Tune Java virtual machines

 

Overview

The appserver, being a Java process, requires a Java virtual machine (JVM) to run, and to support the Java applications running on it. As part of configuring an appserver, you can fine-tune settings that enhance system use of the JVM. In addition to the following tuning parameters, see also Java memory tuning tips.

Use the following JVM parameters, including garbage collection options for IBM Developer Kit 1.3.1, to tune the Java virtual machine. For instructions on view and change the JVM configuration , go to Using the JVM For information on specifying any of the following settings, go to Java virtual machine settings.

Use the following JVM parameters, including garbage collection options for IBM Developer Kit 1.4.1, to tune the Java virtual machine. For instructions on view and change the JVM configuration , go to Using the JVM. For information on specifying any of the following settings, go to Java virtual machine settings.

• Specify any or all of the following generic JVM arguments.These optional command line arguments are passed to the Java virtual machine code that starts the appserver process.

  • Quickstart (-Xquickstart)

  • Avoiding class verification (-Xverify:none)

  • Class garbage collection (-Xnoclassgc)

  • Garbage collection threads (-Xgcthreads)

  • Garbage collection policy (-Xgcpolicy)

  • Sun JDK 1.3 Generational Garbage Collection (-XX)

    You can find more information about generational garbage collection at    http://java.sun.com/docs/hotspot/gc/index.html .

  • Sun JDK 1.4.1 Generational Garbage Collection (-XX)

    You can find more information about generational garbage collection at    http://java.sun.com/docs/hotspot/gc/index.html .

  • Sun Java Development Kit 1.3 HotSpot JVM warm-up (-server)

  • Sun Java Development Kit 1.4.1 HotSpot JVM warm-up (-server)

  • Heap compaction (-Xnocompactgc)

  • Initial system heap size (-Xinitsh)

• Set the initial heap size.

• Set the maximum heap size.

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Using the JVM
    

 

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