Swift vs Objective-C: App performance

I am doing some research on Swift and its differences with Objective-C. From what I could gather, the current version of Swift is quite fast, faster even than Objective-C: [see here][1].

However, since most of these tests are done with sorting algorithms and such, I am wondering if Swift will actually be faster than Objective-C when it is used for development of iOS apps. Can anyone enlighten me on this, preferably from their own experience.


[1]:

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Swift comparing to Objective-C has its own benefits like: Swift handles strings more easily, swift tuples offer compound variables, and furthermore, coders don't need to spend time annotating variables with type information and risk making mistakes; in most cases, the compiler can infer the type from the value that a variable is being set with.

Swift is claimed by Apple to be faster than Objective-C, and as you said it is faster in those sorting algorithms, but for the usage of iOS development, a simple user would not recognize the difference between an app developed in Swift or Objective-C. I developed a lot of apps in Objective-C that are in apple store, and now several in Swift and so far users can not tell the difference if one is much faster than the other.

Swift is unlikely to result in applications that run much faster than applications developed in Objective-C. Even though the two languages are quit different, both target the same Cocoa and Cocoa Touch APIs, iOS and OS X a, both are statically typed languages and both use the same LLVM compiler, so they are not that different after all. There will be performance differences, as the two languages aren't identical after all, but don't expect significant differences.

Swift is also developed from Apple to appeal to new programmers because it is similar to languages such as Ruby and Python than it is Objective-C.

Swift is faster compare to Objective-C; that's what Apple's Swift team claims, and it is certainly true. However, the fact is that you have to plan many things in order to write the responsive apps. Here are a few pointers:

1. Remove unused resources
2. Optimize resources for ex images
3. Caching
4. Compression
5. Reusable code
6. Object life management

You can write slow code in any language and Swift is no exception. I haven't had time to fully evaluate the Swift 1.2 Beta but even before most code could be made reasonably fast but it was also very easy to make it very slow. Accessing non-final instance methods especially was very slow and Debug builds were horrifically slow (I have several cases of 100x slower than release builds). A little work to optimise the most deeply nested loops was usually enough to quickly get it somewhere close to C performance.

Most of the code you write is not that performance critical provided you can move slow operations off the main UI queue. More time will be spent in API calls and those will not be affected by the language used to call them. Even where performance is critical the amount of code that needs to be heavily optimised will tend to be small and you could switch to a faster language (e.g. C) for just those parts.

When comparing the Objective-C it is also worth considering what we mean by Objective-C. You can write C functions in Objective-C code and they will result in code as fast as C. I would say that they were C and that to meaningfully talk about Objective-C performance it should be code based on Objective-C message sending and probably NSArrays rather than raw C arrays. If that is the basis Swift (when optimised and using structs and final classes) will come out quite well. However if you are comparing with C code it will usually be the case that Swift will be slower at the moment.

I have a few blog posts about optimising Swift on my [blog](

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) and I gave a [short talk](

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) back in October.

[There is a great blog-post][1] about the improvement of Swift performance especially **after** the Swift 1.2 release.

The author ran several tests with different kind of code like Objc-like Swift code, Swift only and Objective-c only code. And the result was, that Swift 1.2 is much faster than before. He ran tests with JSON so it's a bit more practical than just algorithms.

Beside the 'real' performance, my personal experience about that is, that I'm developing much easier in Swift. I never liked the `.h` and `.m` files from Objective-C because it stopped the 'flow of programming'. Also I think the Syntax itself is much easier than in objective-c [with these brackets].

So I think, if you write a new Project from Scratch, Swift is much easier, faster and more elegant. (My opinion)

[1]:

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