CMS collection keep working during holiday
Y Srinivas Ramakrishna
Y.S.Ramakrishna at Sun.COM
Thu Oct 9 17:16:06 UTC 2008
Hi Kirk --
> of course... look at this
> VM optoins: -Djava.security.policy=.\java.policy -Xms1536M -Xmx1536M
> -XX:NewSize=256M -XX:+PrintGCDetails -XX:+PrintGCTaskTimeStamps
> -XX:+PrintHeapAtGC -Xloggc:gc.log -XX:+PrintReferenceGC
> -XX:+DisableExplicitGC -XX:+UseConcMarkSweepGC -XX:+UseParNewGC
> -XX:SurvivorRatio=4 -XX:CMSInitiatingOccupancyFraction=55
> -XX:TargetSurvivorRatio=90 -XX:SoftRefLRUPolicyMSPerMB=0
Thanks for confirming.
> Perm space is ignored! Does he need to add
> -XX:+CMSClassUnloadingEnabled -XX:+CMSPermGenSweepingEnabled
Right; however, as of 6.0, the second flag is not needed; just
-XX:+CMSClassUnloadingEnabled should suffice.
> Y Srinivas Ramakrishna wrote:
> > The mention of class loaders below reminds me to remind you that
> > CMS by default will not collect class objects. To force CMS
> > to collect classes in the perm gen, you would want to
> > -XX:+CMSClassUnloadingEnabled. Try to see if that made any
> > difference to the apparent inability of CMS to collect
> > those apparently otherwise unreachable objects.
> > -- ramki
> > ----- Original Message -----
> > From: "Ken-- at newsgroupstats.hk" <dragonken at gmail.com>
> > Date: Thursday, October 9, 2008 3:10 am
> > Subject: Re: CMS collection keep working during holiday
> > To: hotspot-gc-dev at openjdk.java.net
> >> Hi,
> >> I have jhat the vm heap but I don't know how to trace the problem.
> I tried
> >> to click HashMap$Entry / HashMap and there is so many instances and
> >> halt my
> >> browser. I found many references to HashMap are
> >> com.sun.jmx.remote.util.OrderClassLoaders at 0x49448a18 (54 bytes) : field
> >> packages
> >> sun.rmi.server.LoaderHandler$Loader at 0x17be85d0 (75 bytes) : field packages
> >> java.security.BasicPermissionCollection at 0x40b740e8 (18 bytes) :
> >> perms
> >> Up to now, I believe my application has no memory leaks as my
> >> application is
> >> running very well without CMS collector and DisableExplicitGC. But
> I need
> >> CMS and DisableExplicitGC in order to have short gc pause time.
> >> There must be somewhere fool the CMS collector. Any idea to shoot the
> >> problem? Is that my application problem or jvm itself?
> >> Thanks and Best Regards,
> >> Ken
> >> --
> >> View this message in context: http://www.nabble.com/CMS-collection-keep-working-during-holiday-tp19773575p19895899.html
> >> Sent from the OpenJDK Hotspot Garbage Collection mailing list
> >> at Nabble.com.
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