Answering my own questions... I added this comment to http://platform.xwiki.org/xwiki/bin/view/AdminGuide/Performances
> NielsMayer | 19.02.2009 at 03:21 PM > From > <http://nielsmayer.com/xwiki/bin/view/fedora10/64bitJavaAppletIn64BitFirefox#Comments> > http://nielsmayer.com/xwiki/bin/view/fedora10/64bitJavaAppletIn64BitFirefox#Comments > > <http://nielsmayer.com/xwiki/bin/view/fedora10/64bitJavaAppletIn64BitFirefox#Comments> > > For info on 6u14's new "Garbage First" GC and potential usefulness for use > with java web apps, see: > <http://n2.nabble.com/Does-JDK6u14-%22Garbage-First-garbage-collector-%28G1%29%22-work-and-or-improve-Xwiki-performance-size-mem-locality--tp2344358p2344358.html> > http://n2.nabble.com/Does-JDK6u14-%22Garbage-First-garbage-collector-%28G1%29%22-work-and-or-improve-Xwiki-performance-size-mem-locality--tp2344358p2344358.htmlor > <http://n2.nabble.com/forum/PrintPost.jtp?post=2344358> > http://n2.nabble.com/forum/PrintPost.jtp?post=2344358 (cancel the print > dialog: this gives you the complete message w/o extra crap). > > Unfortunately, when running with > > VM Arguments: > jvm_args: -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -Xms256m -Xmx768m > -XX:PermSize=256m -XX:MaxPermSize=768m -Djava.awt.headless=true … > java_command: org.apache.catalina.startup.Bootstrap start > > You get a SIGSEGV (which obviates the whole point of garbage-collection): > > A fatal error has been detected by the Java Runtime Environment: > SIGSEGV (0xb) at pc=0x0000000000e9c621, pid=13441, tid=114968912 > JRE version: 6.0_14-b01 > Java VM: OpenJDK 64-Bit Server VM (14.0-b10 mixed mode linux-amd64 ) > Problematic frame: > V [libjvm.so+0x296621] > > The SIGSEGV happens because of new Garbage Collector, as invoked by > "-XX:+UnlockExperimentalVMOptions -XX:+UseG1GC". It dies after running for > less than an hour: > > Current thread (0x000000004149f000): ConcurrentGCThread [stack: > 0x0000000000000000,0x0000000000000000] [id=13448] > siginfo:si_signo=SIGSEGV: si_errno=0, si_code=1 (SEGV_MAPERR), > si_addr=0x0000001600000050 > … > elapsed time: 2916 seconds > > This issue doesn't occur with the default GC invoked with > > jvm_args: -Xms256m -Xmx768m -XX:PermSize=256m -XX:MaxPermSize=768m > -Djava.awt.headless=true" > > I guess that's why this is an "Early Access" release. > -------------------------- also from my previous message re: > PS: and will a different GC prevent sequences like this from happening?? > see http://nielsmayer.com/happy-happy-joy-joy.txt This is solved by adding -XX:PermSize=256m -XX:MaxPermSize=768m although these values are probably far larger than necessary. This might be an issue that tomcat affects tomcat users in particular: Preventing Java's java.lang.OutOfMemoryError: PermGen space failure | Eric's Agile Answers<http://www.jroller.com/agileanswers/entry/preventing_java_s_java_lang> PermGen Out of Memory — Mifos - Technology that Empowers Microfinance<http://www.mifos.org/developers/wiki/PermGenOutOfMemory> re: running out of permgen memory when deploying/undeploying several times<http://mail-archives.apache.org/mod_mbox/beehive-user/200506.mbox/%[email protected]%3e> Confluence out of perm gen space - ADFG Confluence Information - Alaska Department of Fish and Game Confluence<http://www.admin.adfg.state.ak.us/confluence/display/adfgconfinf/Confluence+out+of+perm+gen+space> java.net Forums : Diagnosing PermGen issues ...<http://forums.java.net/jive/thread.jspa?threadID=56886> Search results for out of permgen - MarkMail<http://markmail.org/message/mox2vsa6txv46npz> Running out of permgen space - Spring Community Forums<http://forum.springframework.org/showthread.php?t=54150> Atlassian Forums: Running out of PermGen Space ...<http://forums.atlassian.com/message.jspa?messageID=257245099> [#JBPAPP-469] Out of perm-gen memory when deploying applications to the productions configuration - jboss.org JIRA<https://jira.jboss.org/jira/browse/JBPAPP-469;jsessionid=C1F0DF8E1FECC365CFD3E6FD8860C636> Java JVM GC, PermGen, and Memory Options<http://www.brokenbuild.com/blog/2006/08/04/java-jvm-gc-permgen-and-memory-options/> _______________________________________________ devs mailing list [email protected] http://lists.xwiki.org/mailman/listinfo/devs
