All is Not Lost: LLM Recovery without Checkpoints

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Main Authors: Blagoev, Nikolay, Ersoy, Oğuzhan, Chen, Lydia Yiyu
Format: Preprint
Published: 2025
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author Blagoev, Nikolay
Ersoy, Oğuzhan
Chen, Lydia Yiyu
author_facet Blagoev, Nikolay
Ersoy, Oğuzhan
Chen, Lydia Yiyu
contents Training LLMs on decentralized nodes or on-spot instances, lowers the training cost and enables model democratization. The inevitable challenge here is the transient churns of nodes due to failures and the operator's scheduling policies, leading to losing parts of the model (some layers). The conventional approaches to recover from failures is to either use checkpointing, where periodically a copy of the entire model is sent to an additional storage, or redundant computation. These approaches yield significant communication and/or computation overhead even in non-failure cases and scale poorly in settings with large models. In this paper we propose CheckFree, an efficient recovery method where a failing stage is substituted by weighted averaging of the closest neighboring stages. In contrast to the state of the art, CheckFree requires no additional computation or storage. However, because of the nature of averaging neighbouring stages, it can only recover failures of intermediate stages. We further extend our method to CheckFree+ with out-of-order pipeline execution to tolerate crashes of the first and last stages. Thanks to out-of-order pipelining, behaviour of the first and last stages are mimicked by their neighboring ones, which allows CheckFree+ to recover them by copying the neighboring stages. To recover the (de-)embedding layers, CheckFree+ copies those layers in the neighboring stages, which requires relatively small storage overhead. We extensively evaluate our method on LLaMa models of model sizes from 124M to 1.5B with varying failure frequencies. In the case of low and medium failure rates (5-10%), CheckFree and CheckFree+ outperform both checkpointing and redundant computation in terms of convergence wall-clock time, achieving up to 12% improvement over redundant computation. Both of our proposals can be ran via our code available at: https://github.com/gensyn-ai/CheckFree
format Preprint
id arxiv_https___arxiv_org_abs_2506_15461
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle All is Not Lost: LLM Recovery without Checkpoints
Blagoev, Nikolay
Ersoy, Oğuzhan
Chen, Lydia Yiyu
Distributed, Parallel, and Cluster Computing
Machine Learning
Training LLMs on decentralized nodes or on-spot instances, lowers the training cost and enables model democratization. The inevitable challenge here is the transient churns of nodes due to failures and the operator's scheduling policies, leading to losing parts of the model (some layers). The conventional approaches to recover from failures is to either use checkpointing, where periodically a copy of the entire model is sent to an additional storage, or redundant computation. These approaches yield significant communication and/or computation overhead even in non-failure cases and scale poorly in settings with large models. In this paper we propose CheckFree, an efficient recovery method where a failing stage is substituted by weighted averaging of the closest neighboring stages. In contrast to the state of the art, CheckFree requires no additional computation or storage. However, because of the nature of averaging neighbouring stages, it can only recover failures of intermediate stages. We further extend our method to CheckFree+ with out-of-order pipeline execution to tolerate crashes of the first and last stages. Thanks to out-of-order pipelining, behaviour of the first and last stages are mimicked by their neighboring ones, which allows CheckFree+ to recover them by copying the neighboring stages. To recover the (de-)embedding layers, CheckFree+ copies those layers in the neighboring stages, which requires relatively small storage overhead. We extensively evaluate our method on LLaMa models of model sizes from 124M to 1.5B with varying failure frequencies. In the case of low and medium failure rates (5-10%), CheckFree and CheckFree+ outperform both checkpointing and redundant computation in terms of convergence wall-clock time, achieving up to 12% improvement over redundant computation. Both of our proposals can be ran via our code available at: https://github.com/gensyn-ai/CheckFree
title All is Not Lost: LLM Recovery without Checkpoints
topic Distributed, Parallel, and Cluster Computing
Machine Learning
url https://arxiv.org/abs/2506.15461