Remembered sets can also play cards
Antony L. Hosking, Richard L. Hudson · 1999
Remembered sets and dirty bits have been proposed as alternative implementations of the write barrier for garbage collection. There are advantages to both approaches. Dirty bits can be efficiently maintained with minimal, bounded overhead per store operation, while remembered sets concisely, and accurately record the necessary information. Here we present evidence to show that hybrids can combine the virtues of both schemes and offer competitive performance. Moreover, we argue that a hybrid can better avoid the devils that are the downfall of the separate alternatives. 1 Introduction Generational garbage collectors [6, 10, 11] achieve short pause times partly because they separate heap-allocated objects into two or more generations and do not process all generations during each collection. Empirical studies have shown that in many programs most objects die young, so separating objects by age and focusing collection effort on the younger generations is a popular strategy. However, any ...