Wavefront template implementation based on the task programming model

A particular characteristic of the parallel wavefront pattern is the multi-dimensional streaming nature of the computations that must obey a dependence pattern. Modern task based programming libraries like TBB (Threading Building Blocks) provide interesting features to improve the scalability of this kind of codes but at a cost of leaving some low level task management details to the programmer. We discuss such low level task management issues and incorporate them into a high level TBB based template that we present in this paper. The goal of the template is to improve the programmer’s productivity to allow a non expert user to easily code complex wavefront problems without worrying about task creation, synchronization or scheduling mechanisms. In our template, the user only has to specify a definition file with the wavefront dependence pattern and the function that each task has to execute. In addition, we describe our experience with the TBB based template when coding four complex real wavefront problems, finding that the programming effort of the user is reduced from 25% to 50% at a cost of increasing the overhead below 5% when compared with manual TBB implementations of the same problem.