Yeah, not to mention that NSMutableArray is not necessarily an array in Objective-C, see: http://ridiculousfish.com/blog/posts/array.html . It really seems like this benchmark is comparing different framework approaches more than any "core language speed" (similar to comparing stl::vector sort of ints in Objective-C++ to NSMutableArray sort of NSNumbers)
Just looking at the "std lib sort", what this might actually be testing off the top of my head is:
1. C-style-array access/write speed of "native arrays" vs. potentially hash-mappy access/write speed of array-like NSMutableArrays.
2. Direct integer comparison (a < b) vs -[NSNumber compare:] method dispatch speed.
3. I don't know how sorted() is implemented internally in Swift, but given that no comparison method is being passed in, you may also be comparing a fast internal int[] sort that directly compares ints to the speed of calling the NSComparisonResult lambda O(n lg n) times.
Just looking at the "std lib sort", what this might actually be testing off the top of my head is:
1. C-style-array access/write speed of "native arrays" vs. potentially hash-mappy access/write speed of array-like NSMutableArrays.
2. Direct integer comparison (a < b) vs -[NSNumber compare:] method dispatch speed.
3. I don't know how sorted() is implemented internally in Swift, but given that no comparison method is being passed in, you may also be comparing a fast internal int[] sort that directly compares ints to the speed of calling the NSComparisonResult lambda O(n lg n) times.