Habanero-Scala: Async-Finish Programming in Scala

With the advent of the multicore era, it is clear that improvements in application performance will require parallelism. Programming models that utilize multiple cores offer promising directions for the future where core counts are expected to increase. There is, hence, a renewed interest in programming models that simplify the reasoning and writing of efficient parallel programs. In this paper, we present Habanero-Scala (HS) which implements a generic task parallel programming model that can be used to parallelize both regular and irregular applications. HS is a library extension of Scala and supports a hybrid programming model combining the previously developed Async/Finish Model (AFM) and Actor Model (AM). HS extends Scala’s actor-based concurrency model with creation of lightweight tasks embodied in async, future, and foreach constructs; termination detection using the finish construct; locality in the form of places; weak isolation using isolated blocks; and task coordination patterns using phasers, data-driven futures. HS offers a simpler parallel programming model compared to writing programs using threads and adds to the tools available for the programmer to aid in productivity and performance while developing parallel software.