Stability

The FBT provider uses DTrace's stability mechanism to describe its stabilities, as shown in the following table. For more information about the stability mechanism, see Chapter 39, Stability.

Element	Name stability	Data stability	Dependency class
Provider	Evolving	Evolving	ISA
Module	Private	Private	Unknown
Function	Private	Private	Unknown
Name	Evolving	Evolving	ISA
Arguments	Private	Private	ISA

As FBT exposes the kernel implementation, nothing about it is Stable — and the Module and Function name and data stability are explicitly Private. The data stability for Provider and Name are Evolving, but all other data stabilities are Private: they are artifacts of the current implementation. The dependency class for FBT is ISA: while FBT is available on all current instruction set architectures, there is no guarantee that FBT will be available on arbitrary future instruction set architectures.