1. Definitions

The enhancement can take many forms, such as improved hardware features, faster memory, faster functional units, shorter pipelines, improved data allocation in a banked memory system, improved vectorization by a compiler, or multiple processors. Most enhancements do not apply uniformly to a task (system clock rate being an exception). Hence, it is important to factor out the different parts of a computation and consider the speedup for each part. As an example, assume that there are two sections of a program, one which achieves a speedup S, and a second which is not affected. Let the fraction of the time Told which is affected by the enhancement be f . Then, the total time after the enhancement is