Enable Link-Time Optimization (LTO) and codegen-units = 1

[zamazan4ik]

Hi!

I noticed that in the Cargo.toml file Link-Time Optimization (LTO) for the project is not enabled. I suggest switching it on since it will reduce the binary size (always a good thing to have) and will likely improve the application's performance a bit. If you want to read more about LTO and its possible modes, I recommend starting from this Rustc documentation.

I think you can enable LTO only for the Release builds so as not to sacrifice the developers' experience while working on the project, since LTO consumes an additional amount of time to finish the compilation routine. In this case, we can create a dedicated [profile.optimized-dev] profile where LTO will be disabled (so developers experience will not be affected). If we enable it on the Cargo profile level for the Release profile, users, who install the application with cargo install, will get the LTO-optimized version of the app "automatically". E.g., check cargo-outdated Release profile. You also could be interested in other optimization options like codegen-units = 1 - it also brings improvements over the current defaults.

Basically, it can be enabled with the following lines to the root Cargo.toml file:

[profile.release]
codegen-units = 1
lto = true

I have made quick tests (AMD Ryzen 5900x, Fedora 42, Rust 1.86, the latest version of the project at the moment, cargo build --release command) - here are the results:

• Release: 6 Mib, clean build time: 15s
• Release + codegen-units = 1 + Fat LTO: 4.3 Mib, clean build time: 30s

Thank you.