rust-simd

Benchamrking SIMD operations in Rust The SIMD operation currently only works on avx2-compatible processors.

Usage

Nightly Rust is required (for target_feature = 'avx512f').

rustup toolchain install nightly
rustup override set nightly

Run the tests: cargo test

Run the benchmark: ARRAY_LENGTH=<> cargo bench ARRAY_LENGTH defaults to 256. Add -- --nocapture to get the test/bench outputs

Adding a benchmark

Rust code

Create a regular function to compare to. Add a bench for it in benches/bench.rs and add it to the correct criterion_group!:

fn bench_addRegular(c: &mut Criterion) {}

Create a test fonction to compare the SIMD results to the regular ones.

    #[test]
    #[cfg(target_feature = "avx2")]
    fn test_benchname() {}

Add the SIMD code. If in C, import it with

#[cfg(target_feature = "avx2")]
extern "C" {
    fn benchSIMD256_C(a: *const i32, b: *const i32, c: *mut i32, size: i32);
}

and call it from Rust with the proper pointer casting.

Create a bench for it:

    #[bench]
    #[cfg(target_feature = "avx2")]
    fn bench_SIMD: &mut Bencher) {}

Run the benchmarks

First test that your results are coherent

ARRAY_LENGTH=<> cargo test <testname>

Try a benchmark

ARRAY_LENGTH=<> cargo bench <benchname>

Use the runner to run on multiple sizes (multiplied by 2 at each iteration)

./run_criterion.py <minsize> <maxsize> [extra cargo args]