https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106772
--- Comment #20 from Mkkt Bkkt <valera.mironow at gmail dot com> --- My main concern with this optimization it's not zero-overhead. It's not necessary when we expect we have some waiters, in that case it just additional synchronization and contention in waiter pool (that have small fixed size, just imagine system with 100+ cores, if we have > 16 waiting threads some of them make fetch_add/sub on the same atomic, that can be expensive, especially on numa) And at the same time, I don't understand when I need to notify and cannot know notification not needed. I don't understand when it useful.
