Rethinking LLM Inference Bottlenecks: Insights from Latent Attention and Mixture-of-Experts

Fuente: arXiv
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Autori principali: Yun, Sungmin, Park, Seonyong, Nam, Hwayong, Lee, Younjoo, Lee, Gunjun, Kyung, Kwanhee, Kim, Sangpyo, Kim, Nam Sung, Kim, Jongmin, Kim, Hyungyo, Cho, Juhwan, Baek, Seungmin, Ahn, Jung Ho
Natura: Preprint
Pubblicazione: 2025
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author Yun, Sungmin
Park, Seonyong
Nam, Hwayong
Lee, Younjoo
Lee, Gunjun
Kyung, Kwanhee
Kim, Sangpyo
Kim, Nam Sung
Kim, Jongmin
Kim, Hyungyo
Cho, Juhwan
Baek, Seungmin
Ahn, Jung Ho
author_facet Yun, Sungmin
Park, Seonyong
Nam, Hwayong
Lee, Younjoo
Lee, Gunjun
Kyung, Kwanhee
Kim, Sangpyo
Kim, Nam Sung
Kim, Jongmin
Kim, Hyungyo
Cho, Juhwan
Baek, Seungmin
Ahn, Jung Ho
contents Computational workloads composing traditional transformer models are starkly bifurcated. Multi-Head Attention (MHA) and Grouped-Query Attention are memory-bound due to low arithmetic intensity, while FeedForward Networks are compute-bound. This dichotomy has long motivated research into specialized hardware to mitigate the attention bottleneck. This paper argues that recent architectural advances in transformer models -- Multi-head Latent Attention (MLA) and Mixture of Experts (MoE) -- introduce new dominant bottlenecks, shifting the challenge away from memory-intensive attention. We make two key observations. First, the arithmetic intensity of MLA is over two orders of magnitude higher than that of MHA, moving it toward a compute-bound regime well-matched to modern accelerators such as GPUs. Second, distributing MoE experts across a pool of accelerators allows batching to tune their arithmetic intensity to that of dense layers, producing a more balanced computational profile. Consequently, the focus of hardware and system optimization should shift from attention acceleration to high-bandwidth interconnects and balancing expert workloads across accelerators.
format Preprint
id arxiv_https___arxiv_org_abs_2507_15465
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Rethinking LLM Inference Bottlenecks: Insights from Latent Attention and Mixture-of-Experts
Yun, Sungmin
Park, Seonyong
Nam, Hwayong
Lee, Younjoo
Lee, Gunjun
Kyung, Kwanhee
Kim, Sangpyo
Kim, Nam Sung
Kim, Jongmin
Kim, Hyungyo
Cho, Juhwan
Baek, Seungmin
Ahn, Jung Ho
Hardware Architecture
Artificial Intelligence
Computational workloads composing traditional transformer models are starkly bifurcated. Multi-Head Attention (MHA) and Grouped-Query Attention are memory-bound due to low arithmetic intensity, while FeedForward Networks are compute-bound. This dichotomy has long motivated research into specialized hardware to mitigate the attention bottleneck. This paper argues that recent architectural advances in transformer models -- Multi-head Latent Attention (MLA) and Mixture of Experts (MoE) -- introduce new dominant bottlenecks, shifting the challenge away from memory-intensive attention. We make two key observations. First, the arithmetic intensity of MLA is over two orders of magnitude higher than that of MHA, moving it toward a compute-bound regime well-matched to modern accelerators such as GPUs. Second, distributing MoE experts across a pool of accelerators allows batching to tune their arithmetic intensity to that of dense layers, producing a more balanced computational profile. Consequently, the focus of hardware and system optimization should shift from attention acceleration to high-bandwidth interconnects and balancing expert workloads across accelerators.
title Rethinking LLM Inference Bottlenecks: Insights from Latent Attention and Mixture-of-Experts
topic Hardware Architecture
Artificial Intelligence
url https://arxiv.org/abs/2507.15465