Oneiros: KV Cache Optimization through Parameter Remapping for Multi-tenant LLM Serving

Fuente: arXiv
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Main Authors: Li, Ruihao, Pal, Shagnik, Pullu, Vineeth Narayan, Sinha, Prasoon, Ryoo, Jeeho, John, Lizy K., Yadwadkar, Neeraja J.
Format: Preprint
Published: 2025
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author Li, Ruihao
Pal, Shagnik
Pullu, Vineeth Narayan
Sinha, Prasoon
Ryoo, Jeeho
John, Lizy K.
Yadwadkar, Neeraja J.
author_facet Li, Ruihao
Pal, Shagnik
Pullu, Vineeth Narayan
Sinha, Prasoon
Ryoo, Jeeho
John, Lizy K.
Yadwadkar, Neeraja J.
contents KV cache accelerates LLM inference by avoiding redundant computation, at the expense of memory. To support larger KV caches, prior work extends GPU memory with CPU memory via CPU-offloading. This involves swapping KV cache between GPU and CPU memory. However, because the cache updates dynamically, such swapping incurs high CPU memory traffic. We make a key observation that model parameters remain constant during runtime, unlike the dynamically updated KV cache. Building on this, we introduce Oneiros, which avoids KV cache swapping by remapping, and thereby repurposing, the memory allocated to model parameters for KV cache. This parameter remapping is especially beneficial in multi-tenant environments, where the memory used for the parameters of the inactive models can be more aggressively reclaimed. Exploiting the high CPU-GPU bandwidth offered by the modern hardware, such as the NVIDIA Grace Hopper Superchip, we show that Oneiros significantly outperforms state-of-the-art solutions, achieving a reduction of 44.8%-82.5% in tail time-between-token latency, 20.7%-99.3% in tail time-to-first-token latency, and 6.6%-86.7% higher throughput compared to vLLM. Source code of Oneiros is available at https://github.com/UT-SysML/Oneiros/.
format Preprint
id arxiv_https___arxiv_org_abs_2507_11507
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Oneiros: KV Cache Optimization through Parameter Remapping for Multi-tenant LLM Serving
Li, Ruihao
Pal, Shagnik
Pullu, Vineeth Narayan
Sinha, Prasoon
Ryoo, Jeeho
John, Lizy K.
Yadwadkar, Neeraja J.
Operating Systems
KV cache accelerates LLM inference by avoiding redundant computation, at the expense of memory. To support larger KV caches, prior work extends GPU memory with CPU memory via CPU-offloading. This involves swapping KV cache between GPU and CPU memory. However, because the cache updates dynamically, such swapping incurs high CPU memory traffic. We make a key observation that model parameters remain constant during runtime, unlike the dynamically updated KV cache. Building on this, we introduce Oneiros, which avoids KV cache swapping by remapping, and thereby repurposing, the memory allocated to model parameters for KV cache. This parameter remapping is especially beneficial in multi-tenant environments, where the memory used for the parameters of the inactive models can be more aggressively reclaimed. Exploiting the high CPU-GPU bandwidth offered by the modern hardware, such as the NVIDIA Grace Hopper Superchip, we show that Oneiros significantly outperforms state-of-the-art solutions, achieving a reduction of 44.8%-82.5% in tail time-between-token latency, 20.7%-99.3% in tail time-to-first-token latency, and 6.6%-86.7% higher throughput compared to vLLM. Source code of Oneiros is available at https://github.com/UT-SysML/Oneiros/.
title Oneiros: KV Cache Optimization through Parameter Remapping for Multi-tenant LLM Serving
topic Operating Systems
url https://arxiv.org/abs/2507.11507