The Case of Using Multiple Streams in Streaming

Off-chip replacement (capacity and conflict) and coherent read misses in a distributed shared memory system cause execution to stall for hundreds of cycles. These off-chip replacement and coherent read misses are recurring and forming sequences of two or more misses called streams. Prior streaming techniques ignored reordering of misses and not-recently-accessed streams while streaming data. In this paper, we present stream prefetcher design that can deal with both problems. Our stream prefetcher design utilizes stream waiting rooms to store not-recently-accessed streams. Stream waiting rooms help remove more off-chip misses. Using trace based simulations, our stream prefetcher design can remove 8% to 66% (on average 40%) and 17% to 63% (on average 39%) replacement and coherent read misses, respectively. Using cycle-accurate full-system simulation, our design gives speedups from 1.00 to 1.17 of princeton application repository for shared-memory computers (PARSEC) workloads running on a distributed shared memory system with the exception of dedup and swaptions workloads.