Overview

What is computer systems performance evaluation and prediction and why are these techniques necessary in today's world of ever decreasing computer systems cost? To answer these questions requires the computer engineer to understand how all elements of a computer system come into play in realizing a user's application and its implementation, fielding, and maintenance. All aspects of a computer system's lifetime are important when trying to understand issues of performance. It is not sufficient to simply buy the "best" general-purpose computing machine one can find today and then implement the intended application on it. One must consider how the system will fit into an existing computing facility and what the requirements on the computer system are today and what these requirements will be during the computer system's lifetime.

The most important driving factors when designing, building, and fielding a computer system are that it performs the intended function correctly, performs the intended function efficiently, and does so in a cost-effective manner. Therefore, initial design for correctness may often outweigh performance and cost as the driving force. Having said this, it is often the case that computer systems designers think of performance, cost, and correctness interchangeably. They are, however, different. A correct design may not imply one that performs blazingly fast or is very cost effective. This may be due to other considerations for example, we may need to trade off performance or perfect correctness to save cost per unit. This is more typical of engineering designs. We do not always...