On Transactional Scheduling in Distributed Transactional Memory Systems

We present a distributed transactional memory (TM) scheduler called Bi-interval that optimizes the execution order of transactional operations to minimize conflicts. Bi-interval categorizes concurrent requests for a shared object into read and write intervals to maximize the parallelism of reading transactions. This allows an object to be simultaneously sent to nodes of reading transactions (in a data flow TM model), improving transactional makespan. We show that Biinterval improves the makespan competitive ratio of the Relay distributed TM cache coherence protocol to O(log(n)) for the worst-case and Θ log(n− k) for the average-case, for n nodes and k reading transactions. Our implementation studies confirm Bi-interval’s throughput improvement by as much as 200% ∼ 30%, over cache-coherence protocol-only distributed TM.