Parallel Subgraph Isomorphism on Multi-core Architectures: A Comparison of Four Strategies Based on Tree Search

Subgraph isomorphism is one of the most challenging problems on graph-based representations. Despite many efficient sequential algorithms have been proposed over the last decades, solving this problem on large graphs is still a time demanding task. For this reason, there is a recently growing interest in realizing effective parallel algorithms able to exploit at their best the modern multi-core architectures commonly available on servers and workstations. We propose a comparison of four parallel algorithms derived from the state-of-the-art sequential algorithm VF3-Light; two of them were presented in previous works, while the other two are introduced in this paper. In order to evaluate strong points and weaknesses of each algorithm, we performed a benchmark over six datasets of random large and dense graphs, both labelled and unlabelled, measuring memory usage, speed-up and efficiency. We also add a comparison with a different parallel algorithm, named Glasgow, that is not derived from VF3-Light.