Streaming DiLoCo with overlapping communication: Towards a Distributed Free Lunch

Fuente: arXiv
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Main Authors: Douillard, Arthur, Donchev, Yanislav, Rush, Keith, Kale, Satyen, Charles, Zachary, Garrett, Zachary, Teston, Gabriel, Lacey, Dave, McIlroy, Ross, Shen, Jiajun, Ramé, Alexandre, Szlam, Arthur, Ranzato, Marc'Aurelio, Barham, Paul
Format: Preprint
Published: 2025
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author Douillard, Arthur
Donchev, Yanislav
Rush, Keith
Kale, Satyen
Charles, Zachary
Garrett, Zachary
Teston, Gabriel
Lacey, Dave
McIlroy, Ross
Shen, Jiajun
Ramé, Alexandre
Szlam, Arthur
Ranzato, Marc'Aurelio
Barham, Paul
author_facet Douillard, Arthur
Donchev, Yanislav
Rush, Keith
Kale, Satyen
Charles, Zachary
Garrett, Zachary
Teston, Gabriel
Lacey, Dave
McIlroy, Ross
Shen, Jiajun
Ramé, Alexandre
Szlam, Arthur
Ranzato, Marc'Aurelio
Barham, Paul
contents Training of large language models (LLMs) is typically distributed across a large number of accelerators to reduce training time. Since internal states and parameter gradients need to be exchanged at each and every single gradient step, all devices need to be co-located using low-latency high-bandwidth communication links to support the required high volume of exchanged bits. Recently, distributed algorithms like DiLoCo have relaxed such co-location constraint: accelerators can be grouped into ``workers'', where synchronizations between workers only occur infrequently. This in turn means that workers can afford being connected by lower bandwidth communication links without affecting learning quality. However, in these methods, communication across workers still requires the same peak bandwidth as before, as the synchronizations require all parameters to be exchanged across all workers. In this paper, we improve DiLoCo in three ways. First, we synchronize only subsets of parameters in sequence, rather than all at once, which greatly reduces peak bandwidth. Second, we allow workers to continue training while synchronizing, which decreases wall clock time. Third, we quantize the data exchanged by workers, which further reduces bandwidth across workers. By properly combining these modifications, we show experimentally that we can distribute training of billion-scale parameters and reach similar quality as before, but reducing required bandwidth by two orders of magnitude.
format Preprint
id arxiv_https___arxiv_org_abs_2501_18512
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Streaming DiLoCo with overlapping communication: Towards a Distributed Free Lunch
Douillard, Arthur
Donchev, Yanislav
Rush, Keith
Kale, Satyen
Charles, Zachary
Garrett, Zachary
Teston, Gabriel
Lacey, Dave
McIlroy, Ross
Shen, Jiajun
Ramé, Alexandre
Szlam, Arthur
Ranzato, Marc'Aurelio
Barham, Paul
Computation and Language
Training of large language models (LLMs) is typically distributed across a large number of accelerators to reduce training time. Since internal states and parameter gradients need to be exchanged at each and every single gradient step, all devices need to be co-located using low-latency high-bandwidth communication links to support the required high volume of exchanged bits. Recently, distributed algorithms like DiLoCo have relaxed such co-location constraint: accelerators can be grouped into ``workers'', where synchronizations between workers only occur infrequently. This in turn means that workers can afford being connected by lower bandwidth communication links without affecting learning quality. However, in these methods, communication across workers still requires the same peak bandwidth as before, as the synchronizations require all parameters to be exchanged across all workers. In this paper, we improve DiLoCo in three ways. First, we synchronize only subsets of parameters in sequence, rather than all at once, which greatly reduces peak bandwidth. Second, we allow workers to continue training while synchronizing, which decreases wall clock time. Third, we quantize the data exchanged by workers, which further reduces bandwidth across workers. By properly combining these modifications, we show experimentally that we can distribute training of billion-scale parameters and reach similar quality as before, but reducing required bandwidth by two orders of magnitude.
title Streaming DiLoCo with overlapping communication: Towards a Distributed Free Lunch
topic Computation and Language
url https://arxiv.org/abs/2501.18512