MITra: Populating Graph Traversal Algorithms

We demonstrate MITra, a system for synthesizing Multi-Instance graph Traversal algorithms that traverse from multiple source vertices simultaneously over a single thread. Underlying MITra is an abstraction that expresses traversal logic via arithmetic operations over a numeric runtime property called vertex ranks, and separates it from computation logic. Based on this, Mitra implements an interface that allows users to express traversals by declaring vertex ranks and specify computation logic by “plugging in” an edge function adopted from classic single-instance algorithms. It synthesizes multi-instance traversal algorithms from declared vertex ranks and edge functions, automatically sharing computation across instances and benefiting from SIMD. We demonstrate its expressiveness, ease-of-use and performance for supporting multi-instance graph traversal computations. We also demonstrate a use case of MITra for shortest-path tree (SPT) computation over data center IP networks.