pushViewController Extremely slow

Question

What could cause pushViewController to be extremely slow? (it takes 30+seconds for the new view to appear)

Basically, I'm doing something like this:

SecondViewController *vc = [self.storyboard instantiateViewControllerWithIdentifier:@"correctID"];
vc.something = something;
[self.navigationController pushViewController:vc animated:YES];
CLS_LOG(@"Pushed Controller...");

and i'm logging at the beginning of viewdidload inside the second view controller. I'm not subclassing other methods.

Between Pushed Controller... and the next log from viewdidload there's a huge delay.

How would you debug this?

I already tried with the TimeProfiler but apparently it shows nothing.

Answer 1

Dino's answer saved my life. He got my upvote. I'm just adding this for modern swift users.

     DispatchQueue.main.async {
          self.navigationController?.pushViewController(vc, animated: true)
     }

Answer 2

Had similar problem before, try the following

dispatch_async(dispatch_get_main_queue(), ^{
    // your navigation controller action goes here
});