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Comment by gameswithgo | Hacker News Reader

what you are talking about isn’t the situation. they are intentionally detecting cpu features wrong so as to not use features amd cpus have. nobody is expecting special amd optimization attention.

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Ok, if it's like that ("intentionally detecting cpu features wrong") then I would agree.

Can a "CPU feature" (e.g. sse2, avx, aes, etc...) be implemented the same way between different architectures?

(Until someone has a more detailed answer) Both Intel and AMD are on the same X86 architecture, and sse2 etc are just extensions of the X86 architecture, u can check which feature flags a CPU has

And the call/use of these features is the same for AMD or Intel

They explicitly look for the "GenuineIntel" product string and then basically disable all the efficient code paths if it isn't found, totally against their own advice for ISA extension detection [1].

https://www.agner.org/optimize/blog/read.php?i=49

I'm curious if AMD could produce an internal engineering sample that simply copies all the relevant product strings from the competing vendor. They could check for statistically relevant performance discrepancies from just that modification.

don't need to make samples, you can fake the identifiers with virtualization and measure the delta.

But that has virtualization overhead. You don't want to measure that/risk being accused of measuring that.

Run both processes in a virtual environment then. Hell, that's where a lot of machines are running anyway. At least in server environments.

Also the overhead these days is pretty marginal, been running macos on an amd CPU emulating a Pentium(since macos also looked for Intel) and it beat all Mac pros of that time in cinebench etc

Sounds like user-agent strings all over again...

yes :) RDRAND is implemented differently

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