Chimera: Efficiently Training Large-Scale Neural Networks with Bidirectional Pipelines

Fuente: arXiv
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Autori principali: Li, Shigang, Hoefler, Torsten
Natura: Preprint
Pubblicazione: 2021
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author Li, Shigang
Hoefler, Torsten
author_facet Li, Shigang
Hoefler, Torsten
contents Training large deep learning models at scale is very challenging. This paper proposes Chimera, a novel pipeline parallelism scheme which combines bidirectional pipelines for efficiently training large-scale models. Chimera is a synchronous approach and therefore no loss of accuracy, which is more convergence-friendly than asynchronous approaches. Compared with the latest synchronous pipeline approach, Chimera reduces the number of bubbles by up to 50%; benefiting from the sophisticated scheduling of bidirectional pipelines, Chimera has a more balanced activation memory consumption. Evaluations are conducted on Transformer based language models. For a GPT-2 model with 1.3 billion parameters running on 2,048 GPU nodes of the Piz Daint supercomputer, Chimera improves the training throughput by 1.16x-2.34x over the state-of-the-art synchronous and asynchronous pipeline approaches.
format Preprint
id arxiv_https___arxiv_org_abs_2107_06925
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Chimera: Efficiently Training Large-Scale Neural Networks with Bidirectional Pipelines
Li, Shigang
Hoefler, Torsten
Distributed, Parallel, and Cluster Computing
Machine Learning
C.1.4; I.2.11
Training large deep learning models at scale is very challenging. This paper proposes Chimera, a novel pipeline parallelism scheme which combines bidirectional pipelines for efficiently training large-scale models. Chimera is a synchronous approach and therefore no loss of accuracy, which is more convergence-friendly than asynchronous approaches. Compared with the latest synchronous pipeline approach, Chimera reduces the number of bubbles by up to 50%; benefiting from the sophisticated scheduling of bidirectional pipelines, Chimera has a more balanced activation memory consumption. Evaluations are conducted on Transformer based language models. For a GPT-2 model with 1.3 billion parameters running on 2,048 GPU nodes of the Piz Daint supercomputer, Chimera improves the training throughput by 1.16x-2.34x over the state-of-the-art synchronous and asynchronous pipeline approaches.
title Chimera: Efficiently Training Large-Scale Neural Networks with Bidirectional Pipelines
topic Distributed, Parallel, and Cluster Computing
Machine Learning
C.1.4; I.2.11
url https://arxiv.org/abs/2107.06925