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SPECIAL ISSUE: ARTIFICIAL INTELLIGENCE AND MACHINE LEARNING TECHNOLOGIES
Activations and gradients compression for model-parallel training
M. I. Rudakovab, A. N. Beznosikovab, Y. A. Kholodovab, A. V. Gasnikovab a Innopolis University, Innopolis, Republic of Tatarstan
b Moscow Institute of Physics and Technology, Moscow, Russia
Abstract:
Large neural networks require enormous computational clusters of machines. Model-parallel training, when the model architecture is partitioned sequentially between workers, is a popular approach for training modern models. Information compression can be applied to decrease workers' communication time, as it is often a bottleneck in such systems. This work explores how simultaneous compression of activations and gradients in model-parallel distributed training setup affects convergence. We analyze compression methods such as quantization and TopK compression, and also experiment with error compensation techniques. Moreover, we employ TopK with AQ-SGD per-batch error feedback approach. We conduct experiments on image classification and language model fine-tuning tasks. Our findings demonstrate that gradients require milder compression rates than activations. We observe that $K=10\%$ is the highest TopK compression level, which does not harm model convergence severely. Experiments also show that models trained with TopK perform well only when compression is also applied during inference. We find that error feedback techniques do not improve model-parallel training compared to plain compression, but allow model inference without compression with almost no quality drop. Finally, when applied with the AQ-SGD approach, TopK stronger than with $K=30\%$ worsens model performance significantly.
Keywords:
distributed learning, model parallelism, activation compression, gradient compression.
Citation:
M. I. Rudakov, A. N. Beznosikov, Y. A. Kholodov, A. V. Gasnikov, “Activations and gradients compression for model-parallel training”, Dokl. RAN. Math. Inf. Proc. Upr., 514:2 (2023), 126–137; Dokl. Math., 108:suppl. 2 (2023), S272–S281
Linking options:
https://www.mathnet.ru/eng/danma458 https://www.mathnet.ru/eng/danma/v514/i2/p126
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Abstract page: | 106 | References: | 13 |
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