Taming Sensitive Weights : Noise Perturbation Fine-tuning for Robust LLM Quantization

Fuente: arXiv
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Main Authors: Wang, Dongwei, Yang, Huanrui
Format: Preprint
Published: 2024
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author Wang, Dongwei
Yang, Huanrui
author_facet Wang, Dongwei
Yang, Huanrui
contents Quantization is a critical step to enable efficient LLM serving under limited resource. However, previous research observes that certain weights in the LLM, known as outliers, are significantly sensitive to quantization noises. Existing quantization methods leave these outliers as floating points or higher precisions to retain performance, posting challenges on the efficient hardware deployment of the mixed-precision model. This work investigates an alternative way to tame the sensitive weights' impact on the quantization error, by reducing the loss Hessian trace with respect to outliers through an efficient fine-tuning process. We propose Noise Perturbation Fine-tuning (NPFT), which identifies outlier weights and add random weight perturbations on the outliers as the model going through a PEFT optimization. NPFT tames the sensitivity of outlier weights so that the quantized model performance can be improved without special treatment to the outliers. When applied to OPT and LLaMA models, our NPFT method achieves stable performance improvements for both uniform and non-uniform quantizers, while also offering better inference efficiency. Notably, the simplest RTN can achieve performance on par with GPTQ using our NPFT on LLaMA2-7B-4bits benchmark.
format Preprint
id arxiv_https___arxiv_org_abs_2412_06858
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Taming Sensitive Weights : Noise Perturbation Fine-tuning for Robust LLM Quantization
Wang, Dongwei
Yang, Huanrui
Machine Learning
Artificial Intelligence
Computation and Language
Quantization is a critical step to enable efficient LLM serving under limited resource. However, previous research observes that certain weights in the LLM, known as outliers, are significantly sensitive to quantization noises. Existing quantization methods leave these outliers as floating points or higher precisions to retain performance, posting challenges on the efficient hardware deployment of the mixed-precision model. This work investigates an alternative way to tame the sensitive weights' impact on the quantization error, by reducing the loss Hessian trace with respect to outliers through an efficient fine-tuning process. We propose Noise Perturbation Fine-tuning (NPFT), which identifies outlier weights and add random weight perturbations on the outliers as the model going through a PEFT optimization. NPFT tames the sensitivity of outlier weights so that the quantized model performance can be improved without special treatment to the outliers. When applied to OPT and LLaMA models, our NPFT method achieves stable performance improvements for both uniform and non-uniform quantizers, while also offering better inference efficiency. Notably, the simplest RTN can achieve performance on par with GPTQ using our NPFT on LLaMA2-7B-4bits benchmark.
title Taming Sensitive Weights : Noise Perturbation Fine-tuning for Robust LLM Quantization
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2412.06858