Input-Aware Dynamic Timestep Spiking Neural Networks for Efficient In-Memory Computing

TL;DR

This paper introduces an input-aware dynamic timestep method for Spiking Neural Networks that adaptively determines the number of timesteps during inference, significantly reducing energy consumption and latency on in-memory computing hardware.

Contribution

The paper proposes a novel dynamic timestep algorithm for SNNs that adapts to input complexity, improving efficiency without sacrificing accuracy.

Findings

Achieves similar accuracy with 1.46 timesteps versus 4 in static SNNs.

Reduces energy-delay-product by 80%.

Incur negligible computational overhead.

Abstract

Spiking Neural Networks (SNNs) have recently attracted widespread research interest as an efficient alternative to traditional Artificial Neural Networks (ANNs) because of their capability to process sparse and binary spike information and avoid expensive multiplication operations. Although the efficiency of SNNs can be realized on the In-Memory Computing (IMC) architecture, we show that the energy cost and latency of SNNs scale linearly with the number of timesteps used on IMC hardware. Therefore, in order to maximize the efficiency of SNNs, we propose input-aware Dynamic Timestep SNN (DT-SNN), a novel algorithmic solution to dynamically determine the number of timesteps during inference on an input-dependent basis. By calculating the entropy of the accumulated output after each timestep, we can compare it to a predefined threshold and decide if the information processed at the current timestep is sufficient for a confident prediction. We deploy DT-SNN on an IMC architecture and show that it incurs negligible computational overhead. We demonstrate that our method only uses 1.46 average timesteps to achieve the accuracy of a 4-timestep static SNN while reducing the energy-delay-product by 80%.