On models for object lifetime distributions

Analytical models of memory object lifetimes are appealing because having t hem would enable mathematical analysis or fast simulation of the memory man agement behavior of programs. In this paper, we investigate models for obje ct lifetimes drawn from programs in object-oriented languages such as Java and Smalltalk. We present certain postulated analytical models and compare them with observed lifetimes for 58 programs. We find that observed lifetim e distributions do not match previously proposed object lifetime models, bu t do agree in salient shape characteristics with the gamma distribution fam ily used in statistical survival analysis for general populations.