Power, Performance and Area Consequences of Multi-Context Support in CGRAs
Vimal Chacko, Jason Helge Anderson · 2021
A feature associated with coarse-grained reconfigurable arrays (CGRAs) is dynamic reconfigurability, wherein the CGRA supports multiple contexts. The multiple contexts form a set of configuration bitstreams that are loaded into the CGRA simultaneously and cycled through according to a schedule. Multi-context allows the CGRA hardware to be time-multiplexed: the logic blocks and interconnect can perform different functions according to the context selected in a given clock cycle. We consider how multi-context may be implemented at the circuit level, and evaluate three circuit implementations from the power, performance and area (PPA) perspectives. Results show that the choice of multi-context circuit implementation has an appreciable impact on the overall CGRA PPA. We also quantify the PPA overhead of the multi-context feature in CGRAs vs. a single-context device.