Cargo Features

[dependencies]
blake2b_simd = { version = "1.0.2", default-features = false, features = ["std", "uninline_portable"] }
default = std

The std feature is set by default whenever blake2b_simd is added without default-features = false somewhere in the dependency tree.

std default
uninline_portable

This crate does a lot of #[inline(always)]. For BLAKE2b on ARM Cortex-M0 (and presumably other tiny chips), some of that inlining actually hurts performance. This feature disables some inlining, improving the performance of the portable implementation in that specific case.