# Learning to Parallel: Accelerating Diffusion Large Language Models via Learnable Parallel Decoding

arXiv: https://arxiv.org/abs/2509.25188 · HTML: https://mlsanity.com/paper/2509.25188/

## Key facts

- Cited by 27 papers in the map (data through 14 Oct 2026).
- Placed in Diffusion LLM and MoE inference, one of 12 directions in Efficient LLM inference and serving.
- Builds on 37 of its 41 references that are in the map.
- First posted on arXiv 29 Sep 2025.

## Placed in

- Efficient LLM inference and serving / [Diffusion LLM and MoE inference](https://mlsanity.com/inference/diffusion-llm-and-moe-inference/)

## Builds on (most cited first, 30 of 37)

- [Attention Is All You Need](https://mlsanity.com/paper/1706.03762/) (2017)
- [BERT: Pre-training of Deep Bidirectional Transformers for Language Understanding](https://mlsanity.com/paper/1810.04805/) (2018)
- [Language Models are Few-Shot Learners](https://mlsanity.com/paper/2005.14165/) (2020)
- [Denoising Diffusion Probabilistic Models](https://mlsanity.com/paper/2006.11239/) (2020)
- [Training Verifiers to Solve Math Word Problems](https://mlsanity.com/paper/2110.14168/) (2021)
- [Denoising Diffusion Implicit Models](https://mlsanity.com/paper/2010.02502/) (2020)
- [Evaluating Large Language Models Trained on Code](https://mlsanity.com/paper/2107.03374/) (2021)
- [Deep Unsupervised Learning using Nonequilibrium Thermodynamics](https://mlsanity.com/paper/1503.03585/) (2015)
- [Improved Denoising Diffusion Probabilistic Models](https://mlsanity.com/paper/2102.09672/) (2021)
- [Program Synthesis with Large Language Models](https://mlsanity.com/paper/2108.07732/) (2021)
- [A Survey of Large Language Models](https://mlsanity.com/paper/2303.18223/) (2023)
- [Structured Denoising Diffusion Models in Discrete State-Spaces](https://mlsanity.com/paper/2107.03006/) (2021)
- [Fast Inference from Transformers via Speculative Decoding](https://mlsanity.com/paper/2211.17192/) (2022)
- [MLP-Mixer: An all-MLP Architecture for Vision](https://mlsanity.com/paper/2105.01601/) (2021)
- [Solving Quantitative Reasoning Problems with Language Models](https://mlsanity.com/paper/2206.14858/) (2022)
- [MaskGIT: Masked Generative Image Transformer](https://mlsanity.com/paper/2202.04200/) (2022)
- [Diffusion-LM Improves Controllable Text Generation](https://mlsanity.com/paper/2205.14217/) (2022)
- [Large Language Diffusion Models](https://mlsanity.com/paper/2502.09992/) (2025)
- [Simple and Effective Masked Diffusion Language Models](https://mlsanity.com/paper/2406.07524/) (2024)
- [Simplified and Generalized Masked Diffusion for Discrete Data](https://mlsanity.com/paper/2406.04329/) (2024)
- [Argmax Flows and Multinomial Diffusion: Learning Categorical Distributions](https://mlsanity.com/paper/2102.05379/) (2021)
- [Dream 7B: Diffusion Large Language Models](https://mlsanity.com/paper/2508.15487/) (2025)
- [Large Language Models: A Survey](https://mlsanity.com/paper/2402.06196/) (2024)
- [A Continuous Time Framework for Discrete Denoising Models](https://mlsanity.com/paper/2205.14987/) (2022)
- [Fast-dLLM: Training-free Acceleration of Diffusion LLM by Enabling KV Cache and Parallel Decoding](https://mlsanity.com/paper/2505.22618/) (2025)
- [Block Diffusion: Interpolating Between Autoregressive and Diffusion Language Models](https://mlsanity.com/paper/2503.09573/) (2025)
- [Your Absorbing Discrete Diffusion Secretly Models the Conditional Distributions of Clean Data](https://mlsanity.com/paper/2406.03736/) (2024)
- [Blockwise Parallel Decoding for Deep Autoregressive Models](https://mlsanity.com/paper/1811.03115/) (2018)
- [Scaling Diffusion Language Models via Adaptation from Autoregressive Models](https://mlsanity.com/paper/2410.17891/) (2024)
- [Masked Diffusion Models are Secretly Time-Agnostic Masked Models and Exploit Inaccurate Categorical Sampling](https://mlsanity.com/paper/2409.02908/) (2024)

## Built on by (most cited first, 27 of 27)

- [DAPD: Dependency-Aware Parallel Decoding via Attention for Diffusion LLMs](https://mlsanity.com/paper/2603.12996/) (2026)
- [Beyond Hard Masks: Progressive Token Evolution for Diffusion Language Models](https://mlsanity.com/paper/2601.07351/) (2026)
- [LightningRL: Breaking the Accuracy-Parallelism Trade-off of Block-wise dLLMs via Reinforcement Learning](https://mlsanity.com/paper/2603.13319/) (2026)
- [FOCUS: DLLMs Know How to Tame Their Compute Bound](https://mlsanity.com/paper/2601.23278/) (2026)
- [Locally Coherent Parallel Decoding in Diffusion Language Models](https://mlsanity.com/paper/2603.20216/) (2026)
- [TAD: Temporal-Aware Trajectory Self-Distillation for Fast and Accurate Diffusion LLM](https://mlsanity.com/paper/2605.09536/) (2026)
- [TIDE: Efficient and Lossless MoE Diffusion LLM Inference with I/O-aware Expert Offload](https://mlsanity.com/paper/2605.20179/) (2026)
- [Attention-Discounted Adaptive Sampler for Masked Diffusion Language Models](https://mlsanity.com/paper/2606.10829/) (2026)
- [STDec: Spatio-Temporal Stability Guided Decoding for dLLMs](https://mlsanity.com/paper/2604.06330/) (2026)
- [The Path Matters: Learning a Token-Commitment Policy for Diffusion Language Models](https://mlsanity.com/paper/2605.24697/) (2026)
- [Efficient Diffusion LLMs via Temporal-Spatial Parallel Decoding and Confidence Extrapolation](https://mlsanity.com/paper/2605.30753/) (2026)
- [Beyond Fully Random Masking: Attention-Guided Denoising and Optimization for Diffusion Language Models](https://mlsanity.com/paper/2606.12273/) (2026)
- [Polestar: Drift-Aware Cache Calibration and Token Commitment for Efficient Inference of Diffusion LLMs](https://mlsanity.com/paper/2607.14107/) (2026)
- [Temporal Self-Distillation: Faster Inference in Discrete Diffusion Language Models](https://mlsanity.com/paper/2609.15177/) (2026)
- [Multi-Token Residual Prediction](https://mlsanity.com/paper/2605.18817/) (2026)
- [AsyncLane: Decoupling Refinement from Advancement in Diffusion Language Model Decoding](https://mlsanity.com/paper/2606.08411/) (2026)
- [Understanding Evaluation Illusion in Diffusion Large Language Models](https://mlsanity.com/paper/2606.29228/) (2026)
- [DC-Leap: Training-Free Acceleration of dLLMs via Draft-Guided Contiguous Leaping Decoding](https://mlsanity.com/paper/2607.20467/) (2026)
- [CORA-Diff: Confidence-Oriented Residual Acceptance for Efficient Diffusion Language Model Inference](https://mlsanity.com/paper/2608.11235/) (2026)
- [Accelerating Diffusion Language Models via Structured Suffix Modeling](https://mlsanity.com/paper/2608.23167/) (2026)
- [Prefix-Denoising Consistency: Test-Time Verification for Diffusion Language Models](https://mlsanity.com/paper/2608.25311/) (2026)
- [Dependency-Aware Revocable Decoding for Efficient Diffusion Large Language Model Inference](https://mlsanity.com/paper/2608.26574/) (2026)
- [Visual Information-Guided Parallel Decoding for Diffusion Multimodal Large Language Models](https://mlsanity.com/paper/2608.26580/) (2026)
- [Diffusion Language Models for Mobile Edge Agentic AI: Foundations, Applications, and Challenges](https://mlsanity.com/paper/2609.04778/) (2026)
- [Early-Bird Decoding: Accelerating Diffusion LLMs with Learnable Block Sizes and Parallel Sampling](https://mlsanity.com/paper/2609.16450/) (2026)
- [d-OPD: Future-Aware On-Policy Distillation for Block Diffusion Language Models](https://mlsanity.com/paper/2609.35362/) (2026)
- [Batch-Paced: Fixed-Budget Batch Decoding in Discrete Diffusion Language Models](https://mlsanity.com/paper/2610.17917/) (2026)

## Abstract (arXiv)

Autoregressive decoding in large language models (LLMs) requires O(n) sequential steps for n tokens, fundamentally limiting inference throughput. Recent diffusion-based LLMs (dLLMs) enable parallel token generation through iterative denoising. However, current parallel decoding strategies rely on fixed, input-agnostic heuristics (e.g., confidence thresholds), which fail to adapt to input-specific characteristics, resulting in suboptimal speed-quality trade-offs across diverse NLP tasks. In this work, we explore a more flexible and dynamic approach to parallel decoding. We propose Learning to Parallel Decode (Learn2PD), a framework that trains a lightweight and adaptive filter model to predict, for each token position, whether the current prediction matches the final output. This learned filter approximates an oracle parallel decoding strategy that unmasks tokens only when correctly predicted. Importantly, the filter model is learned in a post-training manner, requiring only a small amount of computation to optimize it (minute-level GPU time). Additionally, we introduce End-of-Text Prediction (EoTP) to detect decoding completion at the end of sequence, avoiding redundant decoding of padding tokens. Experiments on the LLaDA benchmark demonstrate that our method achieves up to 22.58× speedup without any performance drop, and up to 57.51× when combined with KV-Cache.