[RFC] Adding dtrace probe points for more detailed GC information

[Sunny Chan]

Lukas Berk <lberk at ...> writes:
 
> At this point I've identified collect() functions to probe, and keeping
> in mind scavenges as a TODO.  Are there any other key processes within
> garbage collection that I should be aware of or take into consideration?
> The patch (based off of icedtea7 tip) is attached, and any comments are
> appreciated.

Hi Lukas,
 
Just some initial thoughts:
 
Finailization/Soft reference processing
CMS concurrent state stats (see 
CMSCollector::collect_in_background/collect_in_foreground)
Perm Gen collection start and stop
 
Also, it would be useful to have GC cause logged (e.g. in your 
psParallelCompact.cpp, gc cause is not traced).
 
Ideally, statistics/event available in verbose:gc output should make it to 
dtrace - maybe when they have implemented JEP 158 
(http://openjdk.java.net/jeps/158), you should add dtrace points into the 
logging framework.

Thanks.