Getting the most out of your tokenizer for pre-training and domain adaptation

Fuente: arXiv
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Auteurs principaux: Dagan, Gautier, Synnaeve, Gabriel, Rozière, Baptiste
Format: Preprint
Publié: 2024
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author Dagan, Gautier
Synnaeve, Gabriel
Rozière, Baptiste
author_facet Dagan, Gautier
Synnaeve, Gabriel
Rozière, Baptiste
contents Tokenization is an understudied and often neglected component of modern LLMs. Most published works use a single tokenizer for all experiments, often borrowed from another model, without performing ablations or analysis to optimize tokenization. Moreover, the tokenizer is generally kept unchanged when fine-tuning a base model. In this paper, we show that the size, pre-tokenization regular expression, and training data of a tokenizer can significantly impact the model's generation speed, effective context size, memory usage, and downstream performance. We train specialized Byte-Pair Encoding code tokenizers, and conduct extensive ablations on the impact of tokenizer design on the performance of LLMs for code generation tasks such as HumanEval and MBPP, and provide recommendations for tokenizer hyper-parameters selection and switching the tokenizer in a pre-trained LLM. We perform our experiments on models trained from scratch and from pre-trained models, verifying their applicability to a wide range of use-cases. We find that when fine-tuning on more than 50 billion tokens, we can specialize the tokenizer of a pre-trained LLM to obtain large gains in generation speed and effective context size.
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id arxiv_https___arxiv_org_abs_2402_01035
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Getting the most out of your tokenizer for pre-training and domain adaptation
Dagan, Gautier
Synnaeve, Gabriel
Rozière, Baptiste
Computation and Language
Tokenization is an understudied and often neglected component of modern LLMs. Most published works use a single tokenizer for all experiments, often borrowed from another model, without performing ablations or analysis to optimize tokenization. Moreover, the tokenizer is generally kept unchanged when fine-tuning a base model. In this paper, we show that the size, pre-tokenization regular expression, and training data of a tokenizer can significantly impact the model's generation speed, effective context size, memory usage, and downstream performance. We train specialized Byte-Pair Encoding code tokenizers, and conduct extensive ablations on the impact of tokenizer design on the performance of LLMs for code generation tasks such as HumanEval and MBPP, and provide recommendations for tokenizer hyper-parameters selection and switching the tokenizer in a pre-trained LLM. We perform our experiments on models trained from scratch and from pre-trained models, verifying their applicability to a wide range of use-cases. We find that when fine-tuning on more than 50 billion tokens, we can specialize the tokenizer of a pre-trained LLM to obtain large gains in generation speed and effective context size.
title Getting the most out of your tokenizer for pre-training and domain adaptation
topic Computation and Language
url https://arxiv.org/abs/2402.01035