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Comment by bilekas | Hacker News Reader

How fast does Rust compi..... I better not actually.

Don't worry, I wrote this article about Java but my day-to-day work is Scala. We're lucky if we can crack 4,000 lines-per-second-per-core on my pretty vanilla Scala projects x_x

I feel the pain, I've started a startup on Scala (and some years later successfully sold it), but compilation speed and 20 lines type constraint errors where my biggest problems (but I never forget that it enabled us to scale the company and sell it :-) - but if a programming language spawns consulting companies that only help with speeding up compile times, that is a bad sign.

Though when working on a 2M+ LOC Java project 15 years ago, we also spent a lot of money on very fast RAID hard drives in developer machines to speed up compilation. JRebel was a huge relief back then.

Why? I'm quite curious. There aren't any good benchmarks on the internet, especially ones comparing it to other languages. I'd love to actually see some real numbers showing how far off it is from Java or Go (I don't doubt it is slower than Java or Go, as it is a much more sophisticated language).

My anecdotal evidence suggests it is not as slow as many think. It compiles a 500k LoC (that's count of all code in dependencies) project in ~10s on my M2 Pro.

Subjectively, not baked by any science, the Linking step is the worst, even with mold.

About my only gripe with the language.

But it's getting better.

One thing I discovered while trying to improve my incremental Rust compilation time (https://blog.waleedkhan.name/rust-incremental-test-times/) was that there was a lot of time that seems to have been attributable to `cargo` itself (https://lobste.rs/s/ktyp2q/improving_incremental_test_times_...), rather than the compiler. It seems like a similar situation as reported in the article.

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