Introduction to Oracle JRockit Real Time

Using Oracle JRockit Real Time with Other Oracle Products

Oracle JRockit Real Time is fully compatible with Oracle JRockit JVM R27.6 and is therefore supported by Oracle when used with Oracle products that are supported with Oracle JRockit JVM R27.6. This chapter describes the tasks necessary for using JRockit Real Time with other Oracle products. It includes information on the following subjects:

Getting Started

To use JRockit Real Time with an Oracle product, you must download and install the Oracle product and JRockit Real Time separately and then make the following configuration changes:

Update the Oracle product start script to use the WLRT JAVA_HOME.
Remove any -Xgc: and -Xgcprio: parameters from the Java command line.
Add -Xgcprio:deterministic and -Xpausetarget=nnms (where nn is the desired pause target) to the Java command line

Selecting a lower pause target will result in shorter garbage collection pauses, with the caveats outlined in Tuning the Pause Target in the Oracle JRockit JVM iagnostics Guide. Here are some recommendations for the most common combinations:

Oracle WebLogic Server

Oracle WebLogic Server can be enabled to use JRockit Real Time either by following the generic instructions above or by using a preconfigured domain template. Oracle has prepared templates for the following Oracle WebLogic Server versions:

Oracle WebLogic Server 8.1 domain template.
Oracle WebLogic Server 10.0 domain template.

Oracle has verified that larger J2EE applications (including SPECjAppServer2004) works well with a 30ms pause targets. Lower pause targets might be possible for smaller J2EE applications or faster hardware.

WebLogic Event Server

The Oracle WebLogic Server has been extensively optimized for use with Oracle JRockit Real Time, so a good starting point for the pausetarget is 10 ms. Oralce has verified that small WLEvS applications on recent x86 hardware work with pausetargets down to 3 ms. For more information on tuning Oracle WebLogic Server with JRockit Real Time, see the Oracle WebLogic Server documentation.