Concurrent GC leveraging transactional memory

We predict that the ever-growing number of cores on our desktops will require a re-examination of concurrent programming. Two technologies are likely to become mainstream in response: Transactional memory provides a superior programming model to traditional lock-based concurrency, while Concurrent GC can take advantage of multiple cores to eliminate perceptible pauses in desktop applications such as games or Internet telephony. This paper proposes a combination of the two technologies, producing a synergy that improves scalability while eliminating the annoyance of user-perceivable pauses. Specifically, we show how concurrent GC can share some of the mechanisms required for transactional memory. Thus as transactional memory becomes more efficient, so too will concurrent GC. We demonstrate how, using a state of the art software transactional memory system, we can build a state of the art concurrent collector. Our goal was to reduce 90% of pause times to under one millisecond. Of the remainder, we aim for 90% to be under 10ms, and90% of those left to be under 100ms. Our performance results show that we were able to achieve these targets, with pause times between one or two orders of magnitude lower than mainstream technologies.