Efficient Extreme Large-Scale Speaker Verification: Dynamic Active Sub Fully-Connected Layers for Faster Training and Memory Optimization

Using larger scale datasets in the training stage of speaker verification model usually leads to better performance. However, when the speaker number of the training dataset becomes extreme large (e.g., more than 1 million), the training speed and GPU memory demand will become bottlenecks which are mainly brought by the extreme large dimension of last fully-connected(FC) layer’s weight matrix. We propose dynamic active sub FC layers (DAS-FC) to tackle this problem. Firstly, all speakers are dynamically divided into speaker groups by clustering rows of last FC layer’s weight matrix. Then, sub FC layers are generated according to speaker groups for model training. We also introduce Mini-Batch K-means and speaker based dataloader to further reduce time and resource costing. Experiments on an extreme large dataset with 1,068,237 speakers show that compared to traditional FC layer, DAS-FC can save up to 87% training time and save 56% GPU memory occupancy with only a 4.2% drop in model performance.