This book constitutes the refereed proceedings of the 15th European Workshop on Computer Performance Engineering, EPEW 2018, held in Paris, France, in October 2018. The 17 papers presented together with the abstracts of two invited talks in this volume were carefully reviewed and selected from 27 submissions. The papers presented at the workshop reflect the diversity of modern performance engineering, with topics ranging from advances in performanceengineering realm, including, dependability and security modeling, performance oriented model verification and testing, hardware and software systems case-studies, applications/extensions of queuing theory and network design

This book constitutes the refereed proceedings of the 17th European Workshop on Computer Performance Engineering, EPEW 2021, and the 26th International Conference, on Analytical and Stochastic Modelling Techniques and Applications, ASMTA 2021, held in December 2021. The conference was held virtually due to COVID 19 pandemic. The 29 papers presented in this volume were carefully reviewed and selected from 39 submissions. The papers presented at the workshop reflect the diversity of modern performance evaluation, with topics ranging from modeling and analysis of network/control protocols and high performance/big data information systems, analysis of scheduling, blockchain technology, analytical modeling and simulation of computer and network systems.