Enabling prefix sum parallelism pattern for recurrences with principled function reconstruction

Abstract

Much research work has been done to parallelize loops with recurrences over the last several decades. Recently, sampling-and-reconstruction method was proposed to parallelize a broad class of loops with recurrences in an automated fashion, with a practical runtime approach. Although the parallelized codes achieve linear scalability across multi-cores architectures, the sequential merge inherent to this method makes it not scalable on many core architectures, such as GPUs. At the same time, existing parallel merge approaches used for simple reduction loops cannot be directly and correctly applied to this method.