Industrial Case Study on Supporting the Comprehension of System Behaviour under Load

Abstract—Large-scale software systems achieve concurrency on enormous scales using a number of different design patterns. Many of these design patterns are based on pools of pre-existing and reusable threads that facilitate incoming service requests. Thread pools limit thread lifecycle overhead (thread creation and destruction) and resource thrashing (thread proliferation). Despite their potential for scalability, thread pools are hard to configure and test because of concurrency risks like synchro-nization errors and dead lock, and thread pool-specific risks like resource thrashing and thread leakage. Addressing these challenges requires a thorough understanding of the behaviour of the threads in the thread pool. We argue for a methodology to automatically identify and rank deviations in the behaviour of threads based on resource usage. Keywords-thread-pools; behaviour-based clustering; under-standing ULS systems; I