On the Linear Speedup Analysis of Communication Efficient Momentum SGD for Distributed Non-Convex Optimization

TL;DR

This paper proves that a communication-efficient distributed momentum SGD method maintains linear speedup in non-convex optimization, enabling scalable training of deep neural networks with reduced communication overhead.

Contribution

It introduces and analyzes a distributed momentum SGD algorithm that achieves linear speedup and reduced communication complexity in non-convex settings.

Findings

Proves linear speedup property for the proposed method.

Demonstrates reduced communication complexity.

Supports scalable training of deep neural networks.

Abstract

Recent developments on large-scale distributed machine learning applications, e.g., deep neural networks, benefit enormously from the advances in distributed non-convex optimization techniques, e.g., distributed Stochastic Gradient Descent (SGD). A series of recent works study the linear speedup property of distributed SGD variants with reduced communication. The linear speedup property enable us to scale out the computing capability by adding more computing nodes into our system. The reduced communication complexity is desirable since communication overhead is often the performance bottleneck in distributed systems. Recently, momentum methods are more and more widely adopted in training machine learning models and can often converge faster and generalize better. For example, many practitioners use distributed SGD with momentum to train deep neural networks with big data. However, it remains unclear whether any distributed momentum SGD possesses the same linear speedup property as distributed SGD and has reduced communication complexity. This paper fills the gap by considering a distributed communication efficient momentum SGD method and proving its linear speedup property.