correct. (except that docs i have suggest this was introduced in the ppro)
> > o makes the contention case use 'conventional' calling style.
>
> Perhaps this change only makes sense if the out-of-line case ever
> returns without scheduling. I'm not sure if it does (but I can think of
> a few tricks where that would be useful). If it always schedules the
> RSB mispredication overhead is still there and you've added a bit more
> overhead. Though for some cases of semaphore contention I guess the RSB
> could be right despite scheduling.
hmm, interesting thoughts. I can't at the moment think of a way to
time the difference; i strongly suspect that the old way was not
better - mispredicted branches caused by an out of sync rsb would
probably outweight any benefits that one removed unconditional jump
could give. These funtions _can_ return without scheduling.
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