Pangu Light: Weight Re-Initialization for Pruning and Accelerating LLMs

Fuente: arXiv
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Main Authors: Chen, Hanting, Qin, Jiarui, Guo, Jialong, Yuan, Tao, Yin, Yichun, Zhen, Huiling, Wang, Yasheng, Li, Jinpeng, Meng, Xiaojun, Zhang, Meng, Ruan, Rongju, Bai, Zheyuan, Tang, Yehui, Chen, Can, Chen, Xinghao, Yu, Fisher, Tang, Ruiming, Wang, Yunhe
Format: Preprint
Published: 2025
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author Chen, Hanting
Qin, Jiarui
Guo, Jialong
Yuan, Tao
Yin, Yichun
Zhen, Huiling
Wang, Yasheng
Li, Jinpeng
Meng, Xiaojun
Zhang, Meng
Ruan, Rongju
Bai, Zheyuan
Tang, Yehui
Chen, Can
Chen, Xinghao
Yu, Fisher
Tang, Ruiming
Wang, Yunhe
author_facet Chen, Hanting
Qin, Jiarui
Guo, Jialong
Yuan, Tao
Yin, Yichun
Zhen, Huiling
Wang, Yasheng
Li, Jinpeng
Meng, Xiaojun
Zhang, Meng
Ruan, Rongju
Bai, Zheyuan
Tang, Yehui
Chen, Can
Chen, Xinghao
Yu, Fisher
Tang, Ruiming
Wang, Yunhe
contents Large Language Models (LLMs) deliver state-of-the-art capabilities across numerous tasks, but their immense size and inference costs pose significant computational challenges for practical deployment. While structured pruning offers a promising avenue for model compression, existing methods often struggle with the detrimental effects of aggressive, simultaneous width and depth reductions, leading to substantial performance degradation. This paper argues that a critical, often overlooked, aspect in making such aggressive joint pruning viable is the strategic re-initialization and adjustment of remaining weights to improve the model post-pruning training accuracies. We introduce Pangu Light, a framework for LLM acceleration centered around structured pruning coupled with novel weight re-initialization techniques designed to address this ``missing piece''. Our framework systematically targets multiple axes, including model width, depth, attention heads, and RMSNorm, with its effectiveness rooted in novel re-initialization methods like Cross-Layer Attention Pruning (CLAP) and Stabilized LayerNorm Pruning (SLNP) that mitigate performance drops by providing the network a better training starting point. Further enhancing efficiency, Pangu Light incorporates specialized optimizations such as absorbing Post-RMSNorm computations and tailors its strategies to Ascend NPU characteristics. The Pangu Light models consistently exhibit a superior accuracy-efficiency trade-off, outperforming prominent baseline pruning methods like Nemotron and established LLMs like Qwen3 series. For instance, on Ascend NPUs, Pangu Light-32B's 81.6 average score and 2585 tokens/s throughput exceed Qwen3-32B's 80.9 average score and 2225 tokens/s.
format Preprint
id arxiv_https___arxiv_org_abs_2505_20155
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Pangu Light: Weight Re-Initialization for Pruning and Accelerating LLMs
Chen, Hanting
Qin, Jiarui
Guo, Jialong
Yuan, Tao
Yin, Yichun
Zhen, Huiling
Wang, Yasheng
Li, Jinpeng
Meng, Xiaojun
Zhang, Meng
Ruan, Rongju
Bai, Zheyuan
Tang, Yehui
Chen, Can
Chen, Xinghao
Yu, Fisher
Tang, Ruiming
Wang, Yunhe
Computation and Language
Large Language Models (LLMs) deliver state-of-the-art capabilities across numerous tasks, but their immense size and inference costs pose significant computational challenges for practical deployment. While structured pruning offers a promising avenue for model compression, existing methods often struggle with the detrimental effects of aggressive, simultaneous width and depth reductions, leading to substantial performance degradation. This paper argues that a critical, often overlooked, aspect in making such aggressive joint pruning viable is the strategic re-initialization and adjustment of remaining weights to improve the model post-pruning training accuracies. We introduce Pangu Light, a framework for LLM acceleration centered around structured pruning coupled with novel weight re-initialization techniques designed to address this ``missing piece''. Our framework systematically targets multiple axes, including model width, depth, attention heads, and RMSNorm, with its effectiveness rooted in novel re-initialization methods like Cross-Layer Attention Pruning (CLAP) and Stabilized LayerNorm Pruning (SLNP) that mitigate performance drops by providing the network a better training starting point. Further enhancing efficiency, Pangu Light incorporates specialized optimizations such as absorbing Post-RMSNorm computations and tailors its strategies to Ascend NPU characteristics. The Pangu Light models consistently exhibit a superior accuracy-efficiency trade-off, outperforming prominent baseline pruning methods like Nemotron and established LLMs like Qwen3 series. For instance, on Ascend NPUs, Pangu Light-32B's 81.6 average score and 2585 tokens/s throughput exceed Qwen3-32B's 80.9 average score and 2225 tokens/s.
title Pangu Light: Weight Re-Initialization for Pruning and Accelerating LLMs
topic Computation and Language
url https://arxiv.org/abs/2505.20155