![]() ![]() The Kits make heavy use of these tricks so they are pretty fast. The use of allocation zones can also speed up the VM system a great deal (these aren't as troublesome as IMPs can be, but again aren't as often needed as you might think). They added a method lookup cache which speeds things up a great deal, and IMPs that can be used in tight loops to gain extra zip (healh warning, IMPs are not ususally needed and can cause stunning bugs if you're not careful with them - unless you have a large tight loop that REALLY needs speeding up - don't bother with IMPs). Well sure if you just implemented Objective-C without optimisations then it would be slow, but NeXT (them that did the Objective-C implementation) didn't do that. Macs are based on Objective-C - that's REALLY slow. ![]() Macs have blistering real math performance (the G3 iBook doesn't have the AltiVec). And then there's the amazing AltiVec (which Apple call the "Velocity Engine", if you see these terms they refer to the same thing). The Mac is only 800MHz(ish) for low end machines so it must be slow? This is the classic "MHz Myth" the G4 has a short pipeline (a good thing) and executes over 90% of it's instructions in 1 cycle or less (the modern definition of RISC, TRIVIA: the old definition was implements less the 100 instructions). So the Kernel isn't actually slow, it compares well with other BSDs and Linux. Mac OS X is based on a Microkernel - now everyone agrees these are slow, right? Well, sure I can see where that's coming from - but Apple have gone to great lengths to make this as fast as possible without losing the benefits. Mac OS X isn't actually slow but has a lot of technologies that have got a bad rap (though they didn't always deserve them). ![]()
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