Using WebLogic JRockit 8.1 SDK
The configuration options described elsewhere in this user guide can be set to optimize WebLogic JRockit JVM performance with both BEA WebLogic Server and BEA WebLogic Workshop. This chapter defines these optimal settings and discussed how to use the JVM with these applications. It includes information on the following subjects:
BEA WebLogic JRockit JVM is certified for use with BEA WebLogic Server. This section includes information on the following subjects:
For details on certified and supported platform combinations of WebLogic Server with WebLogic JRockit 8.0, please refer to the following Web pages:
http://www.bea.com/products/weblogic/server/
http://www.bea.com/products/weblogic/jrockit/
WebLogic JRockit is the default production JVM shipped with WebLogic Server, although you can use another VM, such as Sun Microsystem's HotSpot JVM as a development VM. To ensure that WebLogic JRockit is the JVM running with your instance of WebLogic Server, at the command line, type:
java -showversion
If WebLogic JRockit is running, the system will respond:
java version "1.4.1_05"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.1_05)
BEA WebLogic JRockit(R) Virtual Machine (build
8.1-1.4.1_05-win32-CROSIS-20030317-1550, Native Threads, Generational
Concurrent Garbage Collector)
Note: This example assumes you are using the native thread method (the default) and generational concurrent garbage collector (default when maximum heap size is larger than 128 MB).
If you are starting WebLogic JRockit JVM from the WLS Node Manager, you need to enter the fully-qualifying path, as shown above, in the Java Home field on the Remote Start Page; for example:
\bea\jrockit81_141\bin\java
You can enable the management server from the WLS Node Manager by doing the following:
For more information on using the Node Manager, please refer to the Overview of Node Manager in Configuring and Managing WebLogic Server.
If you started the server or cluster of servers with the Node Manager and specified an absolute pathname to WebLogic JRockit JVM's top-level directory in the Java Home field on the Node Manager's Remote Start page, you can set any option from this page, too. Simply enter the option and any arguments in the Arguments field.
For more information on using the Node Manager, please refer to the Overview of Node Manager in Configuring and Managing WebLogic Server.
To use the WebLogic JRockit JVM instead of the Sun JVM, you need to increases the initial heap size to 64 MB (-Xms:64m
)and the maximum heap size to at least 200 MB (-Xmx:200m
). In addition, the following defaults are used:
These settings are normally used for initial development. If you want to improve WebLogic JRockit performance, you can try one of the following, bearing in mind that all applications are different and you need to verify which settings give the best performance in each case:
-Xms
and -Xmx
). -Xgc:singlecon
) or parallel (-Xgc:parallel
). Note that if you select parallel as your garbage collector, the -Xns
setting will have no affect on processing (see Setting the Size of the Nursery).For more information on tuning WebLogic JRockit, please refer to Tuning WebLogic JRockit JVM.
If you run WebLogic Server with WebLogic JRockit JVM, you can use the WebLogic Server Administration Console to view runtime data about the VM and the memory and processors on the computer hosting it.
To monitor WebLogic JRockit JVM, do the following:
The JRockit tab displays monitoring information.
To view additional data about WebLogic JRockit, such as how long it spends in a specific method, use the WebLogic JRockit Management Console, as described in Using the WebLogic JRockit JVM Management Console.
Warning: Thin threads is experimental functionality in this version of JRockit, and is not recommended for general use. This feature is subject to change without notice.
The JRockit high performance thread system (Thin Threads, -Xthinthreads
) and the native I/O system of WebLogic Server are incompatible as they both use asynchronous I/O. To avoid problems you must disable the native I/O system of WebLogic Server when running JRockit using thin threads. The native I/O is disabled automatically in WebLogic Server if JRockit is using thin threads, even if it is turned on in the corresponding WebLogic Server configuration file. In their respective default setups, WebLogic JRockit JVM does not use thin threads and WebLogic Server uses native I/O.
When you switch to WebLogic JRockit JVM in WebLogic Server, any changes to the VM and start-up setting, should be handled by the WLS Configuration Wizard. Additionally, if any installation-wide scripts must be updated due to the switch, these will also be handled by the WLS Configuration Wizard.
Among information that needs to be changed when switching to WebLogic JRockit JVM are:
JAVA_HOME
variable needs to be changed to the absolute pathname to the top BEA directory; for example, c:\bea\jrockit81
. You can also change the JAVA_HOME
variable from the Node Manager's Remote Start page by entering the absolute pathname in the Java Home field.
JAVA_VENDOR
variable to BEA
.You will also need to restart any servers that are currently running.
For complete details on switching to WebLogic JRockit JVM from another JVM, please refer to Migrating to WebLogic JRockit. For more information on using the Configuration Wizard when switching to WebLogic JRockit, please refer to Changing the JVM that Runs Servers.
To switch the virtual machine when WebLogic Server is running as a service, do the following:
(HKEY_LOCAL_MACHINE/SYSTEM/ControlSet001/Services/{ServiceName}).
If you are running JRockit with BEA WebLogic Workshop, we recommend that you use the same configuration parameters specified for WebLogic Server in Tuning WebLogic JRockit for WebLogic Server.