Free-threading vs the GIL in mod_wsgi 6.0.0

The previous post in this series walked through tuning WSGISwitchInterval to claw back throughput on a multi-threaded mod_wsgi daemon group whose workload is CPU-bound Python. Tightening the switch interval recovered most of the throughput a two-process, five-thread shape had lost compared with the ten-process, one-thread baseline. What it did not change was per-process CPU usage. Each process…