The startup time of your app is determined by a bunch of things, but one that you can easily and directly influence, is the time spent in your AppDelegate's function didFinishLaunchingWithOptions. You may have put a number of things in there, and if you want to find out which step is taking up all that time, it's not always useful to fire up Instruments. A simple way is to just dump a bunch of logging statements.
Paste the following code at the top of the AppDelegate.swift file.
var logTimer: CFTimeInterval = -1.0 var logStep = 1
func logAppProgressInit() {
logTimer = CACurrentMediaTime()
} func logAppProgress() {
let stepTime = CACurrentMediaTime() - logTimer
NSLog("Step %d took %.3f seconds", logStep, stepTime)
logStep++
logTimer = CACurrentMediaTime()
}Then paste the following line at the top of your didFinishLaunchingWithOptions:
logAppProgressInit()
And the following line after each (functionally meaningful) line of code in didFinishLaunchingWithOptions:
logAppProgress()
This code is just for a quick round of debugging, and must be removed afterwards. NSLog itself is slow and wasteful in this phase.