Response time is the time required to execute a specified task, for example, to call an EJB method or submit a JSP form request. For end users, response time provides the key measurement of performance.
In client-side coding, you can minimize perceived response time by displaying partial results or status bars. However, in server-side coding, all you can do is minimize the in-server response time to an acceptable level. It helps to break down the response time into time spent in each component and subsystem. Figure 1-1 illustrates the processing of a Web form request to a JSP that calls an EJB component which in turn executes a remote database query. A slowdown can occur in any of these components. When tuning, you must isolate the part of your deployment that is causing the delay.
Figure 1-1: Response time breakdown
