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arXiv · 1008.2849

Faster Radix Sort via Virtual Memory and Write-Combining

Jan Wassenberg·Peter Sanders
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Abstract

Sorting algorithms are the deciding factor for the performance of common operations such as removal of duplicates or database sort-merge joins. This work focuses on 32-bit integer keys, optionally paired with a 32-bit value. We present a fast radix sorting algorithm that builds upon a microarchitecture-aware variant of counting sort. Taking advantage of virtual memory and making use of write-combining yields a per-pass throughput corresponding to at least 88 % of the system's peak memory bandwidth. Our implementation outperforms Intel's recently published radix sort by a factor of 1.5. It also compares favorably to the reported performance of an algorithm for Fermi GPUs when data-transfer overhead is included. These results indicate that scalar, bandwidth-sensitive sorting algorithms remain competitive on current architectures. Various other memory-intensive applications can benefit from the techniques described herein.

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Jan Wassenberg, Peter Sanders. 2010-09-06. Faster Radix Sort via Virtual Memory and Write-Combining. https://arxiv.org/abs/1008.2849

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