To FP8 and Back Again: Quantifying Reduced Precision Effects on LLM Training Stability

Fuente: arXiv
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Main Authors: Lee, Joonhyung, Bae, Jeongin, Kim, Byeongwook, Kwon, Se Jung, Lee, Dongsoo
Format: Preprint
Published: 2024
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author Lee, Joonhyung
Bae, Jeongin
Kim, Byeongwook
Kwon, Se Jung
Lee, Dongsoo
author_facet Lee, Joonhyung
Bae, Jeongin
Kim, Byeongwook
Kwon, Se Jung
Lee, Dongsoo
contents The massive computational costs associated with large language model (LLM) pretraining have spurred great interest in reduced-precision floating-point representations to accelerate the process. As a result, the BrainFloat16 (BF16) precision has become the de facto standard for LLM training, with hardware support included in recent generations of accelerators. This trend has gone even further in the latest processors, where FP8 has recently been introduced. However, prior experience with FP16, which was found to be less stable than BF16, raises concerns as to whether FP8, with even fewer bits than FP16, can be a cost-effective option for LLM training. We argue that reduced-precision training schemes must have similar training stability and hyperparameter sensitivities to their higher-precision counterparts in order to be cost-effective. However, we find that currently available methods for FP8 training are not robust enough to allow their use as economical replacements. This prompts us to investigate the stability of reduced-precision LLM training in terms of robustness across random seeds, learning rates, and datasets. To this end, we propose new evaluation techniques and a new metric for quantifying loss landscape sharpness in autoregressive language models. By simulating incremental bit reductions in floating-point representations, we analyze the relationship between representational power and training stability with the intent of aiding future research into the field.
format Preprint
id arxiv_https___arxiv_org_abs_2405_18710
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle To FP8 and Back Again: Quantifying Reduced Precision Effects on LLM Training Stability
Lee, Joonhyung
Bae, Jeongin
Kim, Byeongwook
Kwon, Se Jung
Lee, Dongsoo
Machine Learning
Artificial Intelligence
The massive computational costs associated with large language model (LLM) pretraining have spurred great interest in reduced-precision floating-point representations to accelerate the process. As a result, the BrainFloat16 (BF16) precision has become the de facto standard for LLM training, with hardware support included in recent generations of accelerators. This trend has gone even further in the latest processors, where FP8 has recently been introduced. However, prior experience with FP16, which was found to be less stable than BF16, raises concerns as to whether FP8, with even fewer bits than FP16, can be a cost-effective option for LLM training. We argue that reduced-precision training schemes must have similar training stability and hyperparameter sensitivities to their higher-precision counterparts in order to be cost-effective. However, we find that currently available methods for FP8 training are not robust enough to allow their use as economical replacements. This prompts us to investigate the stability of reduced-precision LLM training in terms of robustness across random seeds, learning rates, and datasets. To this end, we propose new evaluation techniques and a new metric for quantifying loss landscape sharpness in autoregressive language models. By simulating incremental bit reductions in floating-point representations, we analyze the relationship between representational power and training stability with the intent of aiding future research into the field.
title To FP8 and Back Again: Quantifying Reduced Precision Effects on LLM Training Stability
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2405.18710