Accelerating LLM Inference via Dynamic KV Cache Placement in Heterogeneous Memory System

Fuente: arXiv
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Autores principales: Fang, Yunhua, Xie, Rui, Haq, Asad Ul, Ma, Linsen, Maghraoui, Kaoutar El, Wang, Naigang, Wang, Meng, Liu, Liu, Zhang, Tong
Formato: Preprint
Publicado: 2025
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author Fang, Yunhua
Xie, Rui
Haq, Asad Ul
Ma, Linsen
Maghraoui, Kaoutar El
Wang, Naigang
Wang, Meng
Liu, Liu
Zhang, Tong
author_facet Fang, Yunhua
Xie, Rui
Haq, Asad Ul
Ma, Linsen
Maghraoui, Kaoutar El
Wang, Naigang
Wang, Meng
Liu, Liu
Zhang, Tong
contents Large Language Model (LLM) inference is increasingly constrained by memory bandwidth, with frequent access to the key-value (KV) cache dominating data movement. While attention sparsity reduces some memory traffic, the relevance of past tokens varies over time, requiring the full KV cache to remain accessible and sustaining pressure on both bandwidth and capacity. With advances in interconnects such as NVLink and LPDDR5X, modern AI hardware now integrates high-bandwidth memory (HBM) with high-speed off-package DRAM, making heterogeneous memory systems a practical solution. This work investigates dynamic KV cache placement across such systems to maximize aggregated bandwidth utilization under capacity constraints. Rather than proposing a specific scheduling policy, we formulate the placement problem mathematically and derive a theoretical upper bound, revealing substantial headroom for runtime optimization. To our knowledge, this is the first formal treatment of dynamic KV cache scheduling in heterogeneous memory systems for LLM inference.
format Preprint
id arxiv_https___arxiv_org_abs_2508_13231
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Accelerating LLM Inference via Dynamic KV Cache Placement in Heterogeneous Memory System
Fang, Yunhua
Xie, Rui
Haq, Asad Ul
Ma, Linsen
Maghraoui, Kaoutar El
Wang, Naigang
Wang, Meng
Liu, Liu
Zhang, Tong
Hardware Architecture
Artificial Intelligence
Performance
Large Language Model (LLM) inference is increasingly constrained by memory bandwidth, with frequent access to the key-value (KV) cache dominating data movement. While attention sparsity reduces some memory traffic, the relevance of past tokens varies over time, requiring the full KV cache to remain accessible and sustaining pressure on both bandwidth and capacity. With advances in interconnects such as NVLink and LPDDR5X, modern AI hardware now integrates high-bandwidth memory (HBM) with high-speed off-package DRAM, making heterogeneous memory systems a practical solution. This work investigates dynamic KV cache placement across such systems to maximize aggregated bandwidth utilization under capacity constraints. Rather than proposing a specific scheduling policy, we formulate the placement problem mathematically and derive a theoretical upper bound, revealing substantial headroom for runtime optimization. To our knowledge, this is the first formal treatment of dynamic KV cache scheduling in heterogeneous memory systems for LLM inference.
title Accelerating LLM Inference via Dynamic KV Cache Placement in Heterogeneous Memory System
topic Hardware Architecture
Artificial Intelligence
Performance
url https://arxiv.org/abs/2508.13231