RecurFormer: Not All Transformer Heads Need Self-Attention
Keywords: Transformer, Large Language Models, Recurrent Neural Networks
TL;DR: This paper introduces RecurFormer, an architecture that replaces attention heads affected by the recency aware with linear RNNs, reducing cache size while maintaining text generation quality.
Abstract: Transformer-based large language models (LLMs) excel in modeling complex language patterns but face significant computational costs during inference, especially with long inputs due to the attention mechanism's memory overhead. We observe that certain attention heads exhibit a distribution where the attention weights concentrate on tokens near the query token, termed as recency aware, which focuses on local and short-range dependencies. Leveraging this insight, we propose RecurFormer, a novel architecture that replaces these attention heads with linear recurrent neural networks (RNNs), specifically the Mamba architecture. This replacement reduces the cache size without evicting tokens, thus maintaining generation quality. RecurFormer retains the ability to model long-range dependencies through the remaining attention heads and allows for reusing pre-trained Transformer-based LLMs weights with continual training. Experiments demonstrate that RecurFormer matches the original model's performance while significantly enhancing inference efficiency. Our approach provides a practical solution to the computational challenges of Transformer-based LLMs inference, making it highly attractive for tasks involving long inputs.
Primary Area: foundation or frontier models, including LLMs
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Submission Number: 7043
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