A Framework Exploiting Process Variability to Improve Energy Efficiency in FPGA Applications.

As technology node scales-down and process variability increases, the vendors impose even more conservative guard-bands to prevent potential malfunction of their microchips. However, this approach introduces considerable amounts of unexploited performance to individual chips, which can be harvested by developing novel customization tools. In the current work, we focus on the exploitation of process variability in modern FPGA chips to provide more energy efficient solutions. We propose a framework that i) generates variability maps characterizing the energy efficiency of commercial chips and ii) combines voltage and frequency scaling to limit the power dissipation of any given design for a given set of performance constraints. Experimental results on Zynq XC7Z020 28nm FPGAs show that the developed framework achieves up to 28.3% power reduction while maintaining the performance and functional integrity of realistic benchmarks. Moreover, by selecting the most efficient chip, we achieve up to 5.1% additional power savings.