Compile-Time Concurrent Marking Write Barrier Removal

Abstract

Garbage collectors incorporating concurrent marking to cope with large live data sets and stringent pause time constraints have become common in recent years. The snapshot-at-the-beginning style of concurrent marking has several advantages over the incremental update alternative, but one main disadvantage: it requires the mutator to execute a significantly more expensive write barrier. This paper demonstrates that a large fraction of these write barriers are unnecessary, and may be eliminated by static analysis.