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Main Authors: Liu, Songtao, Peng, Hongwu, Zhang, Zhiwei, Chen, Zhengyu, Guo, Yue
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2603.02188
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author Liu, Songtao
Peng, Hongwu
Zhang, Zhiwei
Chen, Zhengyu
Guo, Yue
author_facet Liu, Songtao
Peng, Hongwu
Zhang, Zhiwei
Chen, Zhengyu
Guo, Yue
contents Long-context inference in large language models is bottlenecked by Key--Value (KV) cache loading during the decoding stage, where the sequential nature of generation requires repeatedly transferring the KV cache from off-chip High-Bandwidth Memory (HBM) to on-chip Static Random-Access Memory (SRAM) at each step. While Multi-Head Latent Attention (MLA) significantly reduces the total KV cache size, it suffers from a sharding bottleneck during distributed decoding via Tensor Parallelism (TP). Since its single latent head cannot be partitioned, each device is forced to redundantly load the complete KV cache for every token, consuming excessive memory traffic and diminishing TP benefits like weight sharding. In this work, we propose Multi-Head Low-Rank Attention (MLRA), which enables partitionable latent states for efficient 4-way TP decoding. Extensive experiments show that MLRA achieves state-of-the-art perplexity and downstream task performance, while also delivering a 2.8$\times$ decoding speedup over MLA. Code is available at https://github.com/SongtaoLiu0823/MLRA. Pretrained weights, along with the training and evaluation data, are available at https://huggingface.co/Soughing/MLRA.
format Preprint
id arxiv_https___arxiv_org_abs_2603_02188
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Multi-Head Low-Rank Attention
Liu, Songtao
Peng, Hongwu
Zhang, Zhiwei
Chen, Zhengyu
Guo, Yue
Machine Learning
Long-context inference in large language models is bottlenecked by Key--Value (KV) cache loading during the decoding stage, where the sequential nature of generation requires repeatedly transferring the KV cache from off-chip High-Bandwidth Memory (HBM) to on-chip Static Random-Access Memory (SRAM) at each step. While Multi-Head Latent Attention (MLA) significantly reduces the total KV cache size, it suffers from a sharding bottleneck during distributed decoding via Tensor Parallelism (TP). Since its single latent head cannot be partitioned, each device is forced to redundantly load the complete KV cache for every token, consuming excessive memory traffic and diminishing TP benefits like weight sharding. In this work, we propose Multi-Head Low-Rank Attention (MLRA), which enables partitionable latent states for efficient 4-way TP decoding. Extensive experiments show that MLRA achieves state-of-the-art perplexity and downstream task performance, while also delivering a 2.8$\times$ decoding speedup over MLA. Code is available at https://github.com/SongtaoLiu0823/MLRA. Pretrained weights, along with the training and evaluation data, are available at https://huggingface.co/Soughing/MLRA.
title Multi-Head Low-Rank Attention
topic Machine Learning
url https://arxiv.org/abs/2603.02188