Software decomposition for multicore architectures

Current multicore processors attempt to optimize consumer experience via task partitioning and concurrent execution of these (sub)tasks on the cores. Conversion of sequential code to parallel and concurrent code is neither easy, nor feasible with current methodologies. We have developed a mapping process that synergistically uses top-down and bottom-up methodologies. This process is amenable to automation. We use bottom-up analysis to determine decomposability and estimate computation and communication metrics. The outcome is a set of proposals for software decomposition. We then build abstract concurrent models that map these decomposed (abstract) software modules onto candidate multicore architectures; this resolves concurrency issues. We then perform a system level simulation to estimate concurrency gain and/or cost, and QOS (Qualify-of-Service) metrics. Different architectural combinations yield different QOS metrics; the requisite system architecture may then be chosen. We applied this 'middle-out' methodology to optimally map a digital camera application onto a processor with four cores.