Does coding many small methods have performance ramifications for Objective-C?

Question

I come from Ruby, and have sort of adopted the methodology of single responsibility principle, encapsulation, loose coupling, small testable methods, etc., so my code tends to jump from method to method frequently. That's the way I am used to working in the Ruby world. I argue that this is the best way to work, mainly for BDD, as once you start having "large" methods that do multiple things, it becomes very difficult to test.

I am wondering if there are any draw backs to this approach as far as noticeable differences in performance?

Answer 1

Yes, there will always be some amount of performance impact unless you have a compiler that inlines things, but if you do dynamic method lookup (like Ruby and Obj-C), you can't inline, and so there will be some impact. However, it really depends on the language and the calling conventions. If you have a call in Objective-C, you know that the overhead will be the overhead of of using the C calling conventions once (calling objc_msg_send), then a method lookup, and then some sort of jump (most likely also C calling conventions, but could be anything). You have to remember, though, that unless you're writing C and assembly, it's almost impossible to see any difference.