@inproceedings{wu-etal-2026-blockbatch,
title = "{B}lock{B}atch: Multi-Scale Consensus Decoding for Efficient Diffusion Language Model Inference",
author = "Wu, Xiaoyou and
Shih, Cheng-Jhih and
Ji, Binfei and
Liu, Yong and
Lin, Yingyan Celine",
editor = "Lee, Hung-Yi and
Dev, Sunipa and
Li, Jessy and
Elliott, Desmond",
booktitle = "Findings of the {A}ssociation for {C}omputational {L}inguistics: {EMNLP} 2026",
month = oct,
year = "2026",
address = "Budapest, Hungary",
publisher = "Association for Computational Linguistics",
url = "https://aclanthology.org/2026.findings-emnlp.1492/",
pages = "31747--31774",
ISBN = "979-8-89176-462-0",
abstract = "Diffusion language models (dLLMs) generate text by iteratively denoising multiple token positions in parallel, offering an attractive alternative to strictly autoregressive decoding. In practice, however, block-wise dLLM inference exposes a difficult granularity trade-off: small blocks preserve local conditioning but require many denoising steps, whereas large blocks expose more parallelism but can make premature commitments. Existing block-wise acceleration methods either use a fixed block size or adapt block boundaries along a single decoding trajectory, leaving the complementarity among concurrently executed block-size trajectories unused. We show that block-size diversity provides a useful branching dimension. Different block sizes induce related but non-identical KV-cache trajectories: branches often share an initial prefix, bifurcate at semantically decisive positions, and later agree on syntactically lightweight tokens. Motivated by this structure, we propose BlockBatch, a training-free online inference framework that executes multiple block-size branches for the same request inside a batched forward pass. BlockBatch coordinates these branches through confidence-gated token merging, leader-based synchronization, and periodic full-sequence refreshes that re-anchor local block updates to a globally consistent KV state. Across three representative dLLMs and four datasets, BlockBatch reduces denoising NFEs by 26.6{\%} on average and achieves a 1.33$\times$ average end-to-end speedup, with comparable average accuracy."
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<abstract>Diffusion language models (dLLMs) generate text by iteratively denoising multiple token positions in parallel, offering an attractive alternative to strictly autoregressive decoding. In practice, however, block-wise dLLM inference exposes a difficult granularity trade-off: small blocks preserve local conditioning but require many denoising steps, whereas large blocks expose more parallelism but can make premature commitments. Existing block-wise acceleration methods either use a fixed block size or adapt block boundaries along a single decoding trajectory, leaving the complementarity among concurrently executed block-size trajectories unused. We show that block-size diversity provides a useful branching dimension. Different block sizes induce related but non-identical KV-cache trajectories: branches often share an initial prefix, bifurcate at semantically decisive positions, and later agree on syntactically lightweight tokens. Motivated by this structure, we propose BlockBatch, a training-free online inference framework that executes multiple block-size branches for the same request inside a batched forward pass. BlockBatch coordinates these branches through confidence-gated token merging, leader-based synchronization, and periodic full-sequence refreshes that re-anchor local block updates to a globally consistent KV state. Across three representative dLLMs and four datasets, BlockBatch reduces denoising NFEs by 26.6% on average and achieves a 1.33\times average end-to-end speedup, with comparable average accuracy.</abstract>
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%0 Conference Proceedings
%T BlockBatch: Multi-Scale Consensus Decoding for Efficient Diffusion Language Model Inference
%A Wu, Xiaoyou
%A Shih, Cheng-Jhih
%A Ji, Binfei
%A Liu, Yong
%A Lin, Yingyan Celine
%Y Lee, Hung-Yi
%Y Dev, Sunipa
%Y Li, Jessy
%Y Elliott, Desmond
%S Findings of the Association for Computational Linguistics: EMNLP 2026
%D 2026
%8 October
%I Association for Computational Linguistics
%C Budapest, Hungary
%@ 979-8-89176-462-0
%F wu-etal-2026-blockbatch
%X Diffusion language models (dLLMs) generate text by iteratively denoising multiple token positions in parallel, offering an attractive alternative to strictly autoregressive decoding. In practice, however, block-wise dLLM inference exposes a difficult granularity trade-off: small blocks preserve local conditioning but require many denoising steps, whereas large blocks expose more parallelism but can make premature commitments. Existing block-wise acceleration methods either use a fixed block size or adapt block boundaries along a single decoding trajectory, leaving the complementarity among concurrently executed block-size trajectories unused. We show that block-size diversity provides a useful branching dimension. Different block sizes induce related but non-identical KV-cache trajectories: branches often share an initial prefix, bifurcate at semantically decisive positions, and later agree on syntactically lightweight tokens. Motivated by this structure, we propose BlockBatch, a training-free online inference framework that executes multiple block-size branches for the same request inside a batched forward pass. BlockBatch coordinates these branches through confidence-gated token merging, leader-based synchronization, and periodic full-sequence refreshes that re-anchor local block updates to a globally consistent KV state. Across three representative dLLMs and four datasets, BlockBatch reduces denoising NFEs by 26.6% on average and achieves a 1.33\times average end-to-end speedup, with comparable average accuracy.
%U https://aclanthology.org/2026.findings-emnlp.1492/
%P 31747-31774
Markdown (Informal)
[BlockBatch: Multi-Scale Consensus Decoding for Efficient Diffusion Language Model Inference](https://aclanthology.org/2026.findings-emnlp.1492/) (Wu et al., Findings 2026)
ACL