Refactoring-based learning for fine-grained lock in concurrent programming course

Fine-grained lock is frequently used to mitigate lock contention in the multithreaded program running on a shared-memory multicore processor. However, a concurrent program based on the fine-grained lock is hard to write, especially for beginners in the concurrent programming course. How to help participants learn fine-grained lock has become increasingly important and urgent. To this end, this paper presents a novel refactoring-based approach to enhance the learning effectiveness of fine-grained locks. Two refactoring tools are introduced to provide illustrating examples for participants by converting original coarse-grained locks into fine-grained ones automatically. Learning effectiveness and limitations are discussed when refactoring tools are applied. We evaluate students' outcomes with two benchmarks and compare their performance in Fall 2018 with those in Fall 2019. We also conduct experiments on students' outcomes by dividing them into two groups (A and B) in a controlled classroom where participants in group A learn the fine-grained locks with the help of refactoring tools while those in group B do not access these tools. Evaluation of the results when they have been taught with the refactoring-based approach reveals a significant improvement in the students' learning.