PARAG: PIM Architecture for Real-Time Acceleration of GCNs

Graph Convolutional Networks (GCNs) have successfully incorporated deep learning to graph structures for social network analysis, bio-informatics, etc. The execution pattern of GCNs is a hybrid of graph processing and neural networks which poses unique and significant challenges for hardware implementation. Graph processing involves a large amount of irregular memory access with little computation whereas processing of neural networks involves a large number of operations with regular memory access. Existing graph processing and neural network accelerators are therefore inefficient for computing GCNs. This paper presents Parag, processing in memory (PIM) architecture for GCN computation. It consists of customized logic with minuscule computing units called Neural Processing Elements (NPEs) interfaced to each bank of the DRAM to support parallel graph processing and neural network computation. It utilizes the massive internal parallelism of DRAM to accelerate the GCN execution with high energy efficiency. Simulation results for inference of GCN over standard datasets show a latency and energy reduction by three orders of magnitude over a CPU implementation. When compared to a state-of-the-art PIM architecture, PARAG achieves on an average 4x reduction in latency and 4.23x reduction in the energy-delay-product (EDP).