verbosegc

Definition of Java's CMS GC log lines?

Examining a Java runtime with CMS (Concurrent-Mark-Sweep) GC enabled, what is the definition of the CMS space in the logs below? Shall I assume it is the tenured space? I see the following lines of a minor-major-minor GC event 23.481: [GC 23.481: [DefNew: 1051K->128K(1152K), 0.0029912 secs] 11925K->11027K(13600K), 0.0031697 secs] [Tim...

Definition of Java's mark-preclean-sweep-reset GC lines?

Can someone please provide some insight into the the following verbosegc lines on a Java runtime with CMS GC enabled? Specifically: Does the event at 29.490 indicate heap location of the highwater for marking? What is the preclean phase and what is it doing different than marking? What is the reset phase? Why would that take time to...