$A^3$: Attention-Aware Accurate KV Cache Fusion for Fast Large Language Model Serving

Fuente: arXiv
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Main Authors: Zhou, Yuechi, Su, Yi, Zhang, Jianxin, Li, Juntao, Xia, Qingrong, Wang, Zhefeng, Duan, Xinyu, Huai, Baoxing
Format: Preprint
Published: 2025
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author Zhou, Yuechi
Su, Yi
Zhang, Jianxin
Li, Juntao
Xia, Qingrong
Wang, Zhefeng
Duan, Xinyu
Huai, Baoxing
author_facet Zhou, Yuechi
Su, Yi
Zhang, Jianxin
Li, Juntao
Xia, Qingrong
Wang, Zhefeng
Duan, Xinyu
Huai, Baoxing
contents Large language models (LLMs) have demonstrated strong capabilities in processing long contexts, enabling them to tackle tasks involving long textual inputs such as multi-turn conversations, legal documents, or retrieved documents in Retrieval-Augmented Generation (RAG) systems. However, despite their ability to handle long sequences, the resulting decoding latency and memory overhead remain substantial, posing challenges for real-world deployment. Recent advances in KV Cache reuse have shown potential to mitigate these costs, but still suffer from notable performance degradation. To address this issue, we conduct an in-depth investigation of recomputation-based reuse methods and observe that the recomputed tokens often fail to align with the context segments most relevant to the question. This misalignment hinders proper updates to the critical contextual representations. Therefore, we propose the $\textbf{A}$ttention-$\textbf{A}$ware $\textbf{A}$ccurate KV Cache Fusion algorithm ($A^3$), which precomputes and selectively fuses the KV Cache of text chunks based on their relevance to the question, achieving accurate integration with minimal computational overhead. Extensive experiments on various benchmarks and LLMs demonstrate that $A^3$ achieves the best task performance compared to four baselines while reducing the time-to-first-token (TTFT) by 2$\times$.
format Preprint
id arxiv_https___arxiv_org_abs_2511_17560
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle $A^3$: Attention-Aware Accurate KV Cache Fusion for Fast Large Language Model Serving
Zhou, Yuechi
Su, Yi
Zhang, Jianxin
Li, Juntao
Xia, Qingrong
Wang, Zhefeng
Duan, Xinyu
Huai, Baoxing
Computation and Language
Artificial Intelligence
Large language models (LLMs) have demonstrated strong capabilities in processing long contexts, enabling them to tackle tasks involving long textual inputs such as multi-turn conversations, legal documents, or retrieved documents in Retrieval-Augmented Generation (RAG) systems. However, despite their ability to handle long sequences, the resulting decoding latency and memory overhead remain substantial, posing challenges for real-world deployment. Recent advances in KV Cache reuse have shown potential to mitigate these costs, but still suffer from notable performance degradation. To address this issue, we conduct an in-depth investigation of recomputation-based reuse methods and observe that the recomputed tokens often fail to align with the context segments most relevant to the question. This misalignment hinders proper updates to the critical contextual representations. Therefore, we propose the $\textbf{A}$ttention-$\textbf{A}$ware $\textbf{A}$ccurate KV Cache Fusion algorithm ($A^3$), which precomputes and selectively fuses the KV Cache of text chunks based on their relevance to the question, achieving accurate integration with minimal computational overhead. Extensive experiments on various benchmarks and LLMs demonstrate that $A^3$ achieves the best task performance compared to four baselines while reducing the time-to-first-token (TTFT) by 2$\times$.
title $A^3$: Attention-Aware Accurate KV Cache Fusion for Fast Large Language Model Serving
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2511.17560