I'm the author of this post. Note that it's entirely adapted from the talk done by Attila Szegedi (http://www.infoq.com/presentations/JVM-Performance-Tuning-tw...), who deserves all the credit. I just filled in some of the gaps and reworked it so it flows in textual form.

I'll try to update the post with any comments I get here. It's definitely not ground truth as I was a bit fuzzy on some parts of the presentation.