Configuring the k-cluster using heapdump
 Technote (FAQ)
 
Problem
HeapAnalyzer can be used to determine an appropriate k-cluster value for your JVM, providing a healthier java heap
 
Cause
HeapAnalyzer, available on www.alphaworks.ibm.com for analyzing Java™ heap dumps, can be used with a heapdump to determine an appropriate k-cluster value for your JVM.
 
Solution
1) After loading the heapdump into HeapAnalyzer, you will first be presented with a window giving a summary of the heapdump. Six lines down the recommended k-cluster is displayed (and highlighted below).




2) Using the k-cluster value above, in this example 31203, modify your k-cluster value by adding the following to your generic JVM arguments.

-Xknnnn

Where nnnn specifies the maximum number of classes the kCluster contains. -Xk instructs the JVM to allocate space for nnnn class blocks in kCluster.

IBM recommends that you add about 10% to the reported value (for example: 31203 > 34400 ). In this example, -Xk34400 is a good setting.

 
Related information
Using HeapAnalyzer to analyze Java heap usage and detec
Heap Fragmentation with IBM JVMs
 
 
 


Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server > Out of Memory
Operating system(s): Linux
Software version: 4.0
Software edition:
Reference #: 1230492
IBM Group: Software Group
Modified date: Feb 15, 2006