SAPCo Sort: Optimizing Degree-Ordering for Power-Law Graphs – ISPASS’22 (Poster)

2022 IEEE International Symposium on Performance Analysis of Systems and Software (ISPASS 2022)
May 22-24, 2022

DOI: 10.1109/ISPASS55109.2022.00015

Authors’ Copy (PDF)

While counting sort has a better complexity than comparison-based sorting algorithms, its parallelization suffers from high performance overhead and/or has a memory complexity that depends on the numbers of threads and elements.

In this paper, we explore the optimization of parallel counting sort for degree-ordering of real-world graphs with skewed degree distribution and we introduce the Structure-Aware Parallel Counting (SAPCo) Sort algorithm that leverages the skewed degree distribution to accelerate sorting.

The evaluation for graphs of up to 3.6 billion vertices shows that SAPCo sort is, on average, 1.7-33.5 times faster than state-of-the-art sorting algorithms such as counting sort, radix sort, and sample sort.

For a detailed explanation of the algorithms, please refer to Chapter 5 of the On Designing Structure-Aware High-Performance Graph Algorithms thesis.


  author={Koohi Esfahani, Mohsen and Kilpatrick, Peter and Vandierendonck, Hans},
  booktitle={2022 IEEE International Symposium on Performance Analysis of Systems and Software (ISPASS)}, 
  title={{SAPCo Sort}: Optimizing Degree-Ordering for Power-Law Graphs}, 
  publisher={IEEE Computer Society},

Code Availability
The source-code of SAPCo is available on LaganLighter Repository (alg1_sapco_sort.c and relabel.c files). A sample execution of this source code for “Twitter-MPI” graph is shown in the following:


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