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Comment by devnullbrain | Hacker News Reader

I want to measure the device how I use it. Race-to-sleep and power states are integral to CPU design.

Yes they are, but only one of those is at all affected by the choice of ISA. If modern AMD chips are better at race-to-sleep than an Apple M1 and still get worse battery life then the problem is clearly not x86-64.

Right, so as I understand it people see that x86-64 designs score poorly on a set of benchmarks and infer that it is because they are x86-64.

In fact it’s because that manufacturer has made architectural choices that are not inherent to the x86-64 ISA.

And that’s just hardware. MacOS gets roughly 30% better battery life on M series hardware than Asahi Linux. I’m not blaming the Asahi team, they do amazing work, they don’t even work on many of the Linux features relevant to power management, and Apple has had years of head start on preparing for and optimising for the M architecture. It’s just that software matters, a lot.

So if I’m reading this right, ISA can make a difference, but it’s incremental compared to the many architectural decisions and trade offs that go into a particular design.

> So if I’m reading this right, ISA can make a difference, but it’s incremental compared to the many architectural decisions and trade offs that go into a particular design.

This is true, but only in the sense that is very rarely correct to say “Factor Y can’t possibly make a difference.”

Does anyone care about blaming / lauding an ISA without any connection to the actual devices that people use?

Performance and battery life are lived experiences. There’s probably some theoretical hyper optimization where 6502 ISA is just as good as ARM, but does it matter?

In this thread, it does. You are moving the goalpost by making this about "actual devices", when the topic is ISA efficiency.

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