Re:Observing the A11's Heterogenous Cores
by leggomylibro on Friday November 10, 2017 @10:15PM
(#15674813)
I have no idea how CPUs work, but MCUs do sorta work like how they describe; want to save power? You can easily tell the chip to cut power/clock to certain peripherals, change stuff like core clock speed and memory access latencies, make some peripherals run at lower or higher clock speeds than the core, etc etc.
You get really fine-grained control that allows a powerful and beefy chip to achieve really good power efficiency if the application is well-written, and a sleek ultralight 1.8V chip to devour power if it isn't.
Re:Observing the A11's Heterogenous Cores
by mikeash on Friday November 10, 2017 @11:02PM
(#15674938)
I believe CPUs are similar to some extent. Modern ones can clock up and down, and computing units which aren't in use can be shut down. (An example of this that's getting a lot of attention right now is Intel's AVX-512 unit, which puts out so much heat they have to clock the entire CPU down when it's in use.)
Apparently current designs can't quite do this enough, though. I'd definitely like to know the reason for that.
I would like to note, though, that the A11's high-efficiency cores are still pretty fast. In this (highly artificial) benchmark, they were able to accomplish more work in the same time than the high-performance cores. Since there's twice as many of them, that means they're at least 50% as fast on this code. So I don't know if this really will be the future, but the "slow" ones aren't useless by any means.