VisCache: Visual KV Cache Pruning for Efficient Vision Large Language Model Inference

Lyuke Wang, Zhuo Li, Guangxu Zhu


Abstract
While Vision Large Language Models (VLLMs) have achieved remarkable success in multimodal reasoning, their long-context inference remains prohibitively expensive due to the massive computation and memory overhead of visual Key-Value (KV) caches. Existing KV compression methods often apply uniform pruning across visual tokens and layers, leading to substantial information loss and degraded performance. To address this challenge, we propose **VisCache**, a plug-and-play framework for coarse-to-fine **Vis**ual KV **Cache** pruning without training, which consists of two synergistic stages. First, a lightweight VLM filters temporal redundancy by selectively forwarding semantically informative keyframes. Second, we introduce PruneKV, a surgical KV compression algorithm tailored to the attention dynamics of VLLMs. Unlike rigid pruning strategies, PruneKV adopts a parabolic layer-wise budget allocation together with an asymmetric update mechanism that selectively prunes keys while fusing values, thereby preserving critical contextual information. Extensive experiments demonstrate that VisCache substantially improves inference efficiency, achieving up to 2.35× speedup and significant memory reduction while maintaining competitive performance with only 19–28% KV cache retention. VisCache consistently outperforms existing baselines, establishing a new Pareto frontier between efficiency and performance for long-context VLLM inference.
Anthology ID:
2026.emnlp-main.1196
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
27385–27406
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1196/
DOI:
Bibkey:
Cite (ACL):
Lyuke Wang, Zhuo Li, and Guangxu Zhu. 2026. VisCache: Visual KV Cache Pruning for Efficient Vision Large Language Model Inference. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 27385–27406, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
VisCache: Visual KV Cache Pruning for Efficient Vision Large Language Model Inference (Wang et al., EMNLP 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.emnlp-main.1196.pdf