Pearl: Towards Optimization of DNN-accelerators Via Closed-Form Analytical Representation

Hardware accelerators for deep learning are proliferating, owing to their high-speed and energy-efficient execution of deep neural network (DNN) workloads. Ensuring an efficient DNN accelerator design requires a vast design-space exploration of a large number of parameters. However, current exploration frameworks are limited by slow architectural simulations, which limit the number of design points to be examined. To address this challenge, in this paper we introduce Pearl, an analytical representation of executing the DNN inference, mapped to an accelerator. Pearl provides immediate estimates of performance and energy of DNN accelerators, where we incorporate new parameters to capture dataflow mapping schemes beneficial for DNN systems. We model equations that represent utilization rates of the compute fabric for different dataflow mappings. We validate the accuracy of our equations against a state-of-the-art cycle-accurate DNN hardware simulator. Results show that Pearl achieves $< 1.0\%$ and $< 1.3\%$ average error in performance and energy estimates, respectively, while achieving $> 1.2\cdot 10^{7}\times$ simulation speedup. Pearl shows higher average accuracy than existing analytical models that support the simulator. We also leverage Pearl to explore and optimize area-constrained DNN accelerators targeting inference on full HD resolution.