Floorplan is an important process whose quality determines the timing closure in integrated circuit (IC) physical design. And generating a floorplan with satisfying timing result is time-consuming because much time is spent on the generation-evaluation iteration. Applying machine learning to the floorplan stage is a potential method to accelerate the floorplan iteration. However, there exist two challenges which are selecting proper features and achieving a satisfying model accuracy. In this paper, we propose a machine learning framework for floorplan acceleration with feature selection and model stacking to cope with the challenges, targeting to reduce time and effort in integrated circuit physical design. Specifically, the proposed framework supports predicting post-route slack of static random-access memory (SRAM) in the early floorplan stage. Firstly, we introduce a feature selection method to rank and select important features. Considering both feature importance and model accuracy, we reduce the number of features from 27 to 15 (44% reduction), which can simplify the dataset and help educate novice designers. Then, we build a stacking model by combining different kinds of models to improve accuracy. In 28 nm technology, we achieve the mean absolute error of slacks less than 23.03 ps and effectively accelerate the floorplan process by reducing evaluation time from 8 hours to less than 60 seconds. Based on our proposed framework, we can do design space exploration for thousands of locations of SRAM instances in few seconds, much more quickly than the traditional approach. In practical application, we improve the slacks of SRAMs more than 75.5 ps (177% improvement) on average than the initial design.

Neuromorphic computing is considered to be the future of machine learning, and it provides a new way of cognitive computing. Inspired by the excellent performance of spiking neural networks (SNNs) on the fields of low-power consumption and parallel computing, many groups tried to simulate the SNN with the hardware platform. However, the efficiency of training SNNs with neuromorphic algorithms is not ideal enough. Facing this, Michael et al. proposed a method which can solve the problem with the help of DNN (deep neural network). With this method, we can easily convert a well-trained DNN into an SCNN (spiking convolutional neural network). So far, there is a little of work focusing on the hardware accelerating of SCNN. The motivation of this paper is to design an SNN processor to accelerate SNN inference for SNNs obtained by this DNN-to-SNN method. We propose SIES (Spiking Neural Network Inference Engine for SCNN Accelerating). It uses a systolic array to accomplish the task of membrane potential increments computation. It integrates an optional hardware module of max-pooling to reduce additional data moving between the host and the SIES. We also design a hardware data setup mechanism for the convolutional layer on the SIES with which we can minimize the time of input spikes preparing. We implement the SIES on FPGA XCVU440. The number of neurons it supports is up to 4000 while the synapses are 256000. The SIES can run with the working frequency of 200 MHz, and its peak performance is 1.5625 TOPS.