When Relocations are Performed

All data reference relocations must be carried out during process initialization before the application gains control, whereas any function reference relocations can be deferred until the first instance of a function being called. By reducing the number of data relocations, the runtime initialization of a process will be reduced.

Initialization relocation costs can also be deferred by converting data relocations into function relocations, for example, by returning data items by a functional interface. This conversion usually results in a perceived performance improvement as the initialization relocation costs are effectively spread throughout the process's lifetime. It is also possible that some of the functional interfaces will never be called by a particular invocation of a process, thus removing their relocation overhead altogether.

The advantage of using a functional interface can be seen in the section, "Copy Relocations". This section examines a special, and somewhat expensive, relocation mechanism employed between dynamic executables and shared objects, and provides an example of how this relocation overhead can be avoided.