Speculative Decoding with CTC-based Draft Model for LLM Inference Acceleration

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Hauptverfasser: Wen, Zhuofan, Gui, Shangtong, Feng, Yang
Format: Preprint
Veröffentlicht: 2024
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author Wen, Zhuofan
Gui, Shangtong
Feng, Yang
author_facet Wen, Zhuofan
Gui, Shangtong
Feng, Yang
contents Inference acceleration of large language models (LLMs) has been put forward in many application scenarios and speculative decoding has shown its advantage in addressing inference acceleration. Speculative decoding usually introduces a draft model to assist the base LLM where the draft model produces drafts and the base LLM verifies the draft for acceptance or rejection. In this framework, the final inference speed is decided by the decoding speed of the draft model and the acceptance rate of the draft provided by the draft model. Currently the widely used draft models usually generate draft tokens for the next several positions in a non-autoregressive way without considering the correlations between draft tokens. Therefore, it has a high decoding speed but an unsatisfactory acceptance rate. In this paper, we focus on how to improve the performance of the draft model and aim to accelerate inference via a high acceptance rate. To this end, we propose a CTC-based draft model which strengthens the correlations between draft tokens during the draft phase, thereby generating higher-quality draft candidate sequences. Experiment results show that compared to strong baselines, the proposed method can achieve a higher acceptance rate and hence a faster inference speed.
format Preprint
id arxiv_https___arxiv_org_abs_2412_00061
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Speculative Decoding with CTC-based Draft Model for LLM Inference Acceleration
Wen, Zhuofan
Gui, Shangtong
Feng, Yang
Machine Learning
Artificial Intelligence
Computation and Language
Inference acceleration of large language models (LLMs) has been put forward in many application scenarios and speculative decoding has shown its advantage in addressing inference acceleration. Speculative decoding usually introduces a draft model to assist the base LLM where the draft model produces drafts and the base LLM verifies the draft for acceptance or rejection. In this framework, the final inference speed is decided by the decoding speed of the draft model and the acceptance rate of the draft provided by the draft model. Currently the widely used draft models usually generate draft tokens for the next several positions in a non-autoregressive way without considering the correlations between draft tokens. Therefore, it has a high decoding speed but an unsatisfactory acceptance rate. In this paper, we focus on how to improve the performance of the draft model and aim to accelerate inference via a high acceptance rate. To this end, we propose a CTC-based draft model which strengthens the correlations between draft tokens during the draft phase, thereby generating higher-quality draft candidate sequences. Experiment results show that compared to strong baselines, the proposed method can achieve a higher acceptance rate and hence a faster inference speed.
title Speculative Decoding with CTC-based Draft Model for LLM Inference Acceleration
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2412.00061