Diffusion LLMs Can Do Faster-Than-AR Inference via Discrete Diffusion Forcing

Fuente: arXiv
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Autori principali: Wang, Xu, Xu, Chenkai, Jin, Yijie, Jin, Jiachun, Zhang, Hao, Deng, Zhijie
Natura: Preprint
Pubblicazione: 2025
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author Wang, Xu
Xu, Chenkai
Jin, Yijie
Jin, Jiachun
Zhang, Hao
Deng, Zhijie
author_facet Wang, Xu
Xu, Chenkai
Jin, Yijie
Jin, Jiachun
Zhang, Hao
Deng, Zhijie
contents Diffusion Large Language Models (dLLMs) have emerged as a promising alternative to autoregressive (AR) LLMs for text generation, with the potential to decode multiple tokens in a single iteration. However, none of the existing open-source dLLMs have achieved superior inference speed over AR LLMs of similar size. This paper breaks this barrier based on a simple and effective strategy named discrete diffusion forcing (D2F). D2F equips dLLMs with two key capabilities: (1) block-wise autoregressive generation to enable KV cache utilization; (2) prediction of following tokens without requiring completion of prior blocks for inter-block parallel decoding. In this way, the vanilla dLLMs are refurbished into an AR-diffusion hybrid paradigm for efficient inference. D2F can be implemented with an asymmetric distillation process based on pre-trained dLLMs. We further propose a pipelined parallel decoding algorithm, which enables a trade-off between efficiency and efficacy. Empirically, D2F dLLMs achieve more than $\mathbf{2.5\times}$ inference speed than LLaMA3 and Qwen2.5 on GSM8K. Compared to vanilla dLLMs like LLaDA and Dream, the acceleration can be more than $\mathbf{50\times}$ while maintaining comparable output quality. The code is available at https://github.com/zhijie-group/Discrete-Diffusion-Forcing.
format Preprint
id arxiv_https___arxiv_org_abs_2508_09192
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Diffusion LLMs Can Do Faster-Than-AR Inference via Discrete Diffusion Forcing
Wang, Xu
Xu, Chenkai
Jin, Yijie
Jin, Jiachun
Zhang, Hao
Deng, Zhijie
Machine Learning
Artificial Intelligence
Diffusion Large Language Models (dLLMs) have emerged as a promising alternative to autoregressive (AR) LLMs for text generation, with the potential to decode multiple tokens in a single iteration. However, none of the existing open-source dLLMs have achieved superior inference speed over AR LLMs of similar size. This paper breaks this barrier based on a simple and effective strategy named discrete diffusion forcing (D2F). D2F equips dLLMs with two key capabilities: (1) block-wise autoregressive generation to enable KV cache utilization; (2) prediction of following tokens without requiring completion of prior blocks for inter-block parallel decoding. In this way, the vanilla dLLMs are refurbished into an AR-diffusion hybrid paradigm for efficient inference. D2F can be implemented with an asymmetric distillation process based on pre-trained dLLMs. We further propose a pipelined parallel decoding algorithm, which enables a trade-off between efficiency and efficacy. Empirically, D2F dLLMs achieve more than $\mathbf{2.5\times}$ inference speed than LLaMA3 and Qwen2.5 on GSM8K. Compared to vanilla dLLMs like LLaDA and Dream, the acceleration can be more than $\mathbf{50\times}$ while maintaining comparable output quality. The code is available at https://github.com/zhijie-group/Discrete-Diffusion-Forcing.
title Diffusion LLMs Can Do Faster-Than-AR Inference via Discrete Diffusion Forcing
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2508.09192