As far as My understanding goes it should be 2 threads from 2 different processes and not from the same process because everything could be in a mess.

Think of the situation where both of my thread can run for the same processes then my function need to be re-entrant which means that my same function can be executed at the same time. What probably Intel has told is from marketing point of view where more than one thread can be run but I am yet to be convinced that it can be from the same processes.