I havent used JMX so this might not be relevant But I'd suggest the following.
1) Install jvmstat it works with java 1.6 and use Visualgc to visual monitor the garbage collection. Note: you need to run tomcat as the same user as the account running visualgc use "jps" to find out the java vm ID 2) Use the server jvm (ie one in JAVA_HOME/jre/bin/server 3) Tweak your GC settings (try seeting your initial memory pool and Max mem pool to he same value (say 128MB) and your Thread stack size to say 32KB then add the a java options -XX:+UseConcMarkSweepGC -XX:NewSize=32M -XX:MaxNewSize=32M). Note on windows the Java options need to be on separate lines. Allocating more memory to the JVM isn't always best. Although it means the GC runs less often it causes it to take longer to run. Ie large pauses. Large pauses can cause timeouts resulting in retries causing more work resulting in more pauses and things go down hill from there. Ensure that your app is closing database connections as soon as it is finished with them and that error conditions are correctly handled such that database connections are aways closed. See "Random Connection Closed Exceptions" in (http://tomcat.apache.org/tomcat-6.0-doc/jndi-datasource-examples-howto. html) For template code. Michael Simmons Technical Advisor/Programmer Information Technology Services (ITS) (Office of Finance and Resources) Telephone: 6488 4792 Fax: 6488 3861 MBDP: M463 Email: [EMAIL PROTECTED] -----Original Message----- From: karthikn [mailto:[EMAIL PROTECTED] Sent: Wednesday, 4 June 2008 10:16 PM To: Tomcat Users List Subject: Re: JMX Perform GC TOMCAT 5.5.23 Hi On a simulator System (same as Production ) with JMeter Load test performance was good and CPU utilization was not beyond 40% for 900+ users But for the same application in Production, We notice Constantly JAVA is 100% CPU utilization. Any Ideas ? with regards Karthik we were able to Caldarale, Charles R wrote: >> From: karthikn [mailto:[EMAIL PROTECTED] >> Subject: Re: JMX Perform GC TOMCAT 5.5.23 >> >> Reason : We have a Production TOMCAT 5.5.23 where in CPU >> Utilization for JAVA is going 100% , >> > > And for some reason you think a GC will fix that? > > >> This Tomcat needs to be restarted started every 12+ hrs We suspect HP >> supported JDK1.6 bing the culprit for the same >> > > A slight possibility, but in nearly all such cases, it's the application, not the JVM or Tomcat. > > - Chuck > > > THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers. > > --------------------------------------------------------------------- > To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, > e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > > --------------------------------------------------------------------- To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
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