LKV: End-to-End Learning of Head-wise Budgets and Token Selection for LLM KV Cache Eviction

Enshuai Zhou, Yifan Hao, Chao Wang, Rui Zhang, Di Huang, Jiaming Guo, Xing Hu, Zidong Du, Qi Guo, Yunji Chen


Abstract
Long-context inference in Large Language Models (LLMs) is bottlenecked by the linear growth of Key-Value (KV) cache memory. Existing KV cache compression paradigms are fundamentally limited by heuristics: heuristic budgeting relies on statistical priors rather than task objectives, causing resource misallocation, while heuristic selection relies on coupled query-key interactions or static inductive biases (e.g., attention sinks). To address this limitation, we introduce LKV (Learned KV Eviction), which formulates KV compression as an end-to-end differentiable optimization problem. LKV integrates LKV-H to learn task-optimized global budgets, and LKV-T to derive intrinsic KV importance without materializing attention matrices. This design bypasses heuristic proxies, strictly aligning compression with task objectives. Extensive evaluations demonstrate that LKV achieves state-of-the-art performance on both LongBench and RULER benchmarks at high compression rates. In particular, on LongBench, LKV achieves near-lossless performance with only 15% KV cache retention, and delivers up to 3.19x decoding throughput gains with negligible (~0.7%) overhead. Crucially, our analysis identifies learned budgeting as the dominant driver of fidelity, demonstrating that data-driven allocation is essential to overcome the limitations of hand-crafted heuristics.
Anthology ID:
2026.emnlp-main.1183
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
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Pages:
27116–27133
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URL:
https://aclanthology.org/2026.emnlp-main.1183/
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Cite (ACL):
Enshuai Zhou, Yifan Hao, Chao Wang, Rui Zhang, Di Huang, Jiaming Guo, Xing Hu, Zidong Du, Qi Guo, and Yunji Chen. 2026. LKV: End-to-End Learning of Head-wise Budgets and Token Selection for LLM KV Cache Eviction. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 27116–27133, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
LKV: End-to-End Learning of Head-wise Budgets and Token Selection for LLM KV Cache Eviction (Zhou et al., EMNLP 2026)
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https://aclanthology.org/2026.emnlp-main.1183.pdf