Index-Compact Garbage Collection

Automatic garbage collection is currently adopted by many object-oriented programming systems. Among the many variants, a markcompact garbage collector offers high space efficiency and cheap object allocation, but suffers from poor virtual memory interactions. It needs to linearly scan through the entire available heap, triggering many page faults which may lead to excessively long collection time. We propose building an object reference index while tracing the heap, which in the following stages can be used to directly locate the live objects. As the dead objects are not touched, the collection time becomes dependent only on the size of the live data set. We have implemented a prototype in Jikes RVM, which shows promising results with the SPECjvm98 benchmarks.