Explore a 15-minute conference talk from USENIX NSDI '22 that introduces Collie, a tool designed to uncover performance anomalies in RDMA subsystems. Learn how Collie constructs a comprehensive search space for application workloads and uses simulated annealing to drive RDMA-related performance and diagnostic counters to extreme value regions. Discover the tool's effectiveness in finding 15 new performance anomalies across various RDMA NIC, CPU, and hardware component combinations. Gain insights into the challenges of defining performance anomalies, creating a comprehensive search space, and implementing efficient search algorithms. Understand the importance of hardware counters as search signals and the concept of Minimal Feature Set (MFS) in Collie's approach. Examine the evaluation settings, lessons learned, and future work directions for improving RDMA subsystem performance testing.