CORAL: Learning Consistent Representations across Multi-step Training with Lighter Speculative Drafter

Fuente: arXiv
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Autori principali: Weng, Yepeng, Mei, Dianwen, Qiu, Huishi, Chen, Xujie, Liu, Li, Tian, Jiang, Shi, Zhongchao
Natura: Preprint
Pubblicazione: 2025
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author Weng, Yepeng
Mei, Dianwen
Qiu, Huishi
Chen, Xujie
Liu, Li
Tian, Jiang
Shi, Zhongchao
author_facet Weng, Yepeng
Mei, Dianwen
Qiu, Huishi
Chen, Xujie
Liu, Li
Tian, Jiang
Shi, Zhongchao
contents Speculative decoding is a powerful technique that accelerates Large Language Model (LLM) inference by leveraging a lightweight speculative draft model. However, existing designs suffers in performance due to misalignment between training and inference. Recent methods have tried to solve this issue by adopting a multi-step training strategy, but the complex inputs of different training steps make it harder for the draft model to converge. To address this, we propose CORAL, a novel framework that improves both accuracy and efficiency in speculative drafting. CORAL introduces Cross-Step Representation Alignment, a method that enhances consistency across multiple training steps, significantly improving speculative drafting performance. Additionally, we identify the LM head as a major bottleneck in the inference speed of the draft model. We introduce a weight-grouping mechanism that selectively activates a subset of LM head parameters during inference, substantially reducing the latency of the draft model. We evaluate CORAL on three LLM families and three benchmark datasets, achieving speedup ratios of 2.50x-4.07x, outperforming state-of-the-art methods such as EAGLE-2 and HASS. Our results demonstrate that CORAL effectively mitigates training-inference misalignment and delivers significant speedup for modern LLMs with large vocabularies.
format Preprint
id arxiv_https___arxiv_org_abs_2502_16880
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle CORAL: Learning Consistent Representations across Multi-step Training with Lighter Speculative Drafter
Weng, Yepeng
Mei, Dianwen
Qiu, Huishi
Chen, Xujie
Liu, Li
Tian, Jiang
Shi, Zhongchao
Computation and Language
Artificial Intelligence
Machine Learning
Speculative decoding is a powerful technique that accelerates Large Language Model (LLM) inference by leveraging a lightweight speculative draft model. However, existing designs suffers in performance due to misalignment between training and inference. Recent methods have tried to solve this issue by adopting a multi-step training strategy, but the complex inputs of different training steps make it harder for the draft model to converge. To address this, we propose CORAL, a novel framework that improves both accuracy and efficiency in speculative drafting. CORAL introduces Cross-Step Representation Alignment, a method that enhances consistency across multiple training steps, significantly improving speculative drafting performance. Additionally, we identify the LM head as a major bottleneck in the inference speed of the draft model. We introduce a weight-grouping mechanism that selectively activates a subset of LM head parameters during inference, substantially reducing the latency of the draft model. We evaluate CORAL on three LLM families and three benchmark datasets, achieving speedup ratios of 2.50x-4.07x, outperforming state-of-the-art methods such as EAGLE-2 and HASS. Our results demonstrate that CORAL effectively mitigates training-inference misalignment and delivers significant speedup for modern LLMs with large vocabularies.
title CORAL: Learning Consistent Representations across Multi-step Training with Lighter Speculative Drafter
topic Computation and Language
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2502.16880