Preemptive Thread and #pragma backgroundTasks

Does #pragma BackgroundTasks False do anything inside a preemptive thread? Since the compiler can’t know ahead of time what kind of thread a given method will run under, I would assume that pragmas do have an effect, and that the code that checks for yields points (e.g. at a loop boundary) would still be there. If so, then #pragma backgroundTasks false should speed things up a little bit?