Estimating internal memory fragmentation for Java programs

Abstract

Dynamic memory management has been an important part of a large class of computer programs and with the recent popularity of object oriented programming languages, more specifically Java, high performance dynamic memory management algorithms continue to be of great importance. In this paper, an analysis of Java programs, provided by the SPECjvm98 benchmark suite, and their behavior, as this relates to fragmentation, is performed. Based on this analysis, a new model is proposed which allows the estimation of the total internal fragmentation that Java systems will incur prior to the programs execution. The proposed model can also accommodate any variation of segregated lists implementation. A comparison with a previously introduced fragmentation model is performed as well as a comparison with actual fragmentation values that were extracted from SPECjvm98. Finally the idea of a test-bed application that will use the proposed model to provide to programmers/developers the ability to know, prior to a programs execution, the fragmentation and memory utilization of their programs, is also introduced. With this application at hand developers as well as designers of applications could better assess the stability, efficiency as well reliability of their applications at compile time.