Figure 9-20. Shown is the effect of workload balancing on response time. During peak processing time, the response time is at point A. By shifting some of the workload to another time, the arrival rate is reduced from 24 trx/ms to 18 trx/ms, resulting in a significant response time reduction. Notice the response-time curve does not shift, but rather the system activity has shifted.

Now, we finally answer the question posed at the beginning of the chapter: What kind of performance improvement can we expect? I'll start with some direction and words of caution. Then I will move directly into a series of exercises to demonstrate step by step how you can creatively apply all the material presented in this book to anticipate the impact of a solution and improve the situation.

With our performance-improving objective in mind, we will continue to responsibly simplify and to use abstraction. Simplification is the key to understanding, and to communicating technical concepts and information. We want to make our performance presentation memorable. We want to motivate change.