> Compiling stalwart takes about 20 minutes

20 minutes! What hardware is this on? I've worked on Rust projects with similar numbers of dependencies where the compile time (for a clean release build) was 2-4 minutes (on a MacBook M1 Pro)

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nicoburns 6 hours ago | parent [-]

UPDATE: tried compiling stalwart on my machine, and it took 14 minutes, with a really weird timing profile:

- 99% of the ~700 crates were done compiling in about a minute or 2 - RocksDB (a C++ dependency) was 2 minutes by itself - And then it took 10 minutes (ten!) just for the final binary at the end.

That's not normal for Rust code at all. Even large ones like Servo or Rustc or Zed.

UPDATE2: turns out they have LTO enabled by default. Disabling that brings the compile time down to 7 minutes. But that's still really unexpectedly slow.

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josephg 4 hours ago | parent [-]

Disabling codegen units = 1 speeds up the compilation further. But it’s still too many dependencies and too slow. The binary is pretty huge too.

	▲	nicoburns 2 hours ago \| parent [-]
		> But it’s still too many dependencies and too slow. I definitely agree that it's too slow. I just don't think the cause is "too many dependencies" because I've compiled Rust codebases with twice as many dependencies in half the time! It seems to produce a 94MB binary. So it may be partly that there are some very big dependencies. But the amount of compilation time that ends up in the top-level crate (even with LTO disabled) also makes me feel like this must be triggering a compiler bug. Either that or using far too many generics.