portable-simd VS cargo-xtask

Jubilee and Caleb Zulawski for their tireless work on the portable SIMD project. It will land, some day, and when it does it's going to be an amazing boon for the project.

The portable SIMD project implements an as_simd() function for slices. The basics are that you get 3 slices and the middle one is a SIMD slice. It allows for fast aligned loads of the data, which could matter if your algorithm is becoming memory bound; it is also a convenient and safe abstraction. In my case, I actually have 2 vectors (say, x and y). I can take them apart using as_simd() like so:

Rust has generics and monomorphization. You can write the algorithm once and compile for multiple targets. rust-lang/portable-simd

This Rust issue [0] was the best short summary of what an SIMD Shuffle is I could find:

„A "shuffle", in SIMD terms, takes a SIMD vector (or possibly two vectors) and a pattern of source lane indexes (usually as an immediate), and then produces a new SIMD vector where the output is the source lane values in the pattern given.“

[0] https://github.com/rust-lang/portable-simd/issues/11

Yet by default it generates code which is only compatible with Pentium4 or newer. In fact lots of serious issues relate to older CPUs and rustc developers plan is to declare them closed when they would be able to drop i686 support (all AMD CPUs which support SSE2 support x86-64, too while Intel situation is mess).

The standard API crate for portable simd is at https://github.com/rust-lang/portable-simd, but using this requires nightly, which I don't want to do. I'd like to use a crate for simd that works on both x86_64 and wasm in stable rust. wide looks fine for this purpose. Are there any potentially better choices?

See: https://github.com/rust-lang/portable-simd

As for portable SIMD, there's relatively recent activity (last commit 20 days ago) on this repository: https://github.com/rust-lang/portable-simd

💡 Inspired by matklad/cargo-xtask and based on 🏃‍♂️ Write your Rust project scripts in task.rs from the Rust ecosystem.

Using a cargo-xtask task to generate them as a manual step (inlyne currently does this)

As someone else said just is good for that job, or you could implement an xtask helper for these things and setup a suitable development environment with that: https://github.com/matklad/cargo-xtask/

Well tools like cornucopia, prisma-rust-client, protoc-gen-tonic, they don't generate in build.rs, but instead provide either a cli to be called ahead of time, or provide a library that can be called by your own binary (which should generally follow the xtask pattern)

If I understand, this is a tool for when working on the project itself? Akin to a helper script? You could go the cargo install route as already pointed out but there is also the xtask convention.

For simple cli apps for internal use, such as cargo-xtasks, I prefer pico_args due to its fast compile times.

For developer-oriented stuff, there's tools like xshell and cargo-xtask. For operator tasks that need to run in a deployed environment, it's not usually a big lift to add CLI subcommands to your binary. It's certainly more boilerplate and inertia than doing stuff in a live REPL, though, and sometimes difficult to recommend for truly one-off situations.