ASP: Adaptive Semantic Preservation for Context Compression

Shaoshen Chen, Peiyang Li, Jiaming Mu, Guixiong Chen, Fengting Li, Chao Feng


Abstract
Context compression has emerged as a vital approach to mitigate both performance degradation and resource consumption for large language models (LLMs) in long context scenarios. Current state-of-the-art methods allocate the compression budget at fixed-size block granularity, either uniformly or with adaptation across blocks. Both strategies fragment sentence-level semantic units and overlook the relevance variation within each block. In this paper, we propose the Adaptive Semantic Preservation (ASP) compressor, built on two innovations: (1) To preserve semantic units, our Semantic-Preserving Segmentation partitions context along natural sentence boundaries while maintaining the morphological atomicity of words. (2) To prioritize critical information, our task-aware Adaptive Budget Allocation dynamically assigns compression budget based on each sentence’s informational salience for the task instruction. Extensive experiments across diverse long-context scenarios show that ASP outperforms strong task-aware and task-agnostic compression baselines on both Llama-3-8B-Instruct and Qwen-2.5-7B-Instruct. In particular, ASP delivers stronger robustness compared with other baselines even at the extreme 16× high compression ratio.
Anthology ID:
2026.findings-emnlp.1084
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
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SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
22950–22967
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URL:
https://aclanthology.org/2026.findings-emnlp.1084/
DOI:
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Cite (ACL):
Shaoshen Chen, Peiyang Li, Jiaming Mu, Guixiong Chen, Fengting Li, and Chao Feng. 2026. ASP: Adaptive Semantic Preservation for Context Compression. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 22950–22967, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
ASP: Adaptive Semantic Preservation for Context Compression (Chen et al., Findings 2026)
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https://aclanthology.org/2026.findings-emnlp.1084.pdf