IBM Agent Controller
As mentioned before, the profiling tools work in conjunction with the IBM Agent Controller, which is a separate program from the WAS installation. Thus you need to make sure that the Agent Controller has been installed on the host where you want to monitor the process.
The Agent Controller is a daemon process that enables client applications to launch host processes and interact with agents that coexist within host processes. The Agent Controller interacts with the following components:
The host process contains the application that is to be profiled. This can be a stand-alone Java process or a WAS instance (including an instance running in an IBM WebSphere Studio Application Developer test environment). An Agent Controller must be executing on the same machine as the host controller.
The Java Profiling Agent is a library that provides services to the host process to capture and record the behavior of a Java application, and makes this data available to attached clients. The agent uses the Java Virtual Machine Profiler Interface (JVMPI) to interface with the JVM. A host process can have one or more agents currently running within it.
The Java Profiling Agent can collect detailed information about any application executing in a JVM. The examples in this chapter use the Java Profiling Agent.
The J2EE Request Profiler is an agent that operates in a WAS process and that collects data relating to the execution of the Web application, such as execution of EJBs and servlets. Distributed environments can be profiled by connecting to J2EE Request Profiler agents running on different nodes. The J2EE Request Profiler only provides a subset of the information available from the Java Profiling Agent, since it only looks at the execution of the enterprise components, and not at Java objects and methods that are called from the EJBs and servlets. The J2EE Request Profiler does, however, have the ability to combine data from more than one WebSphere instance, allowing you to analyze and measure the behavior and performance of a distributed application.
A client is a local or remote application that retrieves and displays data that is collected by an agent. A single client can be attached to many agents at once, and can connect to Agent Controllers on local or remote machines. All communication between the client and agents occurs via the Agent Controller. A profiler client is provided with IBM WebSphere Studio Application Developer. The profiling functionality in IBM WebSphere Studio Application Developer V5.1.1 can be accessed from the Profiling and Logging Perspective.
In this chapter, we discuss the profiling of an application running on WAS. Similar techniques can be used to remotely profile applications running in a WebSphere Studio test environment.
Before attempting to profile an application, ensure that the Agent Controller has been started. This can be checked from the Services program in Windows 2000. If the status of the IBM Agent Controller service is not "Started", then it can be started in Windows 2000 by clicking the Start Service button as shown in Figure 17-1.
Figure 17-1 Starting the Agent Controller
WebSphere is a trademark of the IBM Corporation in the United States, other countries, or both.
IBM is a trademark of the IBM Corporation in the United States, other countries, or both.