I have been fighting with a weird issue for some time now, perhaps you can point me in the right direction!
So, using Cocos2d for Mac, I experience weird stuttering even when there is no load to speak of, in fact I could also reproduce it in a newly created Cocos2d project. The SPF statistic seems to 'accumulate' time, up to 0.016 (which, of course, is 1/60) and then revert to 0, at which point the game will stutter for (probably) one frame.
With a dirty trick, namely just returning 1/60 in the -[CCDirectorDisplayLink calculateDeltaTime] method, everything works much more smoothly, but not really perfect yet. I don't like this solution because I don't know what kind of weird timing issue I am going to run into, I can already guess that it's going to be a bitch to debug. :-)
So, what can I do to make my game run smoothly?
I am currently developing an action shooter kind of game, so this would be really annoying for the players.
Edit: the initial Cocos2d project for iOS doesn't have this problem, the spf stays at around a nice 0.003 seconds. So, is this an issue with the CCDirector for Mac OS? I also read that the DisplayLink on Mac OS is not at all comparable to the one for iOS and not the ideal solution to get your timer ticks ...