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It seems like Apple would be a pretty good candidate for the "Heterogeneous System Architecture" work AMD has been doing, x86_64 and ARM on the same SOC. Leave
by trotsky 14y ago
It seems like Apple would be a pretty good candidate for the "Heterogeneous System Architecture" work AMD has been doing, x86_64 and ARM on the same SOC. Leave the x86 cores off when you don't need them.
- twoodfin 14y agoIf anyone has both the technical know how to come up with a "good enough" development scheme to make that work, and the leverage with their developers to ensure support, it's Apple. But yikes that sounds like a hard problem. How do you migrate a process from one ISA to the other? Some kind of compiler-enforced "safe points" where there's a sensible mapping of the IP and other instruction stream-sensitive state?
- geon 14y agoLots of systems have been buils with multiple processor architectures, including the early Macs, the Nintendo DS, the PS3, and every PC the last decade (cpu+gpu). You would usually write your code to use one specific cpu, rather than trying to balance the load automatically like on a heterogenous system.
- twoodfin 14y agoI thought trotsky was suggesting an ARM/x86 mix along the lines of ARM's big.LITTLE, which allows process migration between two very differently implemented (though ISA-compatible) cores.
- trotsky 14y agoWhile they haven't announced any of it in public, it does seem hard to believe they'd be migrating running applications. It's much more likely that they're targeting nx page sharing, you'd still have build the os for both isas, but it'd allow you to run many tasks on the low poer cores and only spin up the hot ones when the application required the performance or binary compatibility. Think more like switchable graphics than big.little, though the low power architecture would stay usable all the time.