Efficient runahead threads

Abstract

Runahead Threads (RaT) is a promising solution that enables a thread to speculatively run ahead and prefetch data instead of stalling for a long-latency load in a simultaneous multithreading processor. With this capability, RaT can reduces resource monopolization due to memory-intensive threads and exploits memory-level parallelism, improving both system performance and single-thread performance. Unfortunately, the benefits of RaT come at the expense of increasing the number of executed instructions, which adversely affects its energy efficiency.