KVDirect: Distributed Disaggregated LLM Inference

Fuente: arXiv
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Hauptverfasser: Chen, Shiyang, Jiang, Rain, Yu, Dezhi, Xu, Jinlai, Chao, Mengyuan, Meng, Fanlong, Jiang, Chenyu, Xu, Wei, Liu, Hang
Format: Preprint
Veröffentlicht: 2024
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author Chen, Shiyang
Jiang, Rain
Yu, Dezhi
Xu, Jinlai
Chao, Mengyuan
Meng, Fanlong
Jiang, Chenyu
Xu, Wei
Liu, Hang
author_facet Chen, Shiyang
Jiang, Rain
Yu, Dezhi
Xu, Jinlai
Chao, Mengyuan
Meng, Fanlong
Jiang, Chenyu
Xu, Wei
Liu, Hang
contents Large Language Models (LLMs) have become the new foundation for many applications, reshaping human society like a storm. Disaggregated inference, which separates prefill and decode stages, is a promising approach to improving hardware utilization and service quality. However, due to inefficient inter-node communication, existing systems restrict disaggregated inference to a single node, limiting resource allocation flexibility and reducing service capacity. This paper introduces KVDirect, which optimizes KV cache transfer to enable a distributed disaggregated LLM inference. KVDirect achieves this through the following contributions. First, we propose a novel tensor-centric communication mechanism that reduces the synchronization overhead in traditional distributed GPU systems. Second, we design a custom communication library to support dynamic GPU resource scheduling and efficient KV cache transfer. Third, we introduce a pull-based KV cache transfer strategy that reduces GPU resource idling and improves latency. Finally, we implement KVDirect as an open-source LLM inference framework. Our evaluation demonstrates that KVDirect reduces per-request latency by 55% compared to the baseline across diverse workloads under the same resource constraints.
format Preprint
id arxiv_https___arxiv_org_abs_2501_14743
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle KVDirect: Distributed Disaggregated LLM Inference
Chen, Shiyang
Jiang, Rain
Yu, Dezhi
Xu, Jinlai
Chao, Mengyuan
Meng, Fanlong
Jiang, Chenyu
Xu, Wei
Liu, Hang
Distributed, Parallel, and Cluster Computing
Machine Learning
Performance
Large Language Models (LLMs) have become the new foundation for many applications, reshaping human society like a storm. Disaggregated inference, which separates prefill and decode stages, is a promising approach to improving hardware utilization and service quality. However, due to inefficient inter-node communication, existing systems restrict disaggregated inference to a single node, limiting resource allocation flexibility and reducing service capacity. This paper introduces KVDirect, which optimizes KV cache transfer to enable a distributed disaggregated LLM inference. KVDirect achieves this through the following contributions. First, we propose a novel tensor-centric communication mechanism that reduces the synchronization overhead in traditional distributed GPU systems. Second, we design a custom communication library to support dynamic GPU resource scheduling and efficient KV cache transfer. Third, we introduce a pull-based KV cache transfer strategy that reduces GPU resource idling and improves latency. Finally, we implement KVDirect as an open-source LLM inference framework. Our evaluation demonstrates that KVDirect reduces per-request latency by 55% compared to the baseline across diverse workloads under the same resource constraints.
title KVDirect: Distributed Disaggregated LLM Inference
topic Distributed, Parallel, and Cluster Computing
Machine Learning
Performance
url https://arxiv.org/abs/2501.14743