Sun 17 - Fri 22 October 2021 Chicago, Illinois, United States
Sun 17 Oct 2021 14:40 - 15:05 at Zurich F - Safety and Failures Chair(s): Joeri De Koster

Programs written using Communicating Event-Loops (CEL) concurrency model do not suffer from low-level data races by design but are not exempt from other concurrency bugs, such as behavioral deadlocks and message order violations.

When programmers need to find the root cause of a bug, they typically ask questions about the application's behavior.
However, current debugging tools are mostly operational, offering features at the source code level like breakpoints and watchpoints.
Consequently, understanding the program behavior when debugging can take a lot of time for developers since questions on behaviors need to be mapped into operations in the debugger.

Inspired by interrogative debugging, this paper proposes an interactive debugging approach for actor-based programs that enable developers to reason about the program output by selecting questions from a set of predefined questions about the code and the program's execution.
We present the design of the questions and answers, and we describe a prototype implementation in Apgar, an online debugger for actor-based programs written in SOMns.
We define questions based on key concepts of the actor model: actors, turns, messages, and promises.
The debugger then computes the answers by analyzing a recorded trace of events about the program execution.

Slides (Slides.pdf)5.76MiB

Sun 17 Oct

Displayed time zone: Central Time (US & Canada) change

13:50 - 15:10
Safety and FailuresAGERE at Zurich F
Chair(s): Joeri De Koster Vrije Universiteit Brussel, Belgium
Contract-Based Return-Value Commutativity: Safely Exploiting Contract-Based Commutativity for Faster Serializable Transactions
Tim Soethout ING Bank; CWI, Tijs van der Storm CWI; University of Groningen, Jurgen Vinju CWI; Eindhoven University of Technology
DOI Pre-print File Attached
A model of actors and grey failures
Laura Bocchi University of Kent, Julien Lange Royal Holloway University of London, Simon Thompson IOHK, University of Kent, and ELTE, A. Laura Voinea University of Kent, UK
What’s the Problem? Interrogating Actors to Identify the Root Cause of Concurrency Bugs
Carmen Torres Lopez Vrije Universiteit Brussel, Louise Van Verre Vrije Universiteit Brussel, Elisa Gonzalez Boix Vrije Universiteit Brussel
DOI Pre-print File Attached
Day closing
Elias Castegren Uppsala University, Sweden, Simon Fowler University of Glasgow, Joeri De Koster Vrije Universiteit Brussel, Belgium