4 ms·

Objective-C uses ref counting and does alright... Hardly a language that doesn't prioritize performance.

by dilap 13y ago

comex 13y ago
Objective-C, a language which uses dynamic dispatch for all method calls and does not do any kind of type-specialized code generation, certainly does not prioritize performance.
- millstone 13y ago
  It priorities performance in one important respect: by providing direct access to C. It's common in many languages to write performance critical sections in C or even assembly. This is trivial in ObjC, which has C as a subset, so it is done more often than in e.g. Python or Java. Interoperability with FFIs is one of the advantages of reference counting over GC. You don't have to worry about pinning allocations, allocation coloring, unscanned roots, etc. The ObjC refcounting operations (CFRetain/CFRelease), and the collection types (CFArray, CFString, CFSet...) are all trivially available from C as well. I speculate that this better interoperability with C is why Apple deprecated GC and went with ARC. We can see Microsoft sort of moving in the same direction with WinRT.
- dilap 13y ago
  I guess the phrase "prioritize performance" is maybe ambiguous. It's a language that cares a lot about performance, let's say -- sure, it uses dynamic dispatch for its method calls (losing a little speed compared more-static C++ virtual methods, which themselves lose a little speed compared to non-virtual methods), but the implementation itself is very optimized (there's some good blog articles describing the implementation, but I don't have them at hand), and you always have normal function calls as in C if you need maximum speed (as millstone mentioned). C really feels like a first-class language when using Objective-C, and C is a pretty damn fast language. (As an aside, there was an optional GCed variant of objective-c around for a while. Not sure what the performance impact was vs ref counted.)

Objective-C uses ref counting and does alright... Hardly a language that doesn't prioritize performance.

by dilap 13y ago

Objective-C uses ref counting and does alright... Hardly a language that doesn't prioritize performance.

comex 13y ago

Objective-C, a language which uses dynamic dispatch for all method calls and does not do any kind of type-specialized code generation, certainly does not prioritize performance.

millstone 13y ago
It priorities performance in one important respect: by providing direct access to C. It's common in many languages to write performance critical sections in C or even assembly. This is trivial in ObjC, which has C as a subset, so it is done more often than in e.g. Python or Java. Interoperability with FFIs is one of the advantages of reference counting over GC. You don't have to worry about pinning allocations, allocation coloring, unscanned roots, etc. The ObjC refcounting operations (CFRetain/CFRelease), and the collection types (CFArray, CFString, CFSet...) are all trivially available from C as well. I speculate that this better interoperability with C is why Apple deprecated GC and went with ARC. We can see Microsoft sort of moving in the same direction with WinRT.
dilap 13y ago
I guess the phrase "prioritize performance" is maybe ambiguous. It's a language that cares a lot about performance, let's say -- sure, it uses dynamic dispatch for its method calls (losing a little speed compared more-static C++ virtual methods, which themselves lose a little speed compared to non-virtual methods), but the implementation itself is very optimized (there's some good blog articles describing the implementation, but I don't have them at hand), and you always have normal function calls as in C if you need maximum speed (as millstone mentioned). C really feels like a first-class language when using Objective-C, and C is a pretty damn fast language. (As an aside, there was an optional GCed variant of objective-c around for a while. Not sure what the performance impact was vs ref counted.)