Peregrine: A Flexible Hardware Accelerator for LSTM with Limited Synaptic Connection Patterns

In this paper, we present an integrated solution to design a high-performance LSTM accelerator. We propose a fast and flexible hardware architecture, named Peregrine, supported by a stack of innovations from algorithm to hardware design. Peregrine first minimizes the memory footprint by limiting the synaptic connection patterns within the LSTM network. Also, Peregrine provides parallel Huffman decoders with adaptive clocking to provide flexibility in dealing with a wide range of sparsity levels in the weight matrices. All these features are incorporated in a novel hardware architecture to maximize energy-efficiency. As a result, Peregrine improves performance by ~38% and energy-efficiency by ~33% in speech recognition compared to the state-of-the-art LSTM accelerator.