IDaTPA: importance degree based thread partitioning approach in thread level speculation

Abstract

As an auto-parallelization technique with the level of thread on multi-core, Thread-Level Speculation (TLS) which is also called Speculative Multithreading (SpMT), partitions programs into multiple threads and speculatively executes them under conditions of ambiguous data and control dependence. Thread partitioning approach plays a key role to the performance enhancement in TLS. The existing heuristic rules-based approach (HR-based approach) which is an one-size-fits-all strategy, can not guarantee to achieve the satisfied thread partitioning. In this paper, an importance degree based thread partitioning approach (IDaTPA) is proposed to realize the partition of irregular programs into multithreads. IDaTPA implements biasing partitioning for every procedure with a machine learning method. It mainly includes: constructing sample set, expression of knowledge, calculation of similarity, prediction model and the partition of the irregular programs is performed by the prediction model. Using IDaTPA, the subprocedures in unseen irregular programs can obtain their satisfied partition. On a generic SpMT processor (called Prophet) to perform the performance evaluation for multithreaded programs, the IDaTPA is evaluated and averagely delivers a speedup of 1.80 upon a 4-core processor. Furthermore, in order to obtain the portability evaluation of IDaTPA, we port IDaTPA to 8-core processor and obtain a speedup of 2.82 on average. Experiment results show that IDaTPA obtains a significant speedup increasement and Olden benchmarks respectively deliver a 5.75% performance improvement on 4-core and a 6.32% performance improvement on 8-core, and SPEC2020 benchmarks obtain a 38.20% performance improvement than the conventional HR-based approach.