ZoomR: Memory Efficient Reasoning through Multi-Granularity Key Value Retrieval

Fuente: arXiv
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Main Authors: Yang, David H., Zhu, Yuxuan, Amiri, Mohammad Mohammadi, Murugesan, Keerthiram, Pedapati, Tejaswini, Chaudhury, Subhajit, Chen, Pin-Yu
Format: Preprint
Published: 2026
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author Yang, David H.
Zhu, Yuxuan
Amiri, Mohammad Mohammadi
Murugesan, Keerthiram
Pedapati, Tejaswini
Chaudhury, Subhajit
Chen, Pin-Yu
author_facet Yang, David H.
Zhu, Yuxuan
Amiri, Mohammad Mohammadi
Murugesan, Keerthiram
Pedapati, Tejaswini
Chaudhury, Subhajit
Chen, Pin-Yu
contents Large language models (LLMs) have shown great performance on complex reasoning tasks but often require generating long intermediate thoughts before reaching a final answer. During generation, LLMs rely on a key-value (KV) cache for autoregressive decoding. However, the memory footprint of the KV cache grows with output length. Prior work on KV cache optimization mostly focus on compressing the long input context, while retaining the full KV cache for decoding. For tasks requiring long output generation, this leads to increased computational and memory costs. In this paper, we introduce ZoomR, a novel approach that enables LLMs to adaptively compress verbose reasoning thoughts into summaries and uses a dynamic KV cache selection policy that leverages these summaries while also strategically "zooming in" on fine-grained details. By using summary keys as a coarse-grained index during decoding, ZoomR uses the query to retrieve details for only the most important thoughts. This hierarchical strategy significantly reduces memory usage by avoiding full-cache attention at each step. Experiments across math and reasoning tasks show that our approach achieves competitive performance compared to baselines, while reducing inference memory requirements by more than $4\times$. These results demonstrate that a multi-granularity KV selection enables more memory efficient decoding, especially for long output generation.
format Preprint
id arxiv_https___arxiv_org_abs_2604_10898
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle ZoomR: Memory Efficient Reasoning through Multi-Granularity Key Value Retrieval
Yang, David H.
Zhu, Yuxuan
Amiri, Mohammad Mohammadi
Murugesan, Keerthiram
Pedapati, Tejaswini
Chaudhury, Subhajit
Chen, Pin-Yu
Machine Learning
Artificial Intelligence
Computation and Language
Large language models (LLMs) have shown great performance on complex reasoning tasks but often require generating long intermediate thoughts before reaching a final answer. During generation, LLMs rely on a key-value (KV) cache for autoregressive decoding. However, the memory footprint of the KV cache grows with output length. Prior work on KV cache optimization mostly focus on compressing the long input context, while retaining the full KV cache for decoding. For tasks requiring long output generation, this leads to increased computational and memory costs. In this paper, we introduce ZoomR, a novel approach that enables LLMs to adaptively compress verbose reasoning thoughts into summaries and uses a dynamic KV cache selection policy that leverages these summaries while also strategically "zooming in" on fine-grained details. By using summary keys as a coarse-grained index during decoding, ZoomR uses the query to retrieve details for only the most important thoughts. This hierarchical strategy significantly reduces memory usage by avoiding full-cache attention at each step. Experiments across math and reasoning tasks show that our approach achieves competitive performance compared to baselines, while reducing inference memory requirements by more than $4\times$. These results demonstrate that a multi-granularity KV selection enables more memory efficient decoding, especially for long output generation.
title ZoomR: Memory Efficient Reasoning through Multi-Granularity Key Value Retrieval
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2604.10898