Towards Compute-Aware In-Switch Computing for LLMs Tensor-Parallelism on Multi-GPU Systems

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Hauptverfasser: Zhang, Chen, Zhang, Qijun, Zhou, Zhuoshan, Diao, Yijia, Wang, Haibo, Zhou, Zhe, Tu, Zhipeng, Li, Zhiyao, Sun, Guangyu, Song, Zhuoran, Ji, Zhigang, Leng, Jingwen, Guo, Minyi
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Veröffentlicht: 2026
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author Zhang, Chen
Zhang, Qijun
Zhou, Zhuoshan
Diao, Yijia
Wang, Haibo
Zhou, Zhe
Tu, Zhipeng
Li, Zhiyao
Sun, Guangyu
Song, Zhuoran
Ji, Zhigang
Leng, Jingwen
Guo, Minyi
author_facet Zhang, Chen
Zhang, Qijun
Zhou, Zhuoshan
Diao, Yijia
Wang, Haibo
Zhou, Zhe
Tu, Zhipeng
Li, Zhiyao
Sun, Guangyu
Song, Zhuoran
Ji, Zhigang
Leng, Jingwen
Guo, Minyi
contents Tensor parallelism (TP) in large-scale LLM inference and training introduces frequent collective operations that dominate inter-GPU communication. While in-switch computing, exemplified by NVLink SHARP (NVLS), accelerates collective operations by reducing redundant data transfer, its communication-centric design philosophy introduces the mismatch between its communication mode and the memory semantic requirement of LLM's computation kernel. Such a mismatch isolates the compute and communication phases, resulting in underutilized resources and limited overlap in multi-GPU systems. To address the limitation, we propose CAIS, the first Compute-Aware In-Switch computing framework that aligns communication modes with computation's memory semantics requirement. CAIS consists of three integral techniques: (1) compute-aware ISA and microarchitecture extension to enable compute-aware in-switch computing. (2) merging-aware TB (Thread Block) coordination to improve the temporal alignment for efficient request merging. (3) graph-level dataflow optimizer to achieve a tight cross-kernel overlap. Evaluations on LLM workloads show that CAIS achieves 1.38$\times$ average end-to-end training speedup over the SOTA NVLS-enabled solution, and 1.61$\times$ over T3, the SOTA compute-communicate overlap solutions but do not leverage NVLS, demonstrating its effectiveness in accelerating TP on multi-GPU systems.
format Preprint
id arxiv_https___arxiv_org_abs_2605_05628
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Towards Compute-Aware In-Switch Computing for LLMs Tensor-Parallelism on Multi-GPU Systems
Zhang, Chen
Zhang, Qijun
Zhou, Zhuoshan
Diao, Yijia
Wang, Haibo
Zhou, Zhe
Tu, Zhipeng
Li, Zhiyao
Sun, Guangyu
Song, Zhuoran
Ji, Zhigang
Leng, Jingwen
Guo, Minyi
Hardware Architecture
Distributed, Parallel, and Cluster Computing
Tensor parallelism (TP) in large-scale LLM inference and training introduces frequent collective operations that dominate inter-GPU communication. While in-switch computing, exemplified by NVLink SHARP (NVLS), accelerates collective operations by reducing redundant data transfer, its communication-centric design philosophy introduces the mismatch between its communication mode and the memory semantic requirement of LLM's computation kernel. Such a mismatch isolates the compute and communication phases, resulting in underutilized resources and limited overlap in multi-GPU systems. To address the limitation, we propose CAIS, the first Compute-Aware In-Switch computing framework that aligns communication modes with computation's memory semantics requirement. CAIS consists of three integral techniques: (1) compute-aware ISA and microarchitecture extension to enable compute-aware in-switch computing. (2) merging-aware TB (Thread Block) coordination to improve the temporal alignment for efficient request merging. (3) graph-level dataflow optimizer to achieve a tight cross-kernel overlap. Evaluations on LLM workloads show that CAIS achieves 1.38$\times$ average end-to-end training speedup over the SOTA NVLS-enabled solution, and 1.61$\times$ over T3, the SOTA compute-communicate overlap solutions but do not leverage NVLS, demonstrating its effectiveness in accelerating TP on multi-GPU systems.
title Towards Compute-Aware In-Switch Computing for LLMs Tensor-Parallelism on Multi-GPU Systems
topic Hardware Architecture
Distributed, Parallel, and Cluster Computing
url https://arxiv.org/abs/2605.05628