System.gc() still resulting in garbage collections with -XX:+DisableExplicitGC

[James Nichols]

Ok, this was PEBKAC.

I recently installed the JBoss ON agent (which is Java) and was running
jstat on that, not my Jboss application server.  You did help though, since
I started looking at my gc.dat log closely and it wasn't jiving with what I
was seeing in Jstat.

Thanks!!!
Jim


On Mon, Apr 14, 2008 at 3:00 PM, Y Srinivas Ramakrishna <
Y.S.Ramakrishna at sun.com> wrote:

> That is weird and unexpected (and could well be instrumentation error).
> Could you post a
> snippet of the GC log (/var/log/jboss/gc.dat) showing a portion where such
> System.gc()'s may
> be occurring?
>
> -- ramki
>
> ----- Original Message -----
> From: James Nichols <jamesnichols3 at gmail.com>
> Date: Monday, April 14, 2008 11:31 am
> Subject: System.gc() still resulting in garbage collections with
> -XX:+DisableExplicitGC
> To: hotspot-gc-use at openjdk.java.net
>
>
> > Hello,
> >
> > I'm running with the following JVM arguments:
> >
> >  -server -Xms4096m -Xmx4096m -XX:NewSize=1228M -XX:MaxNewSize=1228M
> > -XX:MaxTenuringThreshold=4 -XX:SurvivorRatio=6 -XX:+ScavengeBeforeFullGC
> > -XX:PermSize=256M -XX:MaxPermSize=256M -XX:-UseConcMarkSweepGC
> > -XX:+UseParNewGC -XX:ParallelGCThreads=3 -XX:+CMSParallelRemarkEnabled
> > -XX:+CMSClassUnloadingEnabled -XX:+CMSPermGenSweepingEnabled -verbosegc
> > -XX:+DisableExplicitGC -XX:+PrintTenuringDistribution
> -XX:+PrintGCDetails
> > -XX:+PrintGCTimeStamps -XX:+PrintHeapAtGC
> > -XX:+PrintGCApplicationConcurrentTime -XX:+PrintGCApplicationStoppedTime
> > -XX:+PrintClassHistogram -Xloggc:/var/log/jboss/gc.dat
> > -Dsun.net.client.defaultConnectTimeout=10000
> >
> > Using Jstat, I see a bunch of System.gc() calls showing up:
> >
> > Timestamp         S0     S1     E      O      P     YGC     YGCT    FGC
> > FGCT     GCT    LGCC                 GCC
> >        189869.1   0.00   0.00   1.80  21.36  89.74   3109   15.401  3012
> > 288.886  304.288 System.gc()          No GC
> >
> >
> > Any ideas as to why I'm still getting these even though I have
> > -XX:+DisableExplicitGC set?
> >
> > Jim
> > _______________________________________________
> > hotspot-gc-use mailing list
> > hotspot-gc-use at openjdk.java.net
> > http://mail.openjdk.java.net/mailman/listinfo/hotspot-gc-use
>
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