Anaphase: a fine-grain thread decomposition scheme for speculative multithreading

Abstract

Industry is moving towards multi-core designs as we have hit the memory and power walls. Multi-core designs are very effective to exploit thread-level parallelism (TLP) but do not provide benefits when executing serial code (applications with low TLP, serial parts of a parallel application and legacy code). In this paper we propose Anaphase, a novel approach for speculative multithreading to improve single-thread performance in a multi-core design. The proposed technique is based on a graph partitioning technique which performs a decomposition of applications into speculative threads at instruction granularity. Moreover, the proposed technique leverages communications and pre-computation slices to deal with inter-thread dependences. Results presented in this paper show that this approach improves single-thread performance by 32% on average and up to 2.15x for some selected applications of the Spec2006 suite. In addition, the proposed technique outperforms by 21% on average schemes in which thread decomposition is performed at a coarser granularity.