Second - level Instruction Cache Thread Processing Unit Thread Processing Unit Thread Processing Unit Instruction Cache First - level First - level First - level Instruction Cache Instruction Cache Execution

This paper presents a new parallelization model, called coarse-grained thread pipelining, for exploiting speculative coarse-grained parallelism from general-purpose application programs in shared-memory multiprocessor systems. This parallelization model, which is based on the ne-grained thread pipelining model proposed for the superthreaded architecture 11, 12], allows concurrent execution of loop iterations in a pipelined fashion with run-time data-dependence checking and control speculation. The speculative execution combined with the run-time dependence checking allows the parallelization of a variety of program constructs that cannot be parallelized with existing run-time parallelization algorithms. The pipelined execution of loop iterations in this new technique results in lower parallelization overhead than in other existing techniques. We evaluated the performance of this new model using some real applications and a synthetic benchmark. These experiments show that programs with a suuciently large grain size compared to the parallelization overhead obtain signiicant speedup using this model. The results from the synthetic benchmark provide a means for estimating the performance that can be obtained from application programs that will be parallelized with this model. The library routines developed for this thread pipelining model are also useful for evaluating the correctness of the codes generated by the superthreaded compiler and in debugging and verifying the simulator for the superthreaded processor.