When Attention Meets Fast Recurrence: Training Language Models with Reduced Compute

Large language models have become increasingly difficult to train because of the required computation time and cost. In this work, we present SRU++, a recurrent unit with optional built-in attention that exhibits state-of-the-art modeling capacity and training efficiency. On standard language modeling benchmarks such as enwik8 and Wiki-103 datasets, our model obtains better perplexity and bits-per-character (bpc) while using 2.5x-10x less training time and cost compared to top-performing Transformer models. Our results reaffirm that attention is not all we need and can be complementary to other sequential modeling modules. Moreover, fast recurrence with little attention can be a leading model architecture.