I tested this with a playbook that installs a set of scripts and dependencies on a server. In all there's ~30 tasks. It takes ~1 minute using CPython 3.10 and ~1.5 minutes using PyPy 3.10 (v7.3.12). Ansible says libyaml is installed in both runtimes so that's ruled out. I wonder if it's the difference in interpreter start-up time, and it accumulates over time as Ansible starts so many Python processes as it runs its tasks.