Resolving Discrepancies in Compute-Optimal Scaling of Language Models

Fuente: arXiv
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Autores principales: Porian, Tomer, Wortsman, Mitchell, Jitsev, Jenia, Schmidt, Ludwig, Carmon, Yair
Formato: Preprint
Publicado: 2024
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author Porian, Tomer
Wortsman, Mitchell
Jitsev, Jenia
Schmidt, Ludwig
Carmon, Yair
author_facet Porian, Tomer
Wortsman, Mitchell
Jitsev, Jenia
Schmidt, Ludwig
Carmon, Yair
contents Kaplan et al. and Hoffmann et al. developed influential scaling laws for the optimal model size as a function of the compute budget, but these laws yield substantially different predictions. We explain the discrepancy by reproducing the Kaplan scaling law on two datasets (OpenWebText2 and RefinedWeb) and identifying three factors causing the difference: last layer computational cost, warmup duration, and scale-dependent optimizer tuning. With these factors corrected, we obtain excellent agreement with the Hoffmann et al. (i.e., "Chinchilla") scaling law. Counter to a hypothesis of Hoffmann et al., we find that careful learning rate decay is not essential for the validity of their scaling law. As a secondary result, we derive scaling laws for the optimal learning rate and batch size, finding that tuning the AdamW $β_2$ parameter is essential at lower batch sizes.
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id arxiv_https___arxiv_org_abs_2406_19146
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Resolving Discrepancies in Compute-Optimal Scaling of Language Models
Porian, Tomer
Wortsman, Mitchell
Jitsev, Jenia
Schmidt, Ludwig
Carmon, Yair
Machine Learning
Computation and Language
Kaplan et al. and Hoffmann et al. developed influential scaling laws for the optimal model size as a function of the compute budget, but these laws yield substantially different predictions. We explain the discrepancy by reproducing the Kaplan scaling law on two datasets (OpenWebText2 and RefinedWeb) and identifying three factors causing the difference: last layer computational cost, warmup duration, and scale-dependent optimizer tuning. With these factors corrected, we obtain excellent agreement with the Hoffmann et al. (i.e., "Chinchilla") scaling law. Counter to a hypothesis of Hoffmann et al., we find that careful learning rate decay is not essential for the validity of their scaling law. As a secondary result, we derive scaling laws for the optimal learning rate and batch size, finding that tuning the AdamW $β_2$ parameter is essential at lower batch sizes.
title Resolving Discrepancies in Compute-Optimal Scaling of Language Models
topic Machine Learning
Computation and Language
url https://arxiv.org/abs/2406.19146