Prophet: A Speculative Multi-threading Execution Model with Architectural Support Based on CMP

Abstract: Speculative multi-threading (SpMT) has been proposed as a perspective method to exploit Chip Multiprocessors (CMP) hardware potential. It is a thread level speculation (TLS) model mainly depending on software and hardware co-design. This paper researches speculative thread-level parallelism of general purpose programs and a speculative multi-threading execution model called Prophet is presented. The architectural support for Prophet execution model is designed based on CMP. In Prophet the inter-thread data dependency are predicted by pre-computation slice (p-slice) to reduce RAW violation. Prophet multi-versioning Cache system along with thread state control mechanism in architectural support are utilized for buffering the speculative data, and a snooping bus based cache coherence protocol is used to detect data dependence violation. The simulation-based evaluation shows that the Prophet system could achieve significant speedup for general-purpose programs.