ReRAM-Sharing: Fine-Grained Weight Sharing for ReRAM-Based Deep Neural Network Accelerator

Deep Neural Networks (DNNs) have gained a strong momentum across various applications in recent years. Meanwhile, they are compute- and memory-intensive as the deep layers induce massive matrix-multiplication operations. The Resistive Random Access Memory (ReRAM) can naturally carry out the matrix-multiplication in memory. Therefore, ReRAM-based accelerators are widely used for deploying DNN applications. Researchers strive to compress DNNs to accelerate DNNs on the ReRAM-based accelerators. However, the existing works focus on ReRAM-crossbar level compression. Such coarse-grained pruning lacks the flexibility for a higher compression rate. In this paper, we present our ReRAM-Sharing, a softwarehardware co-design scheme, to explore fined-grained weight sharing compression for ReRAM-based accelerators. Due to the limits of ADC bandwidth and ADC numbers, DNN computation on ReRAM crossbars is conducted in a smaller granularity, denoted as Operation Unit (OU). Motivated by this, we propose ReRAM-Sharing algorithm that applies weight-sharing on OU- level to exploit fine-grained sparsity. Our proposed ReRAM- Sharing reduces the redundancy of DNNs while maintaining the representation capability. Moreover, as the ReRAM-Sharing algorithm is orthogonal with the traditional pruning techniques, we can integrate them to shrink NN model size further. We then propose the ReRAM-Sharing architecture, which introduces the index table and adders to the traditional ReRAM-based accelerator, to support the ReRAM-Sharing algorithm. Experiment results show that our proposed ReRAM-Sharing achieves up to 59.39x and 14.47x compression ratio with negligible accuracy loss on CIFAR-10 and ImageNet datasets, respectively.