RetentiveKV: State-Space Memory for Uncertainty-Aware Multimodal KV Cache Eviction

Sihao Liu, YuFan Xiong, Zhonghua Jiang, Zhaode Wang, Chengfei lv, Shengyu Zhang


Abstract
Multimodal Large Language Models face severe challenges in computational efficiency and memory consumption due to the substantial expansion of the visual KV cache when processing long visual contexts. Existing KV cache compression methods typically rely on the "persistence of importance" hypothesis to prune tokens. However, this approach proves fragile in multimodal settings due to two key issues: 1) Visual tokens display "deferred importance," initially exhibiting low salience but becoming pivotal during later decoding, which can lead to premature eviction. 2) Discrete pruning disrupts the inherent spatial continuity of visual cues. To address these challenges, we propose RetentiveKV, an entropy-driven KV cache optimization method that reformulates KV eviction from "discrete context truncation" to "continuous memory evolution" based on State Space Models. Our method leverages information entropy to quantify the information potential of low-attention tokens and integrates tokens scheduled for eviction into a continuous state space through entropy-guided state transitions, enabling their dynamic reactivation when semantic relevance arises during subsequent decoding. Extensive experiments on multimodal benchmarks demonstrate that RetentiveKV achieves 5.0 × KV cache compression and 1.5 × decoding acceleration.
Anthology ID:
2026.findings-acl.934
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
Findings
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Publisher:
Association for Computational Linguistics
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Pages:
18717–18727
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.934/
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Cite (ACL):
Sihao Liu, YuFan Xiong, Zhonghua Jiang, Zhaode Wang, Chengfei lv, and Shengyu Zhang. 2026. RetentiveKV: State-Space Memory for Uncertainty-Aware Multimodal KV Cache Eviction. In Findings of the Association for Computational Linguistics: ACL 2026, pages 18717–18727, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
RetentiveKV: State-Space Memory for Uncertainty-Aware Multimodal KV Cache Eviction (Liu et al., Findings 2026)
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