Library Function Tracking with XALT.

XALT is a tracking tool that collects accurate, detailed, and continuous job-level and link-time data. XALT stores that data in a database and ensures that all the data collection is transparent to the users. XALT tracks libraries and object files linked by the application. A recent feature improvement in XALT enable it to also track external subroutines and functions called by an application. This paper describes the function-tracking implementation in XALT and showcases the kind of data and analysis that becomes available from this new feature. A recently developed web-based interface to XALT database is also described, allowing the staffs of a supercomputing center to more easily understand software usage on their compute resources.