GeneSys: Enabling Continuous Learning through Neural Network Evolution in Hardware

Abstract

Modern deep learning systems rely on (a) a hand-tuned neural network topology, (b) massive amounts of labelled training data, and (c) extensive training over large-scale compute resources to build a system that can perform efficient image classification or speech recognition. Unfortunately, we are still far away from implementing adaptive general purpose intelligent systems which would need to learn autonomously in unknown environments and may not have access to some or any of these three components. Reinforcement learning and evolutionary algorithm (EA) based methods circumvent this problem by continuously interacting with the environment and updating the models based on obtained rewards. However, deploying these algorithms on ubiquitous autonomous agents at the edge (robots/drones) demands extremely high energy-efficiency due to (i) tight power and energy budgets, (ii) continuous / lifelong interaction with the environment, (iii) intermittent or no connectivity to the cloud to offloadheavy-weight processing. To address this need, we present Genesys, a HW-SW prototype of a EA-based learning system, that comprises of a closed loop learning engine called EvE and an inference engine called ADAM. EvE can evolve the topology and weights of neural networks completely in hardware for the task at hand, without requiring hand-optimization or backpropogation training. ADAM continuously interacts with the environment and is optimized for efficiently running the irregular neural networks generated by EvE. Genesys identifies and leverages multiple unique avenues of parallelism unique to EAs that we term gene-level parallelism, and population-level parallelism. We ran Genesys with a suite of environments from OpenAI gym and observed 2--5 orders of magnitude higher energy-efficiency over state-of-the-art embedded and desktop CPU and GPU systems.