Performance Profiling Library

When the performance profiling compiler option (-p) is used, the compiler provides each function entry point with a call to a routine, usually known as mcount. For each function, the compiler also sets up a static counter and passes the address of this counter to mcount. The counter is initialized at zero.

The scope of the action performed by mcount is defined by the application. Low-end performance profilers count the number of times the routine is called, and do not do much more than that. The ChorusOS profiler supports an advanced mcount routine within the profiled library (for constructing the runtime call graph).

You can supply your own mcount routine, to assert predicates when debugging a component, for example.