Last compiling step only uses 1 CPU

1

When nearing the last step of compiling a Rust project, Rust uses 1 CPU. Up until then, it uses all available CPUs. I think it's linking all the different libraries together to build the final executable.

Here's an example program I was struggling with today: GitHub - rustic-rs/rustic: rustic - fast, encrypted, and deduplicated backups powered by Rust

Why can't this be done using all CPUs? It's very slow on my machine.

2

By default, Rust uses the linker provided by the platform, so it does not control how that process proceeds. Depending on your OS, there may be a faster third-party linker that you can use.

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3

In particular, mold as a linker and sccache as a general compilation cache can substantially improve things, but I'm not sure if mold will work on macOS and it certainly won't work on Windows.