You don't. As I wrote earlier, we generally very much want to avoid it (as traditionally, it would slow throughput by about 10x - you might want to, again[?], review the Cisco router performance sheet I attached to one of my earlier posts).
However, that's doesn't necessarily mean that the device won't process switch when it must, just that we, effectively, cannot configure process switching for all traffic.
I further recall (?), Cisco's reason why you could not disable CEF (if in fact you cannot), was because CEF is now so integral to many other Cisco features. (Personally, this somewhat reminds me of, years ago, with a new release of Windows, Microsoft stated it could not run without Internet Explorer. [BTW, I'm not implying either Microsoft or Cisco are "fibbing", just that for many different reasons, they didn't see good reasons to do otherwise. Again, for Cisco, generally everyone wants to avoid process switching, so why still allow a device to only use it?])
