Beyond synchronous: New techniques for external-memory graph connectivity and minimum spanning forest

Abstract

GraphChi [16] is a recent high-performance system for external memory (disk-based) graph computations. It uses the Parallel Sliding Windows (PSW) algorithm which is based on the so-called Gauss-Seidel type of iterative computation, in which updates to values are immediately visible within the iteration. In contrast, previous external memory graph algorithms are based on the synchronous model where computation can only observe values from previous iterations. In this work, we study implementations of connected components and minimum spanning forest on PSW and show that they have a competitive I/O bound of O(sort(E)log(V/M)) and also work well in practice. We also show that our MSF implementation is competitive with a specialized algorithm proposed by Dementiev et al. [10] while being much simpler. © 2014 Springer International Publishing.