Aioli: A Unified Optimization Framework for Language Model Data Mixing

Fuente: arXiv
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Main Authors: Chen, Mayee F., Hu, Michael Y., Lourie, Nicholas, Cho, Kyunghyun, Ré, Christopher
Format: Preprint
Published: 2024
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author Chen, Mayee F.
Hu, Michael Y.
Lourie, Nicholas
Cho, Kyunghyun
Ré, Christopher
author_facet Chen, Mayee F.
Hu, Michael Y.
Lourie, Nicholas
Cho, Kyunghyun
Ré, Christopher
contents Language model performance depends on identifying the optimal mixture of data groups to train on (e.g., law, code, math). Prior work has proposed a diverse set of methods to efficiently learn mixture proportions, ranging from fitting regression models over training runs to dynamically updating proportions throughout training. Surprisingly, we find that no existing method consistently outperforms a simple stratified sampling baseline in terms of average test perplexity. To understand this inconsistency, we unify existing methods into a standard framework, showing they are equivalent to solving a common optimization problem: minimize average loss subject to a method-specific mixing law -- an implicit assumption on the relationship between loss and mixture proportions. This framework suggests that measuring the fidelity of a method's mixing law can offer insights into its performance. Empirically, we find that existing methods set their mixing law parameters inaccurately, resulting in the inconsistent mixing performance we observe. Using this insight, we derive a new online method named Aioli, which directly estimates the mixing law parameters throughout training and uses them to dynamically adjust proportions. Aioli outperforms stratified sampling on 6 out of 6 datasets by an average of 0.27 test perplexity points, whereas existing methods fail to consistently beat stratified sampling, doing up to 6.9 points worse. Moreover, in a practical setting where proportions are learned on shorter runs due to computational constraints, Aioli can dynamically adjust these proportions over the full training run, consistently improving performance over existing methods by up to 12.012 test perplexity points.
format Preprint
id arxiv_https___arxiv_org_abs_2411_05735
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Aioli: A Unified Optimization Framework for Language Model Data Mixing
Chen, Mayee F.
Hu, Michael Y.
Lourie, Nicholas
Cho, Kyunghyun
Ré, Christopher
Machine Learning
Artificial Intelligence
Computation and Language
Language model performance depends on identifying the optimal mixture of data groups to train on (e.g., law, code, math). Prior work has proposed a diverse set of methods to efficiently learn mixture proportions, ranging from fitting regression models over training runs to dynamically updating proportions throughout training. Surprisingly, we find that no existing method consistently outperforms a simple stratified sampling baseline in terms of average test perplexity. To understand this inconsistency, we unify existing methods into a standard framework, showing they are equivalent to solving a common optimization problem: minimize average loss subject to a method-specific mixing law -- an implicit assumption on the relationship between loss and mixture proportions. This framework suggests that measuring the fidelity of a method's mixing law can offer insights into its performance. Empirically, we find that existing methods set their mixing law parameters inaccurately, resulting in the inconsistent mixing performance we observe. Using this insight, we derive a new online method named Aioli, which directly estimates the mixing law parameters throughout training and uses them to dynamically adjust proportions. Aioli outperforms stratified sampling on 6 out of 6 datasets by an average of 0.27 test perplexity points, whereas existing methods fail to consistently beat stratified sampling, doing up to 6.9 points worse. Moreover, in a practical setting where proportions are learned on shorter runs due to computational constraints, Aioli can dynamically adjust these proportions over the full training run, consistently improving performance over existing methods by up to 12.012 test perplexity points.
title Aioli: A Unified Optimization Framework for Language Model Data Mixing
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2411.05735