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. 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. If you think that a regular Release build should not be affected by such a change as well, then I suggest adding an additional dist or release-lto profile where in addition to regular release optimizations LTO will also be added. Such a change simplifies life for maintainers and others interested in the project, persons who want to build the most optimized version of the application - and for devs we can create a dedicated [profile.optimized-dev] profile where LTO will be disabled. However, 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 E.g., check cargo-outdated Release profile.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:

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

I have made quick tests (Fedora 41, Rust 1.84, the latest version of the project at the moment) - here are the results:

• Release (current default): 3.9 MiB
• Release + codegen-units = 1 + Fat LTO: 2.7 MiB

Thank you.

[an-dr]

Appreciate the detailed explanation 🤝. The release build suffers only slightly, so will go with the full optimization for release and no change for debug.