Fall-12: Introducing the basics of user-level multithreading

Current parallel libraries and languages often rely on user-level threads to allow for massive concurrency. However, even junior or senior students often have difficulties with the understanding of the pros and cons of user-level threading, due to a lack of concrete experience with its implementation. In this poster, we describe our effort to introduce this concept in the introductory Computer Systems course at PUC-Rio. This is a required course for three of PUC-Rio’s undergraduate programs: Computer Engineering, Computer Science and Information Systems. During the course, students are exposed to basic concepts underlying computer systems, learning and exploring the ways in which these concepts provide support for implementing several abstractions present in typical imperative programming languages. Because the course explores extensively the concepts of execution stack and global data area, it is an ideal point in the curriculum to introduce user-level threads. We describe the theoretical and laboratory material we developed on the topic, in which we explored the concept of coroutines and a basic library that can be built on to implement symmetric and asymmetric coroutines. Keywords-user-level multitasking, coroutines, computer systems