Paired ROBs: A Cost-Effective Reorder Buffer Sharing Strategy for SMT Processors

An important design issue of SMT processors is to find proper sharing strategies of resources among threads. This paper proposes a ROB sharing strategy, called paired ROB, that considers the fact that task parallelism is not always available to fully utilize resources of multithreaded processors. To this aim, an evaluation methodology is proposed and used for the experiments, which analyzes performance under different degrees of parallelism. Results show that paired ROBs are a cost-effective strategy that provides better performance than private ROBs for low task parallelism, whereas it incurs slight performance losses for high task parallelism.