Programmers compile their instrumented source code and link it with the trace library.
During program execution, perfomance data captured by the instrumentation is recorded in SDDF files. Termination routines , placed just after instrumentation, return control to the application making the call. When an instrumented event occurs, the trace library generates a record of the occurrence, a trace record, written in SDDF format. Each SDDF file contains both record descriptors and data records. The record descriptors define the structure of data records to be generated for each occurence of targeted events, enabling ready interpretation of trace data records by analysis tools.