Dynamically controlling false sharing in distributed shared memory

Abstract

Distributed shared memory (DSM) alleviates the need to program message passing explicitly on a distributed-memory machine. In order to reduce memory latency, a DSM replicates copies of data. This paper examines several current approaches to controlling thrashing caused by false sharing in a DSM. Then it introduces a novel memory consistency protocol, writer-owns, which detects and eliminates false sharing at run time. In iterative computations, where the data is accessed similarly every iteration, the writer-owns protocol can have tremendous benefits because the overhead of eliminating false sharing is only incurred once. Performance results show that the writer-owns protocol is competitive with and often better than existing approaches.