Automating vectorized distributed graph computation

Multi-instance graph algorithms interleave the evaluation of multiple instances of the same algorithm with different inputs over the same graph. They have been shown to be significantly faster than traditional serial and batch evaluation, by sharing computation across instances. However, writing correct multi-instance algorithms is challenging; and in this work, we describe AutoMI, a framework for automatically converting vertex-centric graph algorithms into their vectorized multi-instance versions. We also develop an algebraic characterization of algorithms that can benefit best from multi-instance computation with simpler and faster streamlined vectorization. This allows users to decide when to use such optimization and instruct AutoMI to make the best use of SIMD vectorization. Using 6 real-life graphs, we show that AutoMI-converted multi-instance algorithms are 9.6 to 29.5 times faster than serial evaluation, 7.1 to 26.4 times faster than batch evaluation, and are even 2.6 to 4.6 times faster than existing highly optimized handcrafted multi-instance algorithms without vectorization.