TSGL: A tool for visualizing multithreaded behavior

Since multicore processors are now the architectural standard and parallel computing is in the core CS curriculum, CS educators must create pedagogical materials and tools to help their students master parallel abstractions and concepts. This paper describes the thread safe graphics library (TSGL), a tool by which an educator can add graphics calls to a working multithreaded program in order to make visible the underlying parallel behavior. Using TSGL, an instructor (or student) can create parallel visualizations that clearly show the parallel patterns or techniques a given program is using, allowing students to see the parallel behavior in near real-time as the program is running. TSGL includes many examples that illustrate its use; this paper presents a representative sample, that can be used either in a lecture or a self-paced lab format. We also present evidence that such visualizations improve student understanding of abstract parallel concepts.