Efficient On-Device Diffusion LLM Inference with Mobile NPU

Abstract:Diffusion large language models (dLLMs) accelerate generation by denoising multiple tokens in parallel, making them attractive for latency-sensitive mobile inference. However, repeated denoising introduces substantial computation on smartphones. Mobile neural processing units (NPUs) offer high-throughput dense matrix computation, but efficiently exploiting them remains challenging: token commitment shrinks per-block effective workloads, token revision complicates KV cache reuse, and limited NPU-visible address space incurs costly remapping and data transfer overheads. In this paper, we propose this http URL, the first NPU-aware inference framework for accelerating dLLMs on smartphones. this http URL aligns block-wise dLLM inference with the execution characteristics of mobile NPUs through three techniques. (1) Multi-Block Speculative Decoding fills the shrinking workload in late-stage current-block decoding with speculative future-block tokens. (2) Dual-Path Progressive Revision keeps committed tokens revisable until stable and refreshes unstable tokens through a CPU-side path without stalling dense NPU execution. (3) Swap-Optimized Memory Runtime compacts NPU-visible address layouts and overlaps data staging with NPU computation to reduce remapping and transfer overheads. We implement this http URL as an end-to-end framework and evaluate it across diverse hardware platforms and dLLM workloads. this http URL reduces LLaDA-8B generation latency by 17x-42x over the CPU baseline with prefix KV cache reuse, while preserving generation quality.

Machine Learning (cs.LG)

arXiv:2606.13740 [cs.LG]

(or arXiv:2606.13740v1 [cs.LG] for this version)

https://doi.org/10.48550/arXiv.2606.13740 Focus to learn more arXiv-issued DOI via DataCite

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