critical real-time things should be done differently... by reading you.
I mean: if you need a kind of "done" message, it probably means cpu has a lot of things to do. So, in order to have this "done" message, you want to build another "system" that handles the completeness of processes to inform you with "done" messages...
so cpu would have more work to do...
it doesn't make sense for me :P
I'd choose another way...