Function Boundary Probes
The pid provider enables you to trace function entry and return in user
programs just as the FBT provider provides that capability for the kernel.
Most of the examples in this manual that use the FBT provider to
trace kernel function calls can be modified slightly to apply to user processes.
entry Probes
An entry probe fires when the traced function is invoked. The arguments to
entry probes are the values of the arguments to the traced function.
return Probes
A return probes fires when the traced function returns or makes a tail
call to another function. The value for arg0 is the offset in the
function of the return instruction; arg1 holds the return value.
Note - Using argN returns the raw unfiltered values as type int64_t. The pid provider does
not support the args[N] format.
