- Enable the kernel to trace a function at its return.
- It's first purpose is to trace the duration of functions.
- This is done by setting the current return address on the thread
- info structure of the current task.
+ Enable the kernel to trace a function at both its return
+ and its entry.
+ It's first purpose is to trace the duration of functions and
+ draw a call graph for each thread with some informations like
+ the return value.
+ This is done by setting the current return address on the current
+ task structure into a stack of calls.