Editorial

The ACM Proceedings of the ACM on Measurement and Analysis of Computing Systems (POMACS) focuses on the measurement and performance evaluation of computer systems and operates in close collaboration with the ACM Special Interest Group SIGMETRICS. All papers in the last three (i.e., this one and the previous two) issues of POMACS will be presented during the ACM SIGMETRICS 2021 virtual conference. Each of the three issues (one per call for papers) contains papers selected by the editorial board via a rigorous review process that follows a hybrid conference and journal model, with reviews conducted by the 86 members of our POMACS editorial board. Each paper was either conditionally accepted (and shepherded), allowed a "one-shot" revision (to be resubmitted to one of the subsequent two deadlines), or rejected (with resubmission allowed after a year). Over the three issues during which we have served as editors, POMACS has published 35 papers out of 315 submissions (84 to the Summer call, 107 to the Fall call, and 124 to the Winter call). All submitted papers received at least 3 reviews and we held an online TPC meeting for each deadline/issue. Based on the indicated primary track, roughly 16% of the submissions were in the Learning track, 29% were in the Measurement & Applied Modeling track, 26% were in the Systems track, and 29% were in the Theory track. Many people contributed to the success of POMACS over the last year. First, we would like to thank the authors, who submitted their best work to SIGMETRICS/POMACS. Second, we would like to thank the TPC members who provided constructive feedback in their reviews to authors and participated in the online discussions and TPC meetings. We also thank the several external reviewers who provided their expert opinion on specific submissions that required additional input. We are also grateful to the SIGMETRICS Board Chair, Giuliano Casale, and to past TPC Chairs, Athina Markopoulou and Y. C. Tay, who provided a wealth of information and guidance. We also thank Adam Wierman for outlining the soft tracking guidelines that were adopted for SIGMETRICS 2021. Finally, we are grateful to the Organization Committee and to the SIGMETRICS Board for their efforts and initiatives in the middle of a pandemic, including making papers and videos available online and enabling online interactions.