Optimizing Pre-Training Data Mixtures with Mixtures of Data Expert Models

Fuente: arXiv
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Auteurs principaux: Belenki, Lior, Agarwal, Alekh, Shi, Tianze, Toutanova, Kristina
Format: Preprint
Publié: 2025
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author Belenki, Lior
Agarwal, Alekh
Shi, Tianze
Toutanova, Kristina
author_facet Belenki, Lior
Agarwal, Alekh
Shi, Tianze
Toutanova, Kristina
contents We propose a method to optimize language model pre-training data mixtures through efficient approximation of the cross-entropy loss corresponding to each candidate mixture via a Mixture of Data Experts (MDE). We use this approximation as a source of additional features in a regression model, trained from observations of model loss for a small number of mixtures. Experiments with Transformer decoder-only language models in the range of 70M to 1B parameters on the SlimPajama dataset show that our method achieves significantly better performance than approaches that train regression models using only the mixture rates as input features. Combining this improved optimization method with an objective that takes into account cross-entropy on end task data leads to superior performance on few-shot downstream evaluations. We also provide theoretical insights on why aggregation of data expert predictions can provide good approximations to model losses for data mixtures.
format Preprint
id arxiv_https___arxiv_org_abs_2502_15950
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Optimizing Pre-Training Data Mixtures with Mixtures of Data Expert Models
Belenki, Lior
Agarwal, Alekh
Shi, Tianze
Toutanova, Kristina
Machine Learning
Computation and Language
We propose a method to optimize language model pre-training data mixtures through efficient approximation of the cross-entropy loss corresponding to each candidate mixture via a Mixture of Data Experts (MDE). We use this approximation as a source of additional features in a regression model, trained from observations of model loss for a small number of mixtures. Experiments with Transformer decoder-only language models in the range of 70M to 1B parameters on the SlimPajama dataset show that our method achieves significantly better performance than approaches that train regression models using only the mixture rates as input features. Combining this improved optimization method with an objective that takes into account cross-entropy on end task data leads to superior performance on few-shot downstream evaluations. We also provide theoretical insights on why aggregation of data expert predictions can provide good approximations to model losses for data mixtures.
title Optimizing Pre-Training Data Mixtures with Mixtures of Data Expert Models
topic Machine Learning
Computation and Language
url https://arxiv.org/abs/2502.15950