"abort preclean due to time" in Concurrent Mark & Sweep

I'm getting "abort preclean due to time" when running Concurrent Mark & Sweep in Java 6开发者_开发技巧. What does it mean? Is the GC really halting in the middle before it did any real work?

Check out the section MaxAbortablePrecleanTime in Masamitsu's blog. This will give you a better idea about what the preclean phase is doing. Better than i'm willing to type out ;)