This book constitutes the proceedings of the 31st International Conference on Architecture of Computing Systems, ARCS 2018, held in Braunschweig, Germany, in April 2018. The 23 full papers presented in this volume were carefully reviewed and selected from 53 submissions. ARCS has always been a conference attracting leading-edge research outcomes in Computer Architecture and Operating Systems, including a wide spectrum of topics ranging from embedded and real-time systems all the way to large-scale and parallel systems.