CaBaFL: Asynchronous Federated Learning via Hierarchical Cache and Feature Balance

TL;DR

CaBaFL introduces an asynchronous federated learning framework with hierarchical caching and feature balance strategies, significantly improving training speed and accuracy in AIoT applications by addressing stragglers and data imbalance.

Contribution

It proposes a novel asynchronous FL approach with hierarchical cache aggregation and feature balance-guided device selection, enhancing efficiency and model performance.

Findings

Achieves up to 9.26X training acceleration.

Improves accuracy by up to 19.71%.

Effectively mitigates stragglers and data imbalance.

Abstract

Federated Learning (FL) as a promising distributed machine learning paradigm has been widely adopted in Artificial Intelligence of Things (AIoT) applications. However, the efficiency and inference capability of FL is seriously limited due to the presence of stragglers and data imbalance across massive AIoT devices, respectively. To address the above challenges, we present a novel asynchronous FL approach named CaBaFL, which includes a hierarchical Cache-based aggregation mechanism and a feature Balance-guided device selection strategy. CaBaFL maintains multiple intermediate models simultaneously for local training. The hierarchical cache-based aggregation mechanism enables each intermediate model to be trained on multiple devices to align the training time and mitigate the straggler issue. In specific, each intermediate model is stored in a low-level cache for local training and when it is trained by sufficient local devices, it will be stored in a high-level cache for aggregation. To address the problem of imbalanced data, the feature balance-guided device selection strategy in CaBaFL adopts the activation distribution as a metric, which enables each intermediate model to be trained across devices with totally balanced data distributions before aggregation. Experimental results show that compared with the state-of-the-art FL methods, CaBaFL achieves up to 9.26X training acceleration and 19.71\% accuracy improvements.