  Federated learning (FL) promotes decentralized training while prioritizing
data confidentiality. However, its application on resource-constrained devices
is challenging due to the high demand for computation and memory resources to
train deep learning models. Neural network pruning techniques, such as dynamic
pruning, could enhance model efficiency, but directly adopting them in FL still
poses substantial challenges, including post-pruning performance degradation,
high activation memory usage, etc. To address these challenges, we propose
FedMef, a novel and memory-efficient federated dynamic pruning framework.
FedMef comprises two key components. First, we introduce the budget-aware
extrusion that maintains pruning efficiency while preserving post-pruning
performance by salvaging crucial information from parameters marked for pruning
within a given budget. Second, we propose scaled activation pruning to
effectively reduce activation memory footprints, which is particularly
beneficial for deploying FL to memory-limited devices. Extensive experiments
demonstrate the effectiveness of our proposed FedMef. In particular, it
achieves a significant reduction of 28.5% in memory footprint compared to
state-of-the-art methods while obtaining superior accuracy.
