DVAFS: Trading Computational Accuracy for Energy Through Dynamic-Voltage-Accuracy-Frequency-Scaling

Bert Moons, Roel Uytterhoeven, Wim Dehaene and Marian Verhelst
Department of Electrical Engineering - ESAT/MICAS, KU Leuven, Leuven, Belgium


Several applications in machine learning and machine-to-human interactions tolerate small deviations in their computations. Digital systems can exploit this fault-tolerance to increase their energy-efficiency, which is crucial in embedded applications. Hence, this paper introduces a new means of Approximate Computing: Dynamic-Voltage-Accuracy-Frequency-Scaling (DVAFS), a circuit-level technique enabling a dynamic trade-off of energy versus computational accuracy that outperforms other Approximate Computing techniques. The usage and applicability of DVAFS is illustrated in the context of Deep Neural Networks, the current state-of-the-art in advanced recognition. These networks are typically executed on CPU's or GPU's due to their high computational complexity, making their deployment on batteryconstrained platforms only possible through wireless connections with the cloud. This work shows how deep learning can be brought to IoT devices by running every layer of the network at its optimal computational accuracy. Finally, we demonstrate a DVAFS processor for Convolutional Neural Networks, achieving efficiencies of multiple TOPS/W.

Keywords: Deep learning, ConvNet, Convolutional neural network, CNN, Approximate computing, DVAFS, Dynamic-Voltage-Accuracy-Frequency-Scaling, Digital circuits.

Full Text (PDF)