--thunder-lock is available since uWSGI 1.4.6 but never got documentation (of any kind)
Serializing accept(), AKA Thundering Herd, AKA the Zeeg Problem — uWSGI 2.0 documentation
https://uwsgi-docs.readthedocs.io/en/latest/articles/SerializingAccept.html#uwsgi-docs-sucks-thunder-lock
why --thunder-lock is not the default when multiprocess + multithread is requested.