iOS and macOS™ Performance Tuning: Cocoa®, Cocoa Touch®, Objective-C®, and Swift™

3. CPU: Pitfalls and Techniques

Having had a look at the parameters driving performance and techniques for identifying slow code, let’s now turn to actual techniques for making code run fast. We will look at efficient object representations and ways for those objects to communicate and access data. We will also examine streamlining computation. In all this, the objective will typically be to effectively combine the “Objective” and the “C” parts of Objective-C to achieve the desired balance between performance and encapsulation.

In general, the basic idea is for objects to have C on the inside and messages on the outside, and for the objects themselves to be fairly coarse-grained, mostly static entities. When following these principles, it is ...