Lockless algorithms for mere mortals

If the reference counter is incremented relaxed, (for common use cases) it implies that read/write access is synchronized separately. So I'd expect that decrementing can be relaxed as well if the thread that encounters a zero reference count still has read/write access (otherwise it should be enough to use a simple load-acquire on the synchronization variable).

However the (separate) synchronization of read/write access, which can't be relaxed, probably makes the gain look small in comparison, even on those platforms where it is larger. Which makes me wonder how large it is.