WebSphere Application Server for z/OS uses workload management (WLM) services to collect some of the accounting and performance data.
The information gets presented back to the installation through RMF and RMF-written SMF records. In addition, WebSphere Application Server for z/OS has its own SMF records that collect additional domain specific information for WebSphere Application Server for z/OS. First, unless you need the SMF records or RMF data, turn them off using the Administration application and the SMFPRMxx parmlib statement. Refer to Setting up SMF and Enabling SMF recording. You can also use the SMFPRMxx parmlib statement to control the detail of the WebSphere for z/OS SMF records. If you do need SMF information, you should review the SMF parmlib to ensure you are collecting only the data that you need, both record types and detail.
Recognize that you can classify work into service classes based on userid, server name, server instance name, and transaction class. Refer to Classifying WebSphere transaction workload for WLM. You should ensure that you classify the control regions as reasonably high-performing system tasks. Refer to Workload management (WLM) tuning tips for z/OS. Classification can be done in many ways now. To classify Enterprise JavaBeans (EJB) files, you can use the server name and user. Message-driven beans and servlet or JavaServer Pages (JSP) files use a special classification document.