Nib files loading extremly slow

Question

Good day friends!

I have very strange performance results on loading Nib files. Here is a screen from TimeProfiler:

Overall it sometimes takes more than 1200 ms to load a simple viewController that has 2 nibs. Nibs are very simple. Here is an example. As you can see from screenshot above, it takes 311 ms to be loaded:

The code I use to load nibs:

required init(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    setupXib()
}

func setupXib() {
    NSBundle.mainBundle().loadNibNamed("TimeSaver", owner: self, options: nil)
    bounds = view.bounds
    addSubview(view)
    setup()
}

func setup() {
    slider.maximumValue = 30.0
    slider.minimumValue = 1.0
    slider.value = 5.0
    timeLabel.text = "\(sliderValue.format(format)) min"
}

I don't know if it might cause a problem, but this app uses App Groups (for WatchExtension). As you see I call nibs from mainBundle as they all are in main target. May it be the reason?

Thank you!

Answer 1

So the problem was not in nib files at all. It was about custom font that was not installed properly. It was in list in Storyboard, but it was not a member of correct target. So the app was looking through everywhere to find a damn font - and that was the performance issue.