Bypassing of Channels in Eden

We describe automatic bypassing, an optimization of Eden’s implementation to reduce the number of messages and/or threads at runtime. Eden [BLOP97] extends the lazy functional language Haskell with a set of coordination features, aimed to express parallel algorithms. These include process abstractions (or process schemes) and process instantiations (or applications of a process scheme to actual inputs). When a new process is instantiated, their input and output channels are connected to its parent process. This implies that, in principle, only tree–like process topologies can be created. But the aimed topology may not be tree–like (e.g. pipelines, grids, etc.). It is desirable to be able to connect every producer to its actual consumer, trying to avoid the intermediate processes frequently used only to set up the topology. The strategy consists of a combination of compile time analysis and runtime support. Both are explained in detail. Also, the savings expected with the proposed strategy are commented. Work partially supported by the spanish projects CAM-06T/033/96 and CICYT-TIC97-0672.