After trying to figure out why converting all our text fields to TLF is hammering performance for ages, I've finally discovered the culprit function that is taking so long on every single frame:
RuntimeManager$.checkTLFFontsLoaded (fl.text)
This function often spends more than 10 ms running each frame, and is by far the longest running function in our application's action script every single frame.
Can anyone give me a rough idea of what calls this function so I know what to start looking for in my code?