See Par New GC 2 time slower on Sun T5220 than on Sun V440

[Jon Masamitsu]

Just FYI on this mail.

We made a guess that the GC time was being dominated
by Reference processing.  They are using jdk5 and
in ParNewGC in jdk5 Reference processing
is done serially.   Josh was able to make a
change in the application to reduce that number of
SoftReferences and the problem went away.

Josh Wo wrote On 11/18/08 16:49,:

>Hi Ramakrishna/Jon,
>
>I am with www.hotwire.com. I logged a Sun JDK case with Case # 66145049 as when we upgrade our Sun Fire v440 machine (4 cpu) with Sun SPARC-Enterprise-T5220 (showing 64 cpus using prstat) machine. During the load test, we saw our GC become more than 2 times slower than the old machine and see about 10% lower in the throughput. We have kept JVM setting the same but only increase the thread count of Weblogic (10mp1) work manager.
>
>I am wondering if you have any insight on why this is happening and if there are known issues/workaround. Any advice will be helpful. I have attached the GC output in the zip file.
>
>nohup-Nov10-11h09-wlviewstart-sjsp01.out is the v440 old machine, where GC is much better
>nohup-Nov18-10h11-wlviewstart-sjsp03.out is the T5220 new machine, which is much more powerful but GC appears to be bad and we got worse throughput.
>
>Here is the java command line used on both machine
>Java command line
>
>-Xms2410m -server -XX:ThreadStackSize=256 -verbose:gc -XX:+PrintGCTimeStamps -XX:+PrintClassHistogram -XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XX:+CMSParallelRemarkEnabled -XX:+UseCMSCompactAtFullCollection -XX:CMSFullGCsBeforeCompaction=0 -XX:+HandlePromotionFailure -XX:CMSInitiatingOccupancyFraction=68 -XX:+UseCMSInitiatingOccupancyOnly -Dsun.net.spi.nameservice.provider.1="dns,sun" -Dsun.net.spi.nameservice.nameservers=172.28.2.220,172.26.2.220 -Dsun.net.spi.nameservice.domain=stg.hotwire.com -XX:CMSMarkStackSize=32M -XX:CodeCacheMinimumFreeSpace=2M -XX:ReservedCodeCacheSize=64M -Xmx2410m -XX:NewSize=512M -XX:MaxNewSize=512M -XX:MaxTenuringThreshold=6 -XX:SurvivorRatio=5 -XX:TargetSurvivorRatio=80  -XX:MaxPermSize=256M -XX:-DisableExplicitGC -Dorg.apache.commons.logging.Log=org.apache.commons.logging.impl.Jdk14Logger -Dhotwire.db.creds=/opt/p4/phoenix/10.11/deploy/stage/hw.db.creds  -Dtangosol.coherence.mode=prod -Djava.endorsed.dirs=/opt/p4/3rdparty/apache/xalan/2.7.0hw -XX:CMSMaxAbortablePrecleanTime=1 -XX:+PrintGCDetails -XX:+PrintHeapAtGC -XX:+PrintTenuringDistribution -Djava.awt.headless=true -Dweblogic.client.socket.ConnectTimeout=5 -Dtangosol.coherence.distributed.localstorage=false -Dtangosol.coherence.cacheconfig=/opt/p4/phoenix/10.11/deploy/coherence-cache-config.xml -Dtangosol.coherence.log=jdk -Dtangosol.coherence.log.level=5 -Djavax.xml.transform.TransformerFactory=org.apache.xalan.xsltc.trax.TransformerFactoryImpl -Dweblogic.http.session.maxConcurrentRequest=5  -Dweblogic.management.server=http://swc01:7004 -Dcom.sun.management.jmxremote.port=8004 -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dtangosol.coherence.management.remote=true -Dweblogic.Name=wlview1 -Dtangosol.coherence.member=wlview1   -Dweblogic.Domain=phoenix -Dweblogic.RootDirectory=/opt/p4/phoenix/10.11/deploy/stage/weblogic -Dwls.home=/opt/p4/3rdparty/bea/weblogic/10.0mp1/server -Dbea.home=/opt/p4/3rdparty/bea/weblogic/10.0mp1 -Dweblogic.connector.ConnectionPoolProfilingEnabled=false -Dcom.bea.wlw.netui.disableInstrumentation=true -D_Offline_FileDataArchive=true
>
>Thanks,
>Josh
>
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