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Main Authors: Zhao, Shiju, Hu, Junhao, Zheng, Jiaqi, Chen, Guihai
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2602.01519
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author Zhao, Shiju
Hu, Junhao
Zheng, Jiaqi
Chen, Guihai
author_facet Zhao, Shiju
Hu, Junhao
Zheng, Jiaqi
Chen, Guihai
contents The Key-Value (KV) cache of Large Language Models (LLMs) is prefix-based, making it highly inefficient for processing contexts retrieved in arbitrary order. Position-Independent Caching (PIC) has been proposed to enable KV reuse without positional constraints; however, existing approaches often incur substantial accuracy degradation, limiting their practical adoption. To address this issue, we propose native PIC by reintroducing the encoder to prevalent decoder-only LLMs and explicitly training it to support PIC. We further develop COMB, a PIC-aware caching system that integrates seamlessly with existing inference frameworks. Experimental results show that COMB reduces Time-to-First-Token (TTFT) by 51-94% and increases throughput by 3$\times$ with comparable accuracy. Furthermore, the quality improvement when using DeepSeek-V2-Lite-Chat demonstrates the applicability of COMB to other types of decoder-only LLMs. Our code is available at https://github.com/shijuzhao/Comb.
format Preprint
id arxiv_https___arxiv_org_abs_2602_01519
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle You Need an Encoder for Native Position-Independent Caching
Zhao, Shiju
Hu, Junhao
Zheng, Jiaqi
Chen, Guihai
Machine Learning
Artificial Intelligence
The Key-Value (KV) cache of Large Language Models (LLMs) is prefix-based, making it highly inefficient for processing contexts retrieved in arbitrary order. Position-Independent Caching (PIC) has been proposed to enable KV reuse without positional constraints; however, existing approaches often incur substantial accuracy degradation, limiting their practical adoption. To address this issue, we propose native PIC by reintroducing the encoder to prevalent decoder-only LLMs and explicitly training it to support PIC. We further develop COMB, a PIC-aware caching system that integrates seamlessly with existing inference frameworks. Experimental results show that COMB reduces Time-to-First-Token (TTFT) by 51-94% and increases throughput by 3$\times$ with comparable accuracy. Furthermore, the quality improvement when using DeepSeek-V2-Lite-Chat demonstrates the applicability of COMB to other types of decoder-only LLMs. Our code is available at https://github.com/shijuzhao/Comb.
title You Need an Encoder for Native Position-Independent Caching
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2602.01519