Kwai Summary Attention

Chenglong Chu, Hao Peng, Hui Wang, Jiangxia Cao, Lu Ren, Zhiyuan Liang, Ziqi Wang, Hongtao Cheng, Yi Su, Xinchen Luo, Jian Liang, Ruiming Tang, Guorui Zhou, Han Li


Abstract
Long-context capability has become increasingly critical for next-generation Large Language Models (LLMs). However, the quadratic time complexity of standard softmax attention introduces substantial computation and memory overhead as sequence length grows, limiting the scalability of LLMs in long-context scenarios. Beyond existing approaches such as linear recurrent architectures and KV-cache compression methods, we propose Kwai Summary Attention (KSA), a novel attention mechanism that reduces sequence modeling cost by compressing historical contexts into learnable summary tokens. Specifically, summary tokens are periodically inserted into the input sequence and interleaved with text tokens, partitioning the sequence into distinct chunks while enabling text tokens and summary tokens to operate under different attention scopes. This design preserves dense local expressiveness through full attention among neighboring text tokens, while modeling long-range dependencies efficiently via summary tokens. Empirical results demonstrate that hybrid-KSA consistently outperforms existing hybrid attention variants in long-context modeling. Moreover, KSA is fully orthogonal to GQA and MLA during inference, and combining KSA with these methods achieves up to 8x KV-cache compression while preserving model performance.
Anthology ID:
2026.findings-emnlp.1953
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
41635–41655
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1953/
DOI:
Bibkey:
Cite (ACL):
Chenglong Chu, Hao Peng, Hui Wang, Jiangxia Cao, Lu Ren, Zhiyuan Liang, Ziqi Wang, Hongtao Cheng, Yi Su, Xinchen Luo, Jian Liang, Ruiming Tang, Guorui Zhou, and Han Li. 2026. Kwai Summary Attention. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 41635–41655, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Kwai Summary Attention (Chu et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1953.pdf