10.1 Performance Issues

Performance has at least four aspects: execution speed, code size, compilation speed, and linking speed. Although all four are important, most people think of execution speed when performance is mentioned, and most of the guidelines in this chapter focus on execution speed.

Performance is influenced by many factors, including the compilation software, hardware, system load, and coding style. While only coding style is typically under the control of the programmer, the other factors have so much influence that it is impossible to make flat statements such as "case statements are more efficient than if-then-else structures." When performance is critical, you cannot assume that a coding style that proves more efficient on one system will also be more efficient on another. Decisions made for the sake of performance must be made on the basis of testing the alternatives on the actual system on which the application will be fielded.