Among the programming models for parallel and distributed computing, one can identify two important families. The programming models adapted to data-parallelism, where a set of coordinated processes perform a computation by splitting the input data; and coordination languages able to express complex coordination patterns and rich interactions between processing entities. This article takes two successful programming models belonging to the two categories and puts them together into an effective programming model. More precisely, we investigate the use of active objects to coordinate BSP processes. We choose two paradigms that both enforce the absence of data-races, one of the major sources of error in parallel programming. This article explains why we believe such a model is interesting and provides a formal semantics integrating the notions of the two programming paradigms in a coherent and effective manner.

This paper defines distributed futures, a construct that provides at the same time a data container similar to a distributed vector, and a single synchronization entity that behaves similarly to a standard future. This simple construct makes it easy to program a composition, in a task-parallel way, of several massively data-parallel tasks. The approach is implemented and evaluated in the context of a bulk synchronous parallel (BSP) active object framework. CCS CONCEPTS• Software and its engineering → Parallel programming languages; Concurrent programming structures.

Testing parallel applications on a large number of processors is often impractical. Not only does it require access to scarce compute resources, but tracking down defects with the available debugging tools can often be very time consuming. Highly parallel codes should be testable on one processor at a time, so that a developer’s workstation is sufficient for executing and debugging test cases on millions of processes. Thanks to its supersteps, Bulk Synchronous Parallel programs are well suited for this kind of testing. This paper presents a mocking library for BSPlib which enables testing of fast and complex parallel algorithms at scale.

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