Abstract
We explain the counterintuitive observation that finding “good” pivots (close to the median of the array to be partitioned) may not improve performance of quicksort. Indeed, an intentionally skewed pivot improves performance. The reason is that while the instruction count decreases with the quality of the pivot, the likelihood that the direction of a branch is mispredicted also goes up. We analyze the effect of simple branch prediction schemes and measure the effects on real hardware.
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© 2006 Springer-Verlag Berlin Heidelberg
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Kaligosi, K., Sanders, P. (2006). How Branch Mispredictions Affect Quicksort. In: Azar, Y., Erlebach, T. (eds) Algorithms – ESA 2006. ESA 2006. Lecture Notes in Computer Science, vol 4168. Springer, Berlin, Heidelberg. https://doi.org/10.1007/11841036_69
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DOI: https://doi.org/10.1007/11841036_69
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-38875-3
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