Task-based programming in COMPSs to converge from HPC to big data

Task-based programming has proven to be a suitable model for high-performance computing (HPC) applications. Different implementations have been good demonstrators of this fact, and have promoted the acceptance of task-based programming in the OpenMP standard. Furthermore, in recent years, Apache Spark has gained wide popularity in business and research environments as a programming model for addressing emerging Big-Data problems. COMP Superscalar (COMPSs) is a task-based environment that tackles distributed computing (including Clouds), and is a good alternative for a task-based programming model for Big Data applications. This paper describes why we consider that task-based programming models are a good approach for Big Data applications. The paper includes a comparison of Spark and COMPSs in terms of architecture, programming model and performance. It focuses on the differences that both frameworks have in structural terms, on their programmability interface, and in terms of their efficiency by means of three widely known benchmarking kernels: Wordcount, Kmeans and Terasort. These kernels enable the evaluation of the more important functionalities of both programming models and analyse different workflows and conditions. The main results achieved from this comparison are: (1) COMPSs is able to extract the inherent parallelism from the user code with minimal coding effort as opposed to Spark, which requires the existing algorithms to be adapted and rewritten by explicitly using their pre-defined functions; (2) it is an improvement in terms of performance when compared with Spark, and (3) COMPSs has shown to scale better than Spark in most cases. Finally, we discuss the advantages and disadvantages of both frameworks, highlighting the differences that make them unique, thereby helping to choose the right framework for each particular objective. Keywords-Programming models; Distributed computing; Framework comparison; Big Data programming;