What is the state of the G1 Garbage Collector?

Because I do not know what is the current state of the Java G1 Garbage Collector, I decided to try G1 with JDK6u20. Somehow I was disappointed because after a short moment of predictable GC performance, the entire VM stopped and some major collection was running. You can easily see that in the charts of that run. Right around 20:09:45, the threads were stopped and the entire VM behaved ugly.

The G1 stop the world

So, the G1 is not yet ready for production, of course nobody stated that it is ready for production. If I read the release notes of JDK6u21 correctly, it delivers plenty of G1 changes, so I might try that soon.