Dynamic Grouping in an Object-Oriented Virtual Memory Hierarchy

Abstract

Object oriented programming environments frequently suffer serious performance degradation because of a high level of paging activity when implemented using a conventional virtual memory system. Although the fine-grained, persistent nature of objects in such environments is not conducive to efficient paging, the performance degradation can be limited by careful grouping of objects within pages. Such object placement schemes can be classified into four categories -the grouping mechanism may be either static or dynamic and may use information acquired from static or dynamic properties. This paper investigates the effectiveness of a simple dynamic grouping strategy based on dynamic behaviour and compares it with a static grouping scheme based on static properties. These schemes are also compared with near-optimal and random cases.

Marea: An Efficient Application-Level Object Graph Swapper.

“…Operating systems have been supporting virtual memory since a long time [Den70,Sta82,CH81,WWH87,KLVA93]. Virtual memory is transparent in the sense that it automatically swaps out unused memory organized in pages governed by some strategies such as the leastrecently-used (LRU) [CH81,CO72,Den80,LL82].…”

Do Object-Oriented Languages Need Special Hardware Support?

“…Since the performance impact of these misses is relatively high, software optimizations to reduce them may be worth investigating. Finally, even though cache-level data locality is good, page-level locality may be poor [WWT87] and thus needs to be studied.…”