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Proceedings of the 22nd International Conference on Parallel Architectures and Compilation Techniques (2001)
Barcelona, Spain
Sept. 8, 2001 to Sept. 12, 2001
ISBN: 0-7695-1363-8
pp: 0097
Heather L. Hanson , The University of Texas at Austin
Daniel A. Jiménez , The University of Texas at Austin
Calvin Lin , The University of Texas at Austin
ABSTRACT
Abstract: We present a new method for branch prediction that encodes in the branch instruction a formula, chosen by profiling, that is used to perform history-based prediction. By using a special class of Boolean formulas, our encoding is extremely concise. By replacing the large tables found in current predictors with a small, fast circuit, our scheme is ideally suited to future technologies that will have large wire delays. In a projected 70 nm technology and an aggressive clock rate of about 5 GHz, an implementation of our method that uses an 8-bit formula encoding has a misprediction rate of 6.0%, 42% lower than that of the best gshare predictor implementable in that same technology. In today's technology, a 16-bit version of our predictor can replace bias bits in an 8K-entry agree predictor to achieve a 2.86% misprediction rate, which is slightly lower than the 2.93% misprediction rate of the Alpha 21264 hybrid predictor, even though the Alpha predictor has almost twice the hardware budget. Our predictor also consumes much less power than table-based predictors. This paper describes our predictor, explains our profiling algorithm, and presents experimental results using the SPEC 2000 integer benchmarks.
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CITATION
Heather L. Hanson, Daniel A. Jiménez, Calvin Lin, "Boolean Formula-Based Branch Prediction for Future Technologies", Proceedings of the 22nd International Conference on Parallel Architectures and Compilation Techniques, vol. 00, no. , pp. 0097, 2001, doi:10.1109/PACT.2001.953291
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