Dynamic Frequency Boosting beyond Critical Path Delay

Abstract

This paper introduces an innovative post-implementation Dynamic Frequency Boosting (DFB) technique to release "hidden" performance margins of digital circuit designs currently suppressed by typical critical path constraint design flows, thus defining higher limits of operation speed. The proposed technique goes beyond state-of-the-art and exploits the data-driven path delay variability incorporating an innovative hardware clocking mechanism that detects in real-time the paths’ activation. In contrast to timing speculation, the operating speed is adjusted on the nominal path delay activation, succeeding an error-free acceleration. The proposed technique has been evaluated on three FPGA-based use cases carefully selected to exhibit differing domain characteristics, i.e i) a third party DNN inference accelerator IP for CIFAR-10 images achieving an average speedup of 18%, ii) a highly designer-optimized Optical Digital Equalizer design, in which DBF delivered a speedup of 50% and iii) a set of 5 synthetic designs examining high frequency (beyond 400 MHz) applications in FPGAs, achieving accelerations of 20-60% depending on the underlying path variability.