LoPA: Scaling dLLM Inference via Lookahead Parallel Decoding

Fuente: arXiv
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Main Authors: Xu, Chenkai, Jin, Yijie, Li, Jiajun, Tu, Yi, Long, Guoping, Tu, Dandan, Song, Mingcong, Si, Hongjie, Hou, Tianqi, Yan, Junchi, Deng, Zhijie
Format: Preprint
Published: 2025
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author Xu, Chenkai
Jin, Yijie
Li, Jiajun
Tu, Yi
Long, Guoping
Tu, Dandan
Song, Mingcong
Si, Hongjie
Hou, Tianqi
Yan, Junchi
Deng, Zhijie
author_facet Xu, Chenkai
Jin, Yijie
Li, Jiajun
Tu, Yi
Long, Guoping
Tu, Dandan
Song, Mingcong
Si, Hongjie
Hou, Tianqi
Yan, Junchi
Deng, Zhijie
contents Diffusion Large Language Models (dLLMs) have demonstrated significant potential for high-speed inference. However, current confidence-driven decoding strategies are constrained by limited parallelism, typically achieving only 1--3 tokens per forward pass (TPF). In this work, we identify that the degree of parallelism during dLLM inference is highly sensitive to the Token Filling Order (TFO). Then, we introduce Lookahead PArallel Decoding LoPA, a training-free, plug-and-play algorithm, to identify a superior TFO and hence accelerate inference. LoPA concurrently explores distinct candidate TFOs via parallel branches, and selects the one with the highest potential for future parallelism based on branch confidence. We apply LoPA to the state-of-the-art D2F model and observe a substantial enhancement in decoding efficiency. Notably, LoPA increases the TPF of D2F-Dream to 10.1 on the GSM8K while maintaining performance superior to the Dream baseline. Furthermore, to facilitate this unprecedented degree of parallelism, we develop a specialized multi-device inference system featuring Branch Parallelism (BP), which achieves a single-sample throughput of 1073.9 tokens per second under multi-GPU deployment. The code is available at https://github.com/zhijie-group/LoPA.
format Preprint
id arxiv_https___arxiv_org_abs_2512_16229
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle LoPA: Scaling dLLM Inference via Lookahead Parallel Decoding
Xu, Chenkai
Jin, Yijie
Li, Jiajun
Tu, Yi
Long, Guoping
Tu, Dandan
Song, Mingcong
Si, Hongjie
Hou, Tianqi
Yan, Junchi
Deng, Zhijie
Computation and Language
Diffusion Large Language Models (dLLMs) have demonstrated significant potential for high-speed inference. However, current confidence-driven decoding strategies are constrained by limited parallelism, typically achieving only 1--3 tokens per forward pass (TPF). In this work, we identify that the degree of parallelism during dLLM inference is highly sensitive to the Token Filling Order (TFO). Then, we introduce Lookahead PArallel Decoding LoPA, a training-free, plug-and-play algorithm, to identify a superior TFO and hence accelerate inference. LoPA concurrently explores distinct candidate TFOs via parallel branches, and selects the one with the highest potential for future parallelism based on branch confidence. We apply LoPA to the state-of-the-art D2F model and observe a substantial enhancement in decoding efficiency. Notably, LoPA increases the TPF of D2F-Dream to 10.1 on the GSM8K while maintaining performance superior to the Dream baseline. Furthermore, to facilitate this unprecedented degree of parallelism, we develop a specialized multi-device inference system featuring Branch Parallelism (BP), which achieves a single-sample throughput of 1073.9 tokens per second under multi-GPU deployment. The code is available at https://github.com/zhijie-group/LoPA.
title LoPA: Scaling dLLM Inference via Lookahead Parallel Decoding
topic Computation and Language
url https://arxiv.org/abs/2512.16229