KV-RM: Regularizing KV-Cache Movement for Static-Graph LLM Serving

Fuente: arXiv
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Autori principali: Zhong, Zhiqing, Ye, Zhijing, Zhang, Jian, Zheng, Weijian, Sun, Bolun, Yu, Xiaodong
Natura: Preprint
Pubblicazione: 2026
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author Zhong, Zhiqing
Ye, Zhijing
Zhang, Jian
Zheng, Weijian
Sun, Bolun
Yu, Xiaodong
author_facet Zhong, Zhiqing
Ye, Zhijing
Zhang, Jian
Zheng, Weijian
Sun, Bolun
Yu, Xiaodong
contents Static-graph LLM decoders provide predictable launches, fixed tensor shapes, and low submission overhead, but online decoding exposes highly irregular KV-cache behavior: request lengths differ, EOS events arrive asynchronously, and logical histories fragment over time. Dynamic runtimes recover flexibility through paged KV management and step-level scheduling, while static-graph executors often over-reserve memory and suffer burst-time latency outliers. This paper studies whether much of this variability can be absorbed below a fixed decode interface. We present KV-RM, a runtime design that regularizes KV-cache movement beneath a static-graph LLM decoder. KV-RM decouples logical KV histories from physical storage, tracks active KV state through a block pager, and materializes each decode step through a single committed descriptor. A merge-staged transport path coalesces non-contiguous KV mappings into a small number of large transfer groups before a fixed-shape attention kernel consumes them. Optional bounded far-history summaries can be enabled under the same interface, but the core design does not depend on them. On a 2-GPU NVIDIA A100 node, KV-RM improves mixed-length decoding throughput and tail latency relative to a static-graph baseline, reduces reserved KV memory across workload families, and removes severe burst-time latency spikes under production-trace replay. These results suggest that KV-cache movement, rather than kernel shape, can be an effective boundary for recovering runtime flexibility in static-graph LLM serving.
format Preprint
id arxiv_https___arxiv_org_abs_2605_09735
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle KV-RM: Regularizing KV-Cache Movement for Static-Graph LLM Serving
Zhong, Zhiqing
Ye, Zhijing
Zhang, Jian
Zheng, Weijian
Sun, Bolun
Yu, Xiaodong
Hardware Architecture
Artificial Intelligence
Distributed, Parallel, and Cluster Computing
Operating Systems
Primary category: cs.DC Possible cross-list: cs.PF
Static-graph LLM decoders provide predictable launches, fixed tensor shapes, and low submission overhead, but online decoding exposes highly irregular KV-cache behavior: request lengths differ, EOS events arrive asynchronously, and logical histories fragment over time. Dynamic runtimes recover flexibility through paged KV management and step-level scheduling, while static-graph executors often over-reserve memory and suffer burst-time latency outliers. This paper studies whether much of this variability can be absorbed below a fixed decode interface. We present KV-RM, a runtime design that regularizes KV-cache movement beneath a static-graph LLM decoder. KV-RM decouples logical KV histories from physical storage, tracks active KV state through a block pager, and materializes each decode step through a single committed descriptor. A merge-staged transport path coalesces non-contiguous KV mappings into a small number of large transfer groups before a fixed-shape attention kernel consumes them. Optional bounded far-history summaries can be enabled under the same interface, but the core design does not depend on them. On a 2-GPU NVIDIA A100 node, KV-RM improves mixed-length decoding throughput and tail latency relative to a static-graph baseline, reduces reserved KV memory across workload families, and removes severe burst-time latency spikes under production-trace replay. These results suggest that KV-cache movement, rather than kernel shape, can be an effective boundary for recovering runtime flexibility in static-graph LLM serving.
title KV-RM: Regularizing KV-Cache Movement for Static-Graph LLM Serving
topic Hardware Architecture
Artificial Intelligence
Distributed, Parallel, and Cluster Computing
Operating Systems
Primary category: cs.DC Possible cross-list: cs.PF
url https://arxiv.org/abs/2605.09735