Using Predicated Execution to Improve the Performance of a Dynamically Scheduled Machine with Speculative Execution
| Autor: | Pohua P. Chang, Po-Yung Chang, Yale N. Patt, Eric Hao |
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| Rok vydání: | 1996 |
| Předmět: |
010302 applied physics
Computer science Branch Speculative execution Program transformation 02 engineering and technology Parallel computing Branch predictor 01 natural sciences 020202 computer hardware & architecture Theoretical Computer Science Scheduling (computing) 0103 physical sciences Theory of computation 0202 electrical engineering electronic engineering information engineering Speculative multithreading Hardware_CONTROLSTRUCTURESANDMICROPROGRAMMING Instruction-level parallelism Software Information Systems |
| Zdroj: | International Journal of Parallel Programming. 24:209-234 |
| ISSN: | 1573-7640 0885-7458 |
| Popis: | Conditional branches incur a severe performance penalty in wide-issue, deeply pipelined processors. Speculative execution(1, 2) and predicated execution(3---9) are two mechanisms that have been proposed for reducing this penalty. Speculative execution can completely eliminate the penalty associated with a particular branch, but requires accurate branch prediction to be effective. Predicated execution does not require accurate branch prediction to eliminate the branch penalty, but is not applicable to all branches and can increase the latencies within the program. This paper examines the performance benefit of using both mechanisms to reduce the branch execution penalty. Predicated execution is used to handle the hard-to-predict branches and speculative execution is used to handle the remaining branches. The hard-to-predict branches within the program are determined by profiling. We show that this approach can significantly reduce the branch execution penalty suffered by wide-issue processors. |
| Databáze: | OpenAIRE |
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