Underlying the performance monitoring capabilities in WAS is the Performance Monitoring Infrastructure (PMI), which collects performance information from a number of WAS runtime components. PMI in WAS V5 is implemented as a series of JMX (Java Management Extensions) MBeans (Management Beans), leveraging the JMX infrastructure available in WAS V5. The use of MBeans for the PMI implementation adds an additional PMI client type to WAS V5 from prior versions. Not only are the Performance Servlet HTTP client, PMI API Java Client, and Tivoli Performance Viewer (TPV) available, but a JMX Java client is also supported. The interaction between the clients and the WAS runtime is depicted in Figure 25-1.