AW: AW: Minor GCs grow longer after Full GC

[Andreas Müller]

Hi Thomas,

>Please report back any experience. This helps us a lot to further improve G1. Preferably, if there are issues, with a log :)
We had an issue in our Tomcat configuration which caused the problem in the end (see below), but G1 suffered more from that problem than other collectors in Java 7-72.
I'll send you the detailed GC log in separate mail because it is too large for the mailing list.

>> > Yes, but it seems that in your case the perm gen (or one of those additional roots) seems to be the problem.
>> Good hint, but from what do you conclude that?
>From that your application is a tomcat application server, the huge perm gen in conjunction with your comments about perm gen, and some guessing :)
>We have worked together with people on another application server where the same behavior has been seen, and we found that there has been a similar problem with code roots and class unloading.
We have now identified and fixed the root problem:
- yes, growing minor GC times were related to a growing perm heap occupation
- perm heap occupation grew because JSPs were recompiled and regenerated servlet classes reloaded (cause: maxLoadedJsps was set to some value in the web.xml and exceeded over and over again)

Regards and thanks
Andreas