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

[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". Actually, I can propose to use flags directly from the ripgrep profile.

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 9 5900x, Fedora 42, Rust 1.89, the latest version of the project at the moment, cargo build --release command, without stripping) - here are the results:

• Release (qmark): 6.7 Mib
• Release + codegen-units = 1 + Fat LTO (qmark): 4.8 Mib
• Release (quickmark-server): 9.1 Mib
• Release + codegen-units = 1 + Fat LTO (quickmark-server): 6.3 Mib

Clean build time:

• Release: 19s
• Release + codegen-units = 1 + Fat LTO: 53s

Thank you.

[ekropotin]

Thank you @zamazan4ik for bringing this up!
As I new to Rust and still learning, I wasn't even aware about this feature.
I'll definitely look into it further.
Meantime, you or anyone else reading this are more than welcome to file a PR, enabling this feature.

[zamazan4ik]

Sure! #127