This book constitutes the refereed proceedings papers from the 8th International Workshop on Performance Modeling, Benchmarking and Simulation of High Performance Computing Systems, PMBS 2017, held in Denver, Colorado, USA, in November 2017. The 10 full papers and 3 short papers included in this volume were carefully reviewed and selected from 36 submissions. They were organized in topical sections named: performance evaluation and analysis; performance modeling and simulation; and short papers.