I was looking into an performance issue the other day and came by some small interesting changes you could do to your Websphere Application Server to increase performance and remove locks.
The first was located in the file Stores.war/WEB-INF/ibm-web-ext.xml a file that I've never looked at. Seems that the WAS developers enabled support for handling the JSP generation via configuration options in this file. And others in other web archives.
The attributes and their default values are listed below. These values are from a development environment of Websphere Commerce and should differ in production. For instance the reloadInterval is 10.
<jsp-attribute name="disableJspRuntimeCompilation" value="true" /> <jsp-attribute name="reloadEnabled" value="false" /> <jsp-attribute name="reloadInterval" value="10" /> <jsp-attribute name="trackDependencies" value="true" /> <pre-compile-jsps value="true"/>
The interesting part about these configuration options is that you could turn of the JSP compilation if you precompile all your JSPs, this will increases your performance. The reload time here is how often if at all the server should look at the files on disk and recompile them.
In a development environment it's really nice that your JSPs reloads as often as every 5th second. Tracking dependencies between files so when you make a change in a file included in another is also a great feature. But in a production environment you want to turn the reloadEnabled to false so the server don't look for file changes. The pre-compile-jsps tag is used.
I tested to turn of the reload feature because we always deploys JSPs and don't allow changes to the running files in production. Didn't notice any improvement in performance but I think that everything the server could skip should boost performance.
If you want to change the reloadEnabled value without changing files you could change it in the Integrated Solution Console
Applications > Application Types > WebSphere enterprise applications > [Application] > Web Module Properties > JSP and JSF options
You could read more about these settings at http://pic.dhe.ibm.com/infocenter/wasinfo/v8r0/index.jsp?topic=%2Fcom.ibm.websphere.nd.iseries.doc%2Finfo%2Fiseriesnd%2Fae%2Frweb_jspreloading.html