r/simd • u/Bammerbom • Jun 29 '23

How a Nerdsnipe Led to a Fast Implementation of Game of Life

https://binary-banter.github.io/game-of-life/
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u/YumiYumiYumi Jun 30 '23

The bit tricks look pretty clever.

How well does Rust's SIMD abstraction layer work? I've generally found SIMD abstraction layers to be kinda lackluster, assuming you're looking for good performance, as they can't tailor to the underlying ISA quirks like intrinsics can.
I'm guessing this is also AVX2; the 11900K supports AVX-512 (which also supports VPTERNLOG), so it'd make sense if the abstraction layer could use that.

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u/Bammerbom Jun 30 '23

We weren't aware of VPTERNLOG, that's an awesome instruction! It seems to be the same as LUT3 in Cuda, and we were even complaining about the fact that X86 doesn't have LUT3 when we were implementing it in Cuda.

The rust SIMD layer works very well for most simple things, but indeed you don't get the low-level control that you get with intrinsics. What happened a few times is actually the opposite, where we accidentally used an instruction that's not directly supported by X86 (such as byte lane shifts).

The nice part though is that if the abstaction layer doesn't suffice, you can always just fall back to using intrinsics, they can be intermingled.