Original title: Unlocking Lossless Speedups in LLMs via Discrete Diffusion
Subham Sekhar Sahoo, Lingjie Chen, Khiem Pham, Jonathan Geuter +13 · September 2026
Large Language Models, or LLMs, usually create text one piece at a time. This slow, sequential step is called autoregressive generation. Because each word depends on the one right before it, making long texts takes a lot of time. To solve this bottleneck, researchers created Uno. Uno splits its setup into two parts: standard weights that predict the next token, and lightweight diffusion weights that draw multiple tokens in parallel from that same distribution. The diffusion weights are trained with a quick step called Diffusion Distillation, which adds negligible overhead to standard training. Uno uses a sampler called $Ψ$-Spec to speed up generation without losing any output quality. Unlike older shortcuts, it does not need a separate draft model. Uno achieves up to 3× speedups over base models, beats top speculative-decoding methods in throughput, and beats larger systems in coding, tool use, and long reasoning.
Imagine cooking a meal where you add ingredients one by one, stirring after each. It takes time because you must wait for each addition. Here, the researchers let you add several ingredients at once in the right combination, making the meal faster to prepare without ruining the taste.
This means language models can work much faster, saving time and energy for everyone from students to companies using AI tools. Faster generation allows for more responsive applications and real-time interactions.
The abstract does not specify limitations, but it focuses on speedups and benchmark performance without discussing training costs, compatibility with all LLM architectures, or performance on non-English languages.
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Unlocking Lossless Speedups in LLMs via Discrete Diffusion — Subham Sekhar Sahoo, Lingjie Chen, Khiem Pham et al.
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.