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by CamperBob2 2172 days ago
Intel's FP performance sucked (relatively speaking), and it matter not one iota. Because absolutely nobody cares outside of benchmarks.

Today I learned that even Linus Torvalds has a bozo bit. [1] When's the last time he actually did anything with a computer?

1: https://en.wikipedia.org/wiki/Bozo_bit

1 comments

He has the history correct. Most of the CPUs that x86 beat in the market had superior FP performance; SPARCs, Alphas, PA-RISC, Itanium, etc.

> When's the last time he actually did anything with a computer?

According to Linus he completes about 30 pull requests a day. Some multiple of that in kernel builds. His $1900 32 core Threadripper speeds that process a great deal and FP contributes little to nothing.

Today people stream video+audio, encrypt+decrypt and render graphics. All of these have specialized silicon. If their AVX-512 vanished in the night almost no one would notice the next day.

Maybe we should all be astronomers and thermodynamicists writing bespoke finite element simulations and have a deep appreciation for the wonders of floating point ISAs, but that's just not the real world.

Speaking as someone who does scientific computing all day long, in part with FEM simulations, even for me AVX512 isn't usually worth it in terms of wall-clock time.
Speaking as someone else who does scientific computing all day, taking away vectorized operations would kill my performance completely.
Yes, it's pretty much useless, and Linus's reasoning will guarantee that things stay that way.
They wouldn't notice AVX512 vanishing because they never had it in the first place, as Intel hasn't shipped it in CPU people actually use for those tasks--just servers and random laptops.

As for the rest, you are wrong, AVX/512 is not just floating point by any means, and floating point is used by more than just scientific workloads.

Games/simulations/modeling software etc all can make heavy use of floating point.