If you are looking for efficient counters, the counters module was introduced in OTP 21.2. I recently used the counters module to speed up cover.

Thanks for pointing this out. We will update that part of the documentation in OTP 21.3. See Clarify the atomic guarantees for ets:update_counter().

As I recall, the :counters module is built on the :atomic module, which is restricted to only word-sized integers or so, and thus it uses hardware-level atomic instructions (CAS and so forth) to perform efficient updates, where :ets’s is more generically typed, unbounded integers, etc… etc…