Runahead Threads to Improve SMT Performance

In this paper, the authors propose Runahead Threads (RaT) as a valuable solution for both reducing resource contention and exploiting memory-level parallelism in Simultaneous Multithreaded (SMT) processors. The technique converts a resource intensive memory-bound thread to a speculative light thread under long-latency blocking memory operations. These speculative threads prefetch data and instructions with minimal resources, reducing critical resource conflicts between threads. They compare an SMT architecture using RaT to both state-of-the-art static fetch policies and dynamic resource control policies.