Reward-Guided Speculative Decoding for Efficient LLM Reasoning

Fuente: arXiv
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Main Authors: Liao, Baohao, Xu, Yuhui, Dong, Hanze, Li, Junnan, Monz, Christof, Savarese, Silvio, Sahoo, Doyen, Xiong, Caiming
Format: Preprint
Published: 2025
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author Liao, Baohao
Xu, Yuhui
Dong, Hanze
Li, Junnan
Monz, Christof
Savarese, Silvio
Sahoo, Doyen
Xiong, Caiming
author_facet Liao, Baohao
Xu, Yuhui
Dong, Hanze
Li, Junnan
Monz, Christof
Savarese, Silvio
Sahoo, Doyen
Xiong, Caiming
contents We introduce Reward-Guided Speculative Decoding (RSD), a novel framework aimed at improving the efficiency of inference in large language models (LLMs). RSD synergistically combines a lightweight draft model with a more powerful target model, incorporating a controlled bias to prioritize high-reward outputs, in contrast to existing speculative decoding methods that enforce strict unbiasedness. RSD employs a process reward model to evaluate intermediate decoding steps and dynamically decide whether to invoke the target model, optimizing the trade-off between computational cost and output quality. We theoretically demonstrate that a threshold-based mixture strategy achieves an optimal balance between resource utilization and performance. Extensive evaluations on challenging reasoning benchmarks, including Olympiad-level tasks, show that RSD delivers significant efficiency gains against decoding with the target model only (up to 4.4x fewer FLOPs), while achieving significant better accuracy than parallel decoding method on average (up to +3.5). These results highlight RSD as a robust and cost-effective approach for deploying LLMs in resource-intensive scenarios. The code is available at https://github.com/BaohaoLiao/RSD.
format Preprint
id arxiv_https___arxiv_org_abs_2501_19324
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Reward-Guided Speculative Decoding for Efficient LLM Reasoning
Liao, Baohao
Xu, Yuhui
Dong, Hanze
Li, Junnan
Monz, Christof
Savarese, Silvio
Sahoo, Doyen
Xiong, Caiming
Computation and Language
Artificial Intelligence
We introduce Reward-Guided Speculative Decoding (RSD), a novel framework aimed at improving the efficiency of inference in large language models (LLMs). RSD synergistically combines a lightweight draft model with a more powerful target model, incorporating a controlled bias to prioritize high-reward outputs, in contrast to existing speculative decoding methods that enforce strict unbiasedness. RSD employs a process reward model to evaluate intermediate decoding steps and dynamically decide whether to invoke the target model, optimizing the trade-off between computational cost and output quality. We theoretically demonstrate that a threshold-based mixture strategy achieves an optimal balance between resource utilization and performance. Extensive evaluations on challenging reasoning benchmarks, including Olympiad-level tasks, show that RSD delivers significant efficiency gains against decoding with the target model only (up to 4.4x fewer FLOPs), while achieving significant better accuracy than parallel decoding method on average (up to +3.5). These results highlight RSD as a robust and cost-effective approach for deploying LLMs in resource-intensive scenarios. The code is available at https://github.com/BaohaoLiao/RSD.
title Reward-Guided Speculative Decoding for Efficient LLM Reasoning
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2501.19324