Surrogate Model based Co-Optimization of Deep Neural Network Hardware Accelerators

In this paper, we present an ASIC based on 22FDX/FDSOI technology for the detection of atrial fibrillation in human electrocardiograms using neural networks. The ASIC consists of a RISC-V core for supporting software components and an application-specific machine learning IP core (ML-IP), which is used to implement the computationally intensive inference. The ASIC was designed for maximum energy efficiency. A special feature of the ML-IP is its modular, generic and scalable design of the ML-IP which allows to specify the quantization of each computational operation, the degree of parallelization and the architecture of the neural network. This in turn allows the use of ML-based optimization techniques to perform co-optimization for hardware design and architecture of the neural network (NNs). Here, a multi-objective optimization of the overall system is performed with respect to computational efficiency at a given classification accuracy and speed by using a multi-objective optimization, which is carried out using a probabilistic surrogate model. This model tries to find the optimal neural network architecture with a minimum number of training, simulation and evaluation steps.