A Relativistic Enhancement to Software Transactional Memory

Relativistic Programming is a technique that allows low overhead, linearly-scalable concurrent reads. It also allows joint access parallelism between readers and a writer. Unfortunately, it has so far been limited to a single writer so it does not scale on the write side. Software Transactional Memory (STM) is a technique that allows programs to take advantage of disjoint access parallelism on both the read-side and write-side. Unfortunately, STM systems have a higher overhead than many other synchronization mechanisms so although STM scales, STM starts from a lower baseline. We propose combining relativistic programming and software transactional memory in a way that gets the best of both worlds: low-overhead linearly-scalable reads that never conflict with writes and scalable disjoint access parallel writes. We argue for the correctness of our approach and present performance data that shows an actual implementation that delivers the promised performance characteristics