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Comment by n00b101 | Hacker News Reader

The general term for that is Dark Silicon [1]. It helps a little and as, others have pointed out, Intel CPUs already have a similar feature called "Turbo Boost." NVIDIA processors also have a similar "GPU Boost" feature. But I don't know if that can enable a single core to run at 10GHz. Shutting off other cores does not lower the local power density / thermal dissipation of the single core at 10GHz. You still have to work hard to cool that single core, in order to prevent the silicon from being damaged.

[1] https://en.wikipedia.org/wiki/Dark_silicon

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Right, but the suggestion is that when "one core" is running, you switch around which core it is that's actually hot, so they're taking turns generating the heat.

Obviously there's some cost there in sharing registers, cache, etc, but it's an interesting notion.

I see, that is an interesting notion. But how do you "share registers" at 10 GHz, without massive stalls during context switches? The suggestion seems require that the cores are separated by some considerable physical distance, in order to allow for heat dissipation. However this distance also means that data sharing between the cores would be slow and also very power intensive in itself. I'm not a chip designer though, just wildly guessing.

I don't think you'd need to. I expect you'd be able to run the core very fast for a number of milliseconds before having to switch.

If performed at the hardware level, you may also get some improvement by having the core push its register and low level cache state directly to the next processor, rather than have them pull the data through shared cache or RAM. Unlike a typical context switch, the process is not being resumed from idle, but has an active cache state.

The Windows Kernel already does this automatically, at a period of around 10-100ms. If you look at a single threaded program it will actually utilise all cores not one, by default its not locked affinity and the thread skips around.

Interesting, do you have a source for this? I'm curious to know more about the rationale for doing such a thing.

The Linux kernel does the same thing. Run htop and run a single threaded workload. You'll see it migrate around between all the cores.

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