A “Performance Evaluator” provides various techniques for tracking system events to diagnose root causes of application performance anomalies. In general, traces of system events involved in inter-thread interactions are collected at application runtime. These traces are then used to construct inter-thread dependency patterns termed “control patterns.” Control patterns are then evaluated to determine root causes of performance anomalies. Where an application terminates abnormally or full traces cannot be collected for some reason, partial control patterns are constructed for that application. In various embodiments, “fingerprints” are then generated from full or partial control patterns and are matched to fingerprints corresponding to operations in other control patterns extracted from reference traces collected on the same or similar systems. Matched fingerprints or control patterns are then used to deduce the root cause of application performance anomalies associated with full or partial traces.