Iterative Synthesis Methods Estimating Programmable-Wire Congestion in a Dynamically Reconfigurable Processor

Abstract

Iterative synthesis methods for making aware of wire congestion are proposed for a multi-context dynamically reconfigurable processor (DRP) with a large number of processing elements (PEs) and programmable-wire connections. Although complex data-paths can be synthesized using the programmable-wire, its delay is long especially when wire connections are congested. We propose two iterative synthesis techniques between a high-level synthesizer (HLS) and the place & route tool to shorten the prolonged wire delay. First, we feed back wire delays for each context to a scheduler in the HLS. The experimental results showed that a critical-path delay was shorten by 21% on average for applications with timing closure problems. Second, we skip the routing and estimate wire delays based on the congestion. The synthesis time was shorten to 1/3 causing delay improvement rate degradation at two points on average.