The Proceedings of the 12th Regional School of High-Performance Computing of São Paulo (ERAD-SP 2021) bring the papers selected and presented online, from May 6 to 8, 2021, and organized by the Federal University of ABC (UFABC) and University of São Paulo (USP). In this issue, the proceedings include 16 full papers. These papers were selected through a peer-review, from a total of 16 full papers submitted, which implied an acceptance rate of 100%. The event's program committee was coordinated by Hélio Crestana Guardia and Ricardo Menotti (Federal University of São Carlos), who organized this volume. The articles in this volume were submitted on 03/19/2021, accepted for publication on 04/09/2021, with the final version submitted on 04/18/2021.

You can find more information about ERAD-SP 2021 by visiting the website of the event.