What is the overhead associated with std::condition_variable_any

I have read in many places that there is some overhead associated with std::condition_variable_any. Just wondering, what is this overhead?

My guess here is that since this is a generic condition variable that can work with any type of lock, it requires a manually rolled implementation of waiting (perhaps with another condition_variable and mutex or futex, or something similar) so the extra overhead probably comes from that? But not sure... As opposed to just being a native wrapper around pthread_cond_wait() (and equivalent on other systems) etc.

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As a followup, if I was say implementing something that waits on, say, a shared mutex, then is this type of condition variable a bad choice because of the performance overhead? What else can I do in this situation?