Understanding, Refactoring, and Fixing Concurrency in C#

Industry leaders provide concurrent libraries because asynchronous & parallel programming are increasingly in demand: responsiveness, scalability, and high-throughput are key elements of all modern applications. However, we know little about how developers use these concurrent libraries in practice and the developer´s toolbox for concurrency is very limited. We present the first study that analyzes the usage of concurrent libraries in large codebases, such as 2258 open-source C# apps comprising 54M SLOC and 1378 open-source Windows Phone apps comprising 12M SLOC. Using this data, we find important problems about use and misuse of concurrency. Inspired by our findings, we designed, evaluated, and implemented several static analyses and refactoring tools.