Modeling heap data growth using average liveness

Abstract

Most of today's programs make use of a sizable heap to store dynamic data. To characterize the heap dynamics, this paper presents a set of metrics to measure the average amount of data live and dead in a period of execution. They are collectively called average liveness. The paper defines these metrics of average liveness, gives linear-time algorithms for measurement, and discusses their use in finding the best heap size. The algorithms are implemented in a Java tracing system called Elephant Tracks and evaluated using the Dacapo benchmarks running on the Oracle HotSpot and IBM J9 Java virtual machines.