task models

The INTERTWinE project has spent a lot of effort addressing interoperability challenges raised by task-based models. By rethinking parallelism in the paradigm of tasks, one reduces synchronisation and decouples the management of parallelism from computation.

This is really attractive but existing models typically rely on shared memory, where the programmer expresses input and output dependencies of tasks based upon variables, which in turn limits the technology to a single memory space – often a node of an HPC machine. So to then scale up beyond a single memory space we must combine a task model with distributed memory technology, such as MPI or GASPI, and this has been a focus for a number of activities in INTERTWinE.

Last month I attended a collaboration workshop in Japan between the Centre for Computational Sciences (CCS) at the University of Tsukuba and EPCC. I was talking about the INTERTWinE project, which addresses the problem of programming-model design and implementation for the Exascale, and specifically our work on the specification and implementation of a resource manager and directory/cache.