This config is undocumented since #758. The default was changed to "yes" and it is quite useless to set it to "no". Yet, it can happen that some user has an old config file where it is explicitly set to "no". The result will be bad performace, since I/O threads will not do all the I/O.

It's indeed confusing.

1. Either remove the whole option from the code. And thus no need for documentation. OR:
2. Introduce the option back in the configuration, just as a comment is fine. And showing the default value "yes": # io-threads-do-reads yes with additional text.

Originally posted by @melroy89 in #1019 (reply in thread)