TaQ-DiT: Time-aware Quantization for Diffusion Transformers

Fuente: arXiv
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Main Authors: Liu, Xinyan, Shi, Huihong, Xu, Yang, Wang, Zhongfeng
Format: Preprint
Published: 2024
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author Liu, Xinyan
Shi, Huihong
Xu, Yang
Wang, Zhongfeng
author_facet Liu, Xinyan
Shi, Huihong
Xu, Yang
Wang, Zhongfeng
contents Transformer-based diffusion models, dubbed Diffusion Transformers (DiTs), have achieved state-of-the-art performance in image and video generation tasks. However, their large model size and slow inference speed limit their practical applications, calling for model compression methods such as quantization. Unfortunately, existing DiT quantization methods overlook (1) the impact of reconstruction and (2) the varying quantization sensitivities across different layers, which hinder their achievable performance. To tackle these issues, we propose innovative time-aware quantization for DiTs (TaQ-DiT). Specifically, (1) we observe a non-convergence issue when reconstructing weights and activations separately during quantization and introduce a joint reconstruction method to resolve this problem. (2) We discover that Post-GELU activations are particularly sensitive to quantization due to their significant variability across different denoising steps as well as extreme asymmetries and variations within each step. To address this, we propose time-variance-aware transformations to facilitate more effective quantization. Experimental results show that when quantizing DiTs' weights to 4-bit and activations to 8-bit (W4A8), our method significantly surpasses previous quantization methods.
format Preprint
id arxiv_https___arxiv_org_abs_2411_14172
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle TaQ-DiT: Time-aware Quantization for Diffusion Transformers
Liu, Xinyan
Shi, Huihong
Xu, Yang
Wang, Zhongfeng
Image and Video Processing
Transformer-based diffusion models, dubbed Diffusion Transformers (DiTs), have achieved state-of-the-art performance in image and video generation tasks. However, their large model size and slow inference speed limit their practical applications, calling for model compression methods such as quantization. Unfortunately, existing DiT quantization methods overlook (1) the impact of reconstruction and (2) the varying quantization sensitivities across different layers, which hinder their achievable performance. To tackle these issues, we propose innovative time-aware quantization for DiTs (TaQ-DiT). Specifically, (1) we observe a non-convergence issue when reconstructing weights and activations separately during quantization and introduce a joint reconstruction method to resolve this problem. (2) We discover that Post-GELU activations are particularly sensitive to quantization due to their significant variability across different denoising steps as well as extreme asymmetries and variations within each step. To address this, we propose time-variance-aware transformations to facilitate more effective quantization. Experimental results show that when quantizing DiTs' weights to 4-bit and activations to 8-bit (W4A8), our method significantly surpasses previous quantization methods.
title TaQ-DiT: Time-aware Quantization for Diffusion Transformers
topic Image and Video Processing
url https://arxiv.org/abs/2411.14172