Language isn’t everything. While Rust provides some features and safety that C doesn’t while being roughly equivalent in performance, the algorithms that developers choose will dominate the performance impact on the program.

GNU core utils has decades of accumulated knowledge and optimisation that results in the speed it has. The Rust core utils should in theory be able to achieve equivalent performance, but differences in the implementation choices between one and another, or even something as simple as the developers not having prioritised speed yet and still focusing on correctness could explain the differences that are being reported.

Rust and C are the same “tier” of performance, but GNU coreutils has the benefit of several decades of development and optimization that the Rust one needs to catch up with.

@Strit @rezad Memory and thread safe yes. Performance was more roughly equal, could be faster or slower depending on use case.

Rust is fundamentally more limiting than C, even with unsafe. It is often faster if you write naive code (because the Rust compiler can optimize more aggressively due to those same limitations), but an experienced developer with a lot of time for optimization will probably be able to squeeze more performance out of C than they would out of Rust - as you can see in this example. Rust is still better because those limitations all but guarantee that the resulting code will be safer, and the performance differences would be negligible all things considered.

It’s more a thing like in ripgrep vs. grep; new algorithms being vastly faster in most cases except in some.