Speeding up WSCP and administration client initialization in V4 of WebSphere Application Server (IBM JDK V1.3.x)
 Technote (FAQ)
 
Problem
In WebSphere Application Server V4.x, the time required for WSCP and administration client initialization is signficantly increased by the overhead of the Java Just-In-Time Compiler (JITC) for those platforms using IBM JDK/SDK V1.3.x.
 
Cause
The JITC is invoked by default for the JVM during the invocation of wscp or the adminclient. JITC compiles the java classes, optimizing the binaries for maximum performance for subsequent invocation under that same process. In IBM's JDK/SDK V1.3.x, more optimization occurs beyond what was performed in V1.2.x, and on the AIX platform even more optimization is done than on other platforms. Thus a significant one-time overhead occurs so that any subsequent invocations will have better performance. However, if the process is an interactive process that runs and then terminates (such as wscp or the administration client), then the performance benefit from the JITC compilation may never be realized and the intensive JITC optimization is unneeded overhead.
 
Solution
The time required for WSCP or adminclient initialization can be reduced significantly by changing the JITC optimization by specifying the -Xquickstart parameter. For example, improvements for wscp initialization in Windows platforms may be as much as 3 to 6 seconds, while improvements for wscp initialization on AIX may be as high as 45 to 60 seconds. JITC optimization overhead can be reduced via the -Xquickstart parameter at the expense of slightly less efficient compiled executables (5 to 10 percent reduction in performance for long runnings tasks). The examples below show how to use the parameter to improve wscp initialization, but a similar technique can be extrapolated for use with adminclient.sh or adminclient.bat.

To disable JITC for wscp:

- For Windows/NT/2000/XP, and for AIX: Add the -Xquickstart parameter in the java invocation within wscp.bat or wscp.sh

Example:

...
%JAVA_HOME%\bin\java %WSCPCLIENTSAS% -Xquickstart -Dserver.root=%WAS_HOME% -Dws.ext.dirs=%WAS_EXT_DIRS% -classpath %WAS_CLASSPATH% com.ibm.ws.bootstrap.WSLauncher com.ibm.ejs.sm.ejscp.WscpShell %EXT% %

If you have designed your wscp scripts in such a way that keeps the wscp process active for subsequent invocations, then the -Xquickstart parameter would probably not be desirable.

 
 


Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server > Administrative Console (all non-scripting)
Operating system(s): Windows
Software version: 4.0
Software edition:
Reference #: 1078467
IBM Group: Software Group
Modified date: Oct 3, 2003