A lower bound for quantifying overlap effects: an empirical approach

Among the many features that are implemented in today's microprocessors there are some that have the capability of reducing the execution time via overlapping of different operations. Overlapping of instructions with other instructions and overlapping of computation with memory activities are the main way in which execution time is reduced. In this paper we will introduce a notion of overlap and its definition, and a few different ways to capture its effects. We will characterize some of the ASCI benchmarks using the overlap and some other quantities related to it. Also, we will present a characterization of the overlap effects using a lower bound derived empirically from measured data. We will conclude by using the lower bound to estimate other components of the overall execution time.