ParoQuant: Pairwise Rotation Quantization for Efficient Reasoning LLM Inference

Fuente: arXiv
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Main Authors: Liang, Yesheng, Chen, Haisheng, Zhang, Zihan, Han, Song, Liu, Zhijian
Format: Preprint
Published: 2025
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author Liang, Yesheng
Chen, Haisheng
Zhang, Zihan
Han, Song
Liu, Zhijian
author_facet Liang, Yesheng
Chen, Haisheng
Zhang, Zihan
Han, Song
Liu, Zhijian
contents Post-training quantization (PTQ) compresses the weights and activations of large language models (LLMs) into low-precision representations to reduce memory footprint and accelerate inference. However, the presence of outliers in weights and activations often leads to large quantization errors and severe accuracy degradation, especially in recent reasoning LLMs where errors accumulate across long chains of thought. Existing PTQ methods either fail to sufficiently suppress outliers or introduce significant overhead during inference. In this paper, we propose Pairwise Rotation Quantization (ParoQuant), a PTQ method that combines hardware-efficient and optimizable independent Givens rotations with channel-wise scaling to even out the magnitudes across channels and narrow the dynamic range within each quantization group, effectively addressing the outlier issue. We further co-design the inference kernel to fully exploit GPU parallelism and keep the rotations and scaling lightweight at runtime. Under weight-only quantization, ParoQuant achieves an average 2.4% accuracy improvement over AWQ on reasoning tasks, with less than 10% overhead. ParoQuant also matches the accuracy of state-of-the-art weight-activation quantization methods. This paves the way for more efficient and accurate deployment of reasoning LLMs.
format Preprint
id arxiv_https___arxiv_org_abs_2511_10645
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle ParoQuant: Pairwise Rotation Quantization for Efficient Reasoning LLM Inference
Liang, Yesheng
Chen, Haisheng
Zhang, Zihan
Han, Song
Liu, Zhijian
Computation and Language
Post-training quantization (PTQ) compresses the weights and activations of large language models (LLMs) into low-precision representations to reduce memory footprint and accelerate inference. However, the presence of outliers in weights and activations often leads to large quantization errors and severe accuracy degradation, especially in recent reasoning LLMs where errors accumulate across long chains of thought. Existing PTQ methods either fail to sufficiently suppress outliers or introduce significant overhead during inference. In this paper, we propose Pairwise Rotation Quantization (ParoQuant), a PTQ method that combines hardware-efficient and optimizable independent Givens rotations with channel-wise scaling to even out the magnitudes across channels and narrow the dynamic range within each quantization group, effectively addressing the outlier issue. We further co-design the inference kernel to fully exploit GPU parallelism and keep the rotations and scaling lightweight at runtime. Under weight-only quantization, ParoQuant achieves an average 2.4% accuracy improvement over AWQ on reasoning tasks, with less than 10% overhead. ParoQuant also matches the accuracy of state-of-the-art weight-activation quantization methods. This paves the way for more efficient and accurate deployment of reasoning LLMs.
title ParoQuant: Pairwise Rotation Quantization for Efficient Reasoning LLM Inference
topic Computation and Language
url https://arxiv.org/abs/2511.10645