Asynchronous simulated annealing on the placement problem: A beneficial race condition

Abstract

Race conditions, which occur when compute workers do not synchronise correctly, are considered undesirable in parallel computing, as they introduce often-unintended stochastic behaviour. This study presents an asynchronous parallel algorithm with a race condition, and demonstrates that it reaches a superior solution faster than the equivalent synchronous algorithm without the race condition. Specifically, a parallel simulated annealing algorithm that solves a graph mapping problem (placement) is used to explore this. This paper illustrates how problem size and degree of parallelism affects both the collision rate caused by the race condition, and convergence time. The asynchronous approach reaches a superior solution in half the time of the equivalent synchronous approach. The solver presented here can be applied to application deployment in distributed systems, and the concept can be applied to problems solvable by global optimisation methods, where fitness errors can be tolerated in exchange for faster execution.