SPARe: Stacked Parallelism with Adaptive Reordering for Fault-Tolerant LLM Pretraining Systems with 100k+ GPUs

Fuente: arXiv
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Main Authors: Lee, Jin, Chen, Zhonghao, He, Xuhang, Underwood, Robert, Nicolae, Bogdan, Cappello, Franck, Lu, Xiaoyi, Di, Sheng, Zhang, Zheng
Format: Preprint
Published: 2026
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author Lee, Jin
Chen, Zhonghao
He, Xuhang
Underwood, Robert
Nicolae, Bogdan
Cappello, Franck
Lu, Xiaoyi
Di, Sheng
Zhang, Zheng
author_facet Lee, Jin
Chen, Zhonghao
He, Xuhang
Underwood, Robert
Nicolae, Bogdan
Cappello, Franck
Lu, Xiaoyi
Di, Sheng
Zhang, Zheng
contents In large-scale LLM pre-training systems with 100k+ GPUs, failures become the norm rather than the exception, and restart costs can dominate wall-clock training time. However, existing fault-tolerance mechanisms are largely unprepared for this restart-dominant regime. To address this challenge, we propose SPARe - Stacked Parallelism with Adaptive Reordering - a fault-tolerance framework that masks node failures during gradient synchronization by stacking redundant data shards across parallelism groups and adaptively reordering execution. SPARe achieves availability comparable to traditional replication while maintaining near-constant computation overhead of only 2~3x, even under high redundancy where traditional replication would require linearly inflating overhead. We derive closed-form expressions for endurable failure count and computation overhead, validate them via SimGrid-based discrete-event simulation, and jointly optimize redundancy and checkpointing to minimize time-to-train. At extreme scale with up to 600k GPUs, SPARe reduces time-to-train by 40~50% compared to traditional replication.
format Preprint
id arxiv_https___arxiv_org_abs_2603_00357
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle SPARe: Stacked Parallelism with Adaptive Reordering for Fault-Tolerant LLM Pretraining Systems with 100k+ GPUs
Lee, Jin
Chen, Zhonghao
He, Xuhang
Underwood, Robert
Nicolae, Bogdan
Cappello, Franck
Lu, Xiaoyi
Di, Sheng
Zhang, Zheng
Distributed, Parallel, and Cluster Computing
Systems and Control
In large-scale LLM pre-training systems with 100k+ GPUs, failures become the norm rather than the exception, and restart costs can dominate wall-clock training time. However, existing fault-tolerance mechanisms are largely unprepared for this restart-dominant regime. To address this challenge, we propose SPARe - Stacked Parallelism with Adaptive Reordering - a fault-tolerance framework that masks node failures during gradient synchronization by stacking redundant data shards across parallelism groups and adaptively reordering execution. SPARe achieves availability comparable to traditional replication while maintaining near-constant computation overhead of only 2~3x, even under high redundancy where traditional replication would require linearly inflating overhead. We derive closed-form expressions for endurable failure count and computation overhead, validate them via SimGrid-based discrete-event simulation, and jointly optimize redundancy and checkpointing to minimize time-to-train. At extreme scale with up to 600k GPUs, SPARe reduces time-to-train by 40~50% compared to traditional replication.
title SPARe: Stacked Parallelism with Adaptive Reordering for Fault-Tolerant LLM Pretraining Systems with 100k+ GPUs
topic Distributed, Parallel, and Cluster Computing
Systems and Control
url https://arxiv.org/abs/2603.00357