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Comment by littlestymaar | Hacker News Reader

> This sample code took 12 minutes on a clean build on my travel netbook, now dead.

Clean builds are slow indeed. But they are also once every six week at most if switch to the latest compiler at every release.

> Get the community editions of Delphi, FreePascal, or D and see what a fast build means.

Honestly, who cares about the difference between 1s vs 100ms vs 10ms for a build though? Rust compilation isn't optimal by any means, and it wouldn't have been workable at all in the 90s, but computers are so fast today (even 13-years old computers) it rarely matters in practice IMHO.

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Roc team does, that was one of the reasons they dropped Rust for Zig, even though Zig is yet to reach 1.0.

As do many of us, as we know how fast builds can be with complex languages, e.g. add OCaml to the list of faster than Rust compiler toolchains, while having a ML type system.

> Honestly, who cares about the difference between 1s vs 100ms vs 10ms for a build though?

I definitely do. Not necessarily because of the 10ms vs 1s. But because of the later stage when it becomes 600ms vs 60s.

> But because of the later stage when it becomes 600ms vs 60s.

What later stage though, as I said I worked with big code bases on old hardware without issues.

I'm simply not convinced that there exist a situation where incremental rebuild of the crate you're working on is going to take 60s, at all, especially if you're using hardware from this decade.

I have a fairly small go project (100k loc) and it takes ~30sec to build.

I'd be thrilled to have it build in 300ms.

(Using a macbook pro 2019)

Consider upgrading your hardware if/when you get a chance to (obviously this is expensive). My builds (Rust not Go, but it might well be similar?) got 10x faster when I upgraded from a 2015 MBP to an M1. I suspect 2019 to M4 might be similar.

That's strange. Humongous k8s Go projects (>500k LOC) build in a third of that time. Do you have lots of deps in your `go.mod` ? Is the project abusing codegen ?

61 dependencies, no codegen. Nothing special really.

> I have a fairly small go project (100k loc) and it takes ~30sec to build.

Wait, aren't Go builds supposed to be fast?

On a Macbook M2 Pro, on a project with loads of services, 210k loc, a full rebuild takes 70 seconds. Incremental takes 36s. For one service, full rebuild in 16s and incremental 0.6s. It's not blazing fast but considering the scale of the project, it's not that bad, especially since I rarely rebuild every service at the same time.

Are you using CGo? C compilation slowness doesn't count.

I must be doing something wrong because incremental builds regularly take 30-60 seconds for me. Much more if I add a dependency. And I try to keep my crates small.

PSA: try https://github.com/rui314/mold

(Not affiliated with the project. Just switched to it and never looked back.)

As a sibling comment points out, it's likely to be mostly link time, not compilation time.

The most recent Rust version ships with `lld` so it shouldn't be the case anymore (afaik `lld` is a bit slower than the `mold` linker, but it's close, much closer than the system linker that was previously being used by default).

Apparently Bevy doesn't need that big tutorial on how to customise Rust toolchains for usable builds then.

Come on.

There's no “big tutorial” though. There's a section about compilation time performance[1] but it's arguably not “big”, and the most impactful parts of it is about linking time, not compilation time. And half of the section is now obsolete since rust uses `lld` by default.

[1] https://bevy.org/learn/quick-start/getting-started/setup/#en...

Only if you happen to be on a platform where lld is supported.

Which platform does that description excludes?

Edit: oh I get it you probably meant “where lld is set as default ” which is currently Linux only.

Lld is supported by the other platforms though, so you can just copy-paste the three lines of configuration given on the Bevy page and call it a day.

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