ARMA models of program behaviour

Abstract

In models of virtual memory computer systems, it is generally assumed that the time intervals between the page (or segment) faults, often called lifetimes, are independent from each other. Due to the phase-transition behaviour in many real programs this is not always true, and strong correlations may exist between successive lifetimes. These correlations may have a notable effect on the system behaviour. This paper describes a series of experiments where autoregressive -moving average (ARMA) models are used to describe the correlation structure in sequences of lifetimes. It is shown that many real program executions can be described with models having four parameters only, i.e. with the ARMA(1,1) models. The models can be used as parts of simulation models for instance, and they also give us better understanding about the program behaviour in general.