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mitnk / cicada

An old-school bash-like Unix shell written in Rust
https://hugo.wang/cicada/
MIT License
981 stars 50 forks source link

Enable Link-Time Optimization (LTO) #50

Closed zamazan4ik closed 1 month ago

zamazan4ik commented 1 month ago

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.

I suggest enabling 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 additionally 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 performant version of the application. Using ThinLTO should also help to reduce the build-time overhead with LTO. If we enable it on the Cargo profile level, users, who install the application with cargo install, will get the LTO-optimized version "automatically". E.g., check cargo-outdated Release profile.

Basically, it can be enabled with the following lines:

[profile.release]
lto = true

Thank you.

P.S. It's more like an improvement idea rather than a bug. I created the issue just because the Discussions are disabled for the repo for now.

mitnk commented 1 month ago

Hi @zamazan4ik, I didn't know this option. Thanks for pointing this out!

I also read there is a lto = "thin" option, do you think true is better here?

zamazan4ik commented 1 month ago

Thanks for pointing this out!

You are welcome!

I also read there is a lto = "thin" option, do you think true is better here?

There are two major LTO kinds: Full (aka Fat) and Thin. Fat LTO allows the compiler to perform better optimizations in general compared to Thin but requires more memory during the building process and executes slower. So if you don't have huge problems with the build time for release binaries - just use Fat LTO (enabled with lto = "fat" or lto = true - they are synonyms), otherwise use ThinLTO.

IMO, for cicada you should be fine with Fat LTO.

mitnk commented 1 month ago

Yeah, had a quick check: thin produces about the same binary size and the compile time is both ~29s on my host (given we already have strip = true). While true produced small in size (4.7M vs 5.3M), and took ~40s.

mitnk commented 1 month ago

I'm closing this - lto is added in master. Thanks!