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Main Authors: Wang, Huizheng, Wang, Hongbin, Wei, Shaojun, Hu, Yang, Yin, Shouyi
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2512.06457
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author Wang, Huizheng
Wang, Hongbin
Wei, Shaojun
Hu, Yang
Yin, Shouyi
author_facet Wang, Huizheng
Wang, Hongbin
Wei, Shaojun
Hu, Yang
Yin, Shouyi
contents Attention-based large language models (LLMs) have transformed modern AI applications, but the quadratic cost of self-attention imposes significant compute and memory overhead. Dynamic sparsity (DS) attention mitigates this, yet its hardware efficiency is limited by the added prediction stage and the heavy memory traffic it entails. To address these limitations, this paper proposes BitStopper, a fine-grained algorithm-architecture co-design that operates without a sparsity predictor. First, a bit-serial enable stage fusion (BESF) mechanism is proposed to reuse and minimize the memory access by progressively terminating trivial tokens and merging the prediction stage into the execution stage. Second, a lightweight and adaptive token selection (LATS) strategy is developed to work in concert with the bit-level sparsity speculation. Third, a bit-level asynchronous processing (BAP) strategy is employed to improve compute utilization during the on-demand bit-grained memory fetching. Finally, an elaborate architecture is designed to translate the theoretical complexity reduction into practical performance improvement. Extensive evaluations demonstrate that, compared to state-of-the-art (SOTA) Transformer accelerators, BitStopper achieves 2.03x and 1.89x speedups over Sanger and SOFA, respectively, while delivering 2.4x and 2.1x improvements in energy efficiency.
format Preprint
id arxiv_https___arxiv_org_abs_2512_06457
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle BitStopper: An Efficient Transformer Attention Accelerator via Stage-fusion and Early Termination
Wang, Huizheng
Wang, Hongbin
Wei, Shaojun
Hu, Yang
Yin, Shouyi
Machine Learning
Signal Processing
Attention-based large language models (LLMs) have transformed modern AI applications, but the quadratic cost of self-attention imposes significant compute and memory overhead. Dynamic sparsity (DS) attention mitigates this, yet its hardware efficiency is limited by the added prediction stage and the heavy memory traffic it entails. To address these limitations, this paper proposes BitStopper, a fine-grained algorithm-architecture co-design that operates without a sparsity predictor. First, a bit-serial enable stage fusion (BESF) mechanism is proposed to reuse and minimize the memory access by progressively terminating trivial tokens and merging the prediction stage into the execution stage. Second, a lightweight and adaptive token selection (LATS) strategy is developed to work in concert with the bit-level sparsity speculation. Third, a bit-level asynchronous processing (BAP) strategy is employed to improve compute utilization during the on-demand bit-grained memory fetching. Finally, an elaborate architecture is designed to translate the theoretical complexity reduction into practical performance improvement. Extensive evaluations demonstrate that, compared to state-of-the-art (SOTA) Transformer accelerators, BitStopper achieves 2.03x and 1.89x speedups over Sanger and SOFA, respectively, while delivering 2.4x and 2.1x improvements in energy efficiency.
title BitStopper: An Efficient Transformer Attention Accelerator via Stage-fusion and Early Termination
topic Machine Learning
Signal Processing
url https://arxiv.org/abs/2512.06457