Dataflow optimization with layer-wise design variables estimation method for enflame CNN accelerators

As convolution layers have been proved to be the most time-consuming operation in convolutional neural network (CNN) algorithms, many efficient CNN accelerators have been designed to boost the performance of convolution operations. Previous works on CNN acceleration usually use fixed design variables for diverse convolutional layers, which would lead to inefficient data movements and low utilization of computing resource. We tackle this issue by proposing a flexible dataflow optimization method with design variables estimation for different layers. The optimization method first narrows the design space by the priori constraints, and then enumerates all legal solutions to select the optimal design variables. We demonstrate the effectiveness of the proposed optimization method by implementing representative CNN models (VGG-16, ResNet-18 and MobileNet V1) on Enflame Technology's programmable CNN accelerator, General Computing Unit (GCU). The results indicate that our optimization can significantly enhance the throughput of the convolution layers in ResNet, VGG and MobileNet on GCU, with improvement of up to 1.84x. Furthermore, it achieves up to 2.08x of GCU utilization specifically for the convolution layers of ResNet on GCU.