Hi
Pardon me for Re Posting the content , had posted the same some day's ago
The Web application is simple and uses JNI to connect to UNIX LOCAL
Application
O/s = UNIX 11 PA Risc 2 CPU
SDK : J2SDK16
TOMCAT 5.5.23
RAM = 8 GB
JAVA_OPTS="-server -Xms200m -Xmx2548m -XX:+UseParallelGC -verbose:gc"
SERVER.xml
<!-- Define a non-SSL HTTP/1.1 Connector on port 8080 -->
<Connector port="8080" maxHttpHeaderSize="8192"
maxThreads="400" minSpareThreads="25" maxSpareThreads="75"
enableLookups="false" redirectPort="8443" acceptCount="100"
connectionTimeout="10000" disableUploadTimeout="true" />
Am i doing wrong anything in here.....
with regards
Karthik
Michael Simmons wrote:
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
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