Publication Type
Conference Proceeding Article
Version
acceptedVersion
Publication Date
9-2026
Abstract
Tree-based speculative decoding accelerates autoregressive generation by verifying a branching tree of draft tokens in a single targetmodel forward pass. However, existing methods prioritize maximizing token-level likelihood or the number of accepted tokens while ignoring a critical “efficiency paradox”: the computational overhead of drafting and verifying big trees can grow super-linearly, particularly at scale. This often leads to negative wall-clock speedup when batch sizes increase or hardware saturation limits are reached. To address this, we propose SMART, a System-aware Marginal Analysis framework for Runtime Tree construction. SMART reformulates tree expansion as a hardware-aware optimization problem that directly maximizes end-toend speedup. By applying a principled marginal benefit–cost rule at inference time, SMART expands a node only when its marginal benefit– cost ratio exceeds the tree-level speedup. SMART is training-free and serves as a plug-and-play controller for existing frameworks like MSD and EAGLE. Extensive evaluations across three MLLMs (e.g., LLaVA, Qwen2-VL) and four LLMs (e.g., Llama-3.1, DeepSeek-R1) demonstrate that SMART consistently outperforms state-of-the-art baselines. It delivers an average additional speedup of 20.0% for MLLMs and 15.4% for LLMs across compute-bound batching regimes and diverse GPU architectures without performance loss
Keywords
Speculative decoding, Multimodal large language models
Discipline
Artificial Intelligence and Robotics
Research Areas
Intelligent Systems and Optimization
Areas of Excellence
Digital transformation
Publication
Proceedings of the 19th European Conference on Computer Vision, ECCV 2026, Malmö, Sweden, September 8-12
First Page
1
Last Page
23
Publisher
ECCV
City or Country
Malmö, Sweden
Citation
WANG, Lifu and ZHOU, Pan.
SMART: When is it actually worth expanding a speculative tree?. (2026). Proceedings of the 19th European Conference on Computer Vision, ECCV 2026, Malmö, Sweden, September 8-12. 1-23.
Available at: https://ink.library.smu.edu.sg/sis_research/11331
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