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From "Shapira, Yoav" <>
Subject RE: Java Process Pegging
Date Fri, 16 May 2003 17:08:53 GMT

So many variables in your environment, it's hard to tell.

Have you ruled out garbage collection as the cause?  You've run with
-verbose:gc and saw that during this high CPU usage period, the JVM was
NOT repeatedly doing full GCs?

I doubt it has to do with tomcat, but you can narrow things further by
enabling debug="99" everything in tomcat's server.xml, so you can see
what tomcat is doing.

Yoav Shapira
Millennium ChemInformatics

>-----Original Message-----
>From: William Dinyes []
>Sent: Friday, May 16, 2003 12:46 PM
>To: Tomcat Users List
>Subject: Java Process Pegging
>Sensitivity: Private
>Alrighty, so I've scanned the archives and read all the documentation I
>find, and still I seem to be missing something.
>I've got Tomcat 4.1.24 from binary tarball, Apache 2.0.40 from RH 9
>mod_jk2 compiled from source, and Java 1.4.1 from Sun RPM.
>My CATALINA_OPTS are "-server -Xmx1024m -Xms1024m -XX:NewRatio=12
>-XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XX:+UseAdaptiveSizePolicy"
><Connector> uses minProcessors="5" maxProcessors="100" among other
>It's a 2-proc box with hyperthreading so it appears as a 4-proc box to
>Hat 9, 2GB of physical RAM installed.
>And yet, shortly (sometimes an hour, sometimes 3, one memorable time 20
>minutes) after the system starts, the Java process (it appears to spawn
>one when viewed in pstree or top) pegs at 99.9% of CPU, and eventually
>responding to any requests of any kind.  I thought it might be memory,
>garbage collection management, which is why the funky flags on
>The site (same code base) in question runs well on Apache 1.3.27,
>4.0.6 and mod_webapp 1.2.0-dev on some RH 7.2/7.3 servers without this
>issue (though they do get rebooted every night to clear memory - a
>my predecessor).  I'm trying to upgrade our systems to something a
>newer (read: better patched), and this is just floggin' my noggin'.
>Anyone else have this issue?  Got a fix?  A hint as to where else to
>It's one of 7 servers that combined serve around 30,000 unique visitors
>day, so they keep pretty busy.
>William Dinyes
>Website Administrator
>10030 N. 25th Ave.
>Phoenix, AZ 85021
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