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Main Authors: Qiu, Junxiang, Wang, Shuo, Chen, Zhengsu, Zhang, Hengheng, Lu, Jinda, Li, Changcheng, Tian, Qi
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2601.02819
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author Qiu, Junxiang
Wang, Shuo
Chen, Zhengsu
Zhang, Hengheng
Lu, Jinda
Li, Changcheng
Tian, Qi
author_facet Qiu, Junxiang
Wang, Shuo
Chen, Zhengsu
Zhang, Hengheng
Lu, Jinda
Li, Changcheng
Tian, Qi
contents Attention serves as the fundamental mechanism for long-context modeling in large language models (LLMs), yet dense attention becomes structurally prohibitive for long sequences due to its quadratic complexity. Consequently, sparse attention has received increasing attention as a scalable alternative. However, existing sparse attention methods rely on coarse-grained semantic representations during block selection, which blur intra-block semantic boundaries and lead to the loss of critical information. To address this issue, we propose \textbf{P}unctuation-aware \textbf{H}ybrid \textbf{S}parse \textbf{A}ttention \textbf{(PHSA)}, a natively trainable sparse attention framework that leverages punctuation tokens as semantic boundary anchors. Specifically, (1) we design a dual-branch aggregation mechanism that fuses global semantic representations with punctuation-enhanced boundary features, preserving the core semantic structure while introducing almost no additional computational overhead; (2) we introduce an extreme-sparsity-adaptive training and inference strategy that stabilizes model behavior under very low token activation ratios; Extensive experiments on general benchmarks and long-context evaluations demonstrate that PHSA consistently outperforms dense attention and state-of-the-art sparse attention baselines, including InfLLM v2. Specifically, for the 0.6B-parameter model with 32k-token input sequences, PHSA can reduce the information loss by 10.8\% at a sparsity ratio of 97.3\%.
format Preprint
id arxiv_https___arxiv_org_abs_2601_02819
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Punctuation-aware Hybrid Trainable Sparse Attention for Large Language Models
Qiu, Junxiang
Wang, Shuo
Chen, Zhengsu
Zhang, Hengheng
Lu, Jinda
Li, Changcheng
Tian, Qi
Computation and Language
Attention serves as the fundamental mechanism for long-context modeling in large language models (LLMs), yet dense attention becomes structurally prohibitive for long sequences due to its quadratic complexity. Consequently, sparse attention has received increasing attention as a scalable alternative. However, existing sparse attention methods rely on coarse-grained semantic representations during block selection, which blur intra-block semantic boundaries and lead to the loss of critical information. To address this issue, we propose \textbf{P}unctuation-aware \textbf{H}ybrid \textbf{S}parse \textbf{A}ttention \textbf{(PHSA)}, a natively trainable sparse attention framework that leverages punctuation tokens as semantic boundary anchors. Specifically, (1) we design a dual-branch aggregation mechanism that fuses global semantic representations with punctuation-enhanced boundary features, preserving the core semantic structure while introducing almost no additional computational overhead; (2) we introduce an extreme-sparsity-adaptive training and inference strategy that stabilizes model behavior under very low token activation ratios; Extensive experiments on general benchmarks and long-context evaluations demonstrate that PHSA consistently outperforms dense attention and state-of-the-art sparse attention baselines, including InfLLM v2. Specifically, for the 0.6B-parameter model with 32k-token input sequences, PHSA can reduce the information loss by 10.8\% at a sparsity ratio of 97.3\%.
title Punctuation-aware Hybrid Trainable Sparse Attention for Large Language Models
topic Computation and Language
url https://arxiv.org/abs/2601.02819