[thdc]

I actually came across the 400ms number in a 2019 WWDC talk while researching the topic! It said 100ms of that time was delegated to the iOS system for setup, leaving 300ms for whatever your app does.

Granted the 100ms section included System Interface - DYLD3 (dynamic linking) as part of it, which includes the 200ms portion that was optimized in tfa so I don't know how accurate that 100-300 breakup is.

The talk also says to avoid dynamic library loading during launch to improve time which is interesting, as it suggests there's an alternative, which may or may not be what Doordash did here.

[saagarjha]

Using dlopen is generally not a performant option unless you are doing it off the startup path.