Distributed Event-Based Computing

As computing systems get larger in capability - a good thing - they also get larger in ways less desirable: cost, volume, power requirements and so on. Further, as the datastructures necessary to support large computations grow physically, the proportion of wallclock time spent communicating increases dramatically at the expense of the time spent calculating. This state of affairs is currently unacceptable and will only get worse as exa-scale machines move from the esoteric to the commonplace. As the unit cost of non-trivial cores continues tof all, one powerful approach is to build systems that have immense numbers of relatively small cores embedded (both geometrically and topologically) in a vast distributed network of stored state data: take the compute to the data, rather than the other way round. In this paper, we describe POETS - Partially Ordered Event Triggered Systems. This is a novel kind of computing architecture, built upon the neuromorphic concept that has inspired such machines as SpiNNaker[1,2] and BrainScaleS[3]. The central idea is that a problem is broken down into a large set of interacting devices, which communicate asynchronously via small, hardware brokered packets (the arrival of which is an event). The set of devices is the task graph. You cannot take a conventional codebase and port it to a POETS architecture; it is necessary to strip the application back to the underlying mathematics and reconstruct the algorithm in a manner sympathetic to the solution capabilities of the machine. However, for the class of problems for which thisapproach is suitable, POETS has already demonstrated solution speedups of afactor of 200 over conventional techniques.