- Artificially disabled APC.
- Reloaded the page, saw all the setup stuff run.
- Reloaded the page, saw no setup stuff run (i.e., cache was hit).
- Restarted the webserver.
- Reloaded the page, saw all the setup stuff run.
- Reloaded again, got a cache hit.
I don't really know how to reproduce the exact problem with the parent PID not working, but from T9599 it sounds like this fixed the issue and from my test plan we still appear to get correct behavior in the standard/common case.