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Bibliographic Details
Main Authors: Liu, Yang, Chen, Yi, Zhao, Yongwei, Hao, Yifan, Zheng, Zifu, Kong, Weihao, Li, Zhangmai, Jiang, Dongchen, Xia, Ruiyang, Ma, Zhihong, Liu, Zisheng, Wan, Zhaoyong, Lu, Yunqi, Liu, Ximing, Guo, Hongrui, Yang, Zhihao, Wang, Zhe, Ma, Tianrui, Zou, Mo, Zhang, Rui, Li, Ling, Hu, Xing, Du, Zidong, Xu, Zhiwei, Guo, Qi, Chen, Tianshi, Chen, Yunji
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2508.16151
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Table of Contents:
  • The rapid advancement of Large Language Models (LLMs) has established language as a core general-purpose cognitive substrate, driving the demand for specialized Language Processing Units (LPUs) tailored for LLM inference. To overcome the growing energy consumption of LLM inference systems, this paper proposes a Hardwired-Neurons Language Processing Unit (HNLPU), which physically hardwires LLM weight parameters into the computational fabric, achieving several orders of magnitude computational efficiency improvement by extreme specialization. However, a significant challenge still lies in the scale of modern LLMs. A straightforward hardwiring of gpt-oss 120 B would require fabricating photomask sets valued at over 6 billion dollars, rendering this straightforward solution economically impractical. Addressing this challenge, we propose the novel Metal-Embedding methodology. Instead of embedding weights in a 2D grid of silicon device cells, Metal-Embedding embeds weight parameters into the 3D topology of metal wires. This brings two benefits: (1) a 15x increase in density, and (2) 60 out of 70 photomask layers are homogeneous across chips, including all EUV photomasks. In total, Metal-Embedding reduced the photomask cost by 112x, bringing the Non-Recurring Engineering (NRE) cost of HNLPU into an economically viable range. Experimental results show that HNLPU achieved 249,960 tokens/s (5,555x/85x that of GPU/WSE), 36 tokens/J (1,047x/283x that of GPU/WSE), 13,232 mm2 total die area, $59.46 M-123.5 M estimated NRE at 5 nm technology. Analysis shows that HNLPU achieved 41.7-80.4x improvement in cost-effectiveness and 357x reduction in carbon footprint compared to OpenAI-scale H100 clusters, under an annual weight updating assumption.