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Main Authors: Zhao, Junchen, Derakhshan, Ali, Hyman, Jayden Kana, Dong, Junhao, Jyothi, Sangeetha Abdu, Harris, Ian
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2509.15455
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author Zhao, Junchen
Derakhshan, Ali
Hyman, Jayden Kana
Dong, Junhao
Jyothi, Sangeetha Abdu
Harris, Ian
author_facet Zhao, Junchen
Derakhshan, Ali
Hyman, Jayden Kana
Dong, Junhao
Jyothi, Sangeetha Abdu
Harris, Ian
contents Large Language Models (LLMs) promise impressive capabilities, yet their multi-billion-parameter scale makes on-device or low-resource deployment prohibitive. Mixed-precision quantization offers a compelling solution, but existing methods struggle when the average precision drops below four bits, as they rely on isolated, layer-specific metrics that overlook critical inter-layer interactions affecting overall performance. To address these limitations, we first frame the mixed-precision quantization problem as a cooperative game among layers and introduce Shapley-based Progressive Quantization Estimation (SPQE) to efficiently obtain accurate Shapley estimates of layer sensitivities and inter-layer interactions. Leveraging the SPQE estimates, we propose Cooperative Game Inspired Mixed-Precision Quantization (CoopQ) which translates these Shapley estimates into a binary quadratic optimization formulation, assigning either 2 or 4-bit precision to layers under strict memory constraints. Comprehensive experiments conducted on Llama-3, Gemma-2, and Qwen-3 models across three independent PTQ backends (Quanto, HQQ, GPTQ) demonstrate CoopQ's scalability and consistently superior performance compared to methods relying solely on isolated metrics. Across average precisions spanning 4 bit down to 2 bit, CoopQ cuts Perplexity by 20 - 80 % relative to the best baseline, with the margin growing as the bit-width tightens.
format Preprint
id arxiv_https___arxiv_org_abs_2509_15455
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle CoopQ: Cooperative Game Inspired Layerwise Mixed Precision Quantization for LLMs
Zhao, Junchen
Derakhshan, Ali
Hyman, Jayden Kana
Dong, Junhao
Jyothi, Sangeetha Abdu
Harris, Ian
Machine Learning
Large Language Models (LLMs) promise impressive capabilities, yet their multi-billion-parameter scale makes on-device or low-resource deployment prohibitive. Mixed-precision quantization offers a compelling solution, but existing methods struggle when the average precision drops below four bits, as they rely on isolated, layer-specific metrics that overlook critical inter-layer interactions affecting overall performance. To address these limitations, we first frame the mixed-precision quantization problem as a cooperative game among layers and introduce Shapley-based Progressive Quantization Estimation (SPQE) to efficiently obtain accurate Shapley estimates of layer sensitivities and inter-layer interactions. Leveraging the SPQE estimates, we propose Cooperative Game Inspired Mixed-Precision Quantization (CoopQ) which translates these Shapley estimates into a binary quadratic optimization formulation, assigning either 2 or 4-bit precision to layers under strict memory constraints. Comprehensive experiments conducted on Llama-3, Gemma-2, and Qwen-3 models across three independent PTQ backends (Quanto, HQQ, GPTQ) demonstrate CoopQ's scalability and consistently superior performance compared to methods relying solely on isolated metrics. Across average precisions spanning 4 bit down to 2 bit, CoopQ cuts Perplexity by 20 - 80 % relative to the best baseline, with the margin growing as the bit-width tightens.
title CoopQ: Cooperative Game Inspired Layerwise Mixed Precision Quantization for LLMs
topic Machine Learning
url https://arxiv.org/abs/2509.15455