Oprofile is a performance monitoring tool for Linux that allows developers to analyze the behavior of their applications and systems. It collects data on CPU usage, memory usage, and other performance metrics, and users can analyze the data to identify bottlenecks and optimize their code. Oprofile is commonly used for profiling and optimizing server applications, embedded systems, and other high-performance computing applications. A specialized skill in Oprofile would involve proficiency in using the tool to gather and analyze performance data, as well as an understanding of system architecture and optimization techniques.