When Drafts Evolve: Speculative Decoding Meets Online Learning

Fuente: arXiv
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Autores principales: Qian, Yu-Yang, Wu, Hao-Cong, Fu, Yichao, Zhang, Hao, Zhao, Peng
Formato: Preprint
Publicado: 2026
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author Qian, Yu-Yang
Wu, Hao-Cong
Fu, Yichao
Zhang, Hao
Zhao, Peng
author_facet Qian, Yu-Yang
Wu, Hao-Cong
Fu, Yichao
Zhang, Hao
Zhao, Peng
contents Speculative decoding has emerged as a widely adopted paradigm for accelerating large language model inference, where a lightweight draft model rapidly generates candidate tokens that are then verified in parallel by a larger target model. However, due to limited model capacity, drafts often struggle to approximate the target distribution, resulting in shorter acceptance lengths and diminished speedup. A key yet under-explored observation is that speculative decoding inherently provides verification feedback that quantifies the deviation between the draft and target models at no additional cost. This process naturally forms an iterative "draft commits-feedback provides-draft adapts" evolving loop, which precisely matches the online learning paradigm. Motivated by this connection, we propose OnlineSpec, a unified framework that systematically leverages interactive feedback to continuously evolve draft models. Grounded in dynamic regret minimization, we establish a formal link between online learning performance and speculative system's acceleration rate, and develop novel algorithms via modern online learning techniques, including optimistic online learning that adaptively reuses historical gradients as predictive update hints, and online ensemble learning that dynamically maintains multiple draft models. Our algorithms are equipped with theoretical justifications and improved acceleration rates, achieving up to 24% speedup over seven benchmarks and three foundation models.
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id arxiv_https___arxiv_org_abs_2603_12617
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publishDate 2026
record_format arxiv
spellingShingle When Drafts Evolve: Speculative Decoding Meets Online Learning
Qian, Yu-Yang
Wu, Hao-Cong
Fu, Yichao
Zhang, Hao
Zhao, Peng
Machine Learning
Artificial Intelligence
Speculative decoding has emerged as a widely adopted paradigm for accelerating large language model inference, where a lightweight draft model rapidly generates candidate tokens that are then verified in parallel by a larger target model. However, due to limited model capacity, drafts often struggle to approximate the target distribution, resulting in shorter acceptance lengths and diminished speedup. A key yet under-explored observation is that speculative decoding inherently provides verification feedback that quantifies the deviation between the draft and target models at no additional cost. This process naturally forms an iterative "draft commits-feedback provides-draft adapts" evolving loop, which precisely matches the online learning paradigm. Motivated by this connection, we propose OnlineSpec, a unified framework that systematically leverages interactive feedback to continuously evolve draft models. Grounded in dynamic regret minimization, we establish a formal link between online learning performance and speculative system's acceleration rate, and develop novel algorithms via modern online learning techniques, including optimistic online learning that adaptively reuses historical gradients as predictive update hints, and online ensemble learning that dynamically maintains multiple draft models. Our algorithms are equipped with theoretical justifications and improved acceleration rates, achieving up to 24% speedup over seven benchmarks and three foundation models.
title When Drafts Evolve: Speculative Decoding Meets Online Learning
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2603.12617