone can suggest to me how I can go about debugging G1 GC.
We are seeing this happening:
After moving from CMS to G1, my application will suddenly uses up 60-70% of a CPU Core for no good reason. Although this is similar to a supposedly fixed bug (http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6870843), I didnt notice memory use kept going up. On the other hand I cannot help but seeing the similarity in terms of high CPU usage.
I cannot predict the time when the issue will happen but I know that if the problem occurs and I force a Full GC (or connect visualVM to it), the Core CPU utilization goes down rightaway.
I am using 1.6u18 b05. The flags I use are:
-XX:+G1ParallelRSetUpdatingEnabled <<< i have tried with or without this
-XX:+G1ParallelRSetScanningEnabled <<< i have tried with or without this
Any suggestion how can I log my observation for Java Bug reporting? visualVM does not seem to register G1's activities.