Simple and General Statistical Profiling with PCT

The Profile Collection Toolkit (PCT) provides a novel generalized CPU profiling facility. PCT enables arbitrarily late profiling activation and arbitrarily early report generation. PCT usually requires no re-compilation, re-linking, or even restarting of programs. Profiling reports gracefully degrade with available debugging data. PCT uses its debugger controller, dbctl, to drive a debugger’s control over a process. dbctl has a configuration language that allows users to specify context-specific debugger commands. These commands can sample general program state, such as call stacks and function parameters. For systems or situations with poor debugger support, PCT provides several other portable and flexible collection methods. PCT can track most program code, including code in shared libraries and late-loaded shared objects. On Linux, PCT can seamlessly merge kernel CPU time profiles with user-level CPU profiles to create whole system reports.