For ~15 years, Python's subprocess.Popen.wait() implemented timeouts using busy-loop polling. This post explains how that was finally replaced with true event-driven waiting on POSIX systems: pidfd_open() + poll() on Linux and kqueue() on BSD / macOS. The result is zero polling and fewer context switches. The same improvement now landing both in psutil and CPython itself.

I have released new psutil 7.2.0, which includes 2 new APIs to inspect C heap memory allocations.

I have also released a new tool called psleak, which detects memory leaks in C extension modules.

https://gmpy.dev/blog/2025/psutil-heap-introspection-apis

https://github.com/giampaolo/psleak/