I stumbled across GChisto the other day when looking for some garbage collection analysis tools for Java. Anyone who's tried tuning Java GC (especially on older JVM's) knows that it's about as much fun as watching paint dry. However, many times you can seriously improve performance by taking the time to analyze what your GC's are doing. GChisto attempts to give you a birds-eye graphical view of your GC operations, and has a very handy comparison feature that allows you to compare the differences between GC logs.