CodeGEMM: A Codebook-Centric Approach to Efficient GEMM in Quantized LLMs

Fuente: arXiv
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Main Authors: Park, Gunho, Bae, Jeongin, Kim, Byeongwook, park, Baeseong, Ryu, Jiwon, Kim, Hoseung, Kwon, Se Jung, Lee, Dongsoo
Format: Preprint
Published: 2025
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author Park, Gunho
Bae, Jeongin
Kim, Byeongwook
park, Baeseong
Ryu, Jiwon
Kim, Hoseung
Kwon, Se Jung
Lee, Dongsoo
author_facet Park, Gunho
Bae, Jeongin
Kim, Byeongwook
park, Baeseong
Ryu, Jiwon
Kim, Hoseung
Kwon, Se Jung
Lee, Dongsoo
contents Weight-only quantization is widely used to mitigate the memory-bound nature of LLM inference. Codebook-based methods extend this trend by achieving strong accuracy in the extremely low-bit regime (e.g., 2-bit). However, current kernels rely on dequantization, which repeatedly fetches centroids and reconstructs weights, incurring substantial latency and cache pressure. We present CodeGEMM, a codebook-centric GEMM kernel that replaces dequantization with precomputed inner products between centroids and activations stored in a lightweight Psumbook. At inference, code indices directly gather these partial sums, eliminating per-element lookups and reducing the on-chip footprint. The kernel supports the systematic exploration of latency-memory-accuracy trade-offs under a unified implementation. On Llama-3 models, CodeGEMM delivers 1.83x (8B) and 8.93x (70B) speedups in the 2-bit configuration compared to state-of-the-art codebook-based quantization at comparable accuracy and further improves computing efficiency and memory subsystem utilization.
format Preprint
id arxiv_https___arxiv_org_abs_2512_17970
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle CodeGEMM: A Codebook-Centric Approach to Efficient GEMM in Quantized LLMs
Park, Gunho
Bae, Jeongin
Kim, Byeongwook
park, Baeseong
Ryu, Jiwon
Kim, Hoseung
Kwon, Se Jung
Lee, Dongsoo
Machine Learning
Artificial Intelligence
Weight-only quantization is widely used to mitigate the memory-bound nature of LLM inference. Codebook-based methods extend this trend by achieving strong accuracy in the extremely low-bit regime (e.g., 2-bit). However, current kernels rely on dequantization, which repeatedly fetches centroids and reconstructs weights, incurring substantial latency and cache pressure. We present CodeGEMM, a codebook-centric GEMM kernel that replaces dequantization with precomputed inner products between centroids and activations stored in a lightweight Psumbook. At inference, code indices directly gather these partial sums, eliminating per-element lookups and reducing the on-chip footprint. The kernel supports the systematic exploration of latency-memory-accuracy trade-offs under a unified implementation. On Llama-3 models, CodeGEMM delivers 1.83x (8B) and 8.93x (70B) speedups in the 2-bit configuration compared to state-of-the-art codebook-based quantization at comparable accuracy and further improves computing efficiency and memory subsystem utilization.
title CodeGEMM: A Codebook-Centric Approach to Efficient GEMM in Quantized LLMs
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2512.17970