User Experiences with a Chapel Implementation of UTS

Abstract—Chapel strives to combine programmability and performance in an architecture-independent way. We focus on programmability, and report on our ex-periences in implementing the Unbalanced Tree Search (UTS) benchmark with user-level task pools. Our con-tributions include a discussion on how to code objects that internally contain distributed arrays, as well as suggestions for language design such as support for locale-specific and task-specific data, scalar variable-based reduction, and the omission of const. The ambition of high-productivity parallel program-ming has led to the PGAS programming model and its concretization in a number of implementations. PGAS exposes a shared memory that is split into disjoint partitions, each comprising distinct computin