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A comment on Rust in Linux kernel is just a beginning. Parent comment

Re:Rust in Linux kernel is just a beginning by rob74 on Tuesday October 25, 2022 @05:31AM (#33328253)
Thanks for that link! That sounds like the really major factor is the decision to recompile the entire crate when a file in the crate changes. I'm sure that made sense at the time ;) And, if slow compilation is such a pain point, I wonder why it takes seven years and counting to fix this bad decision - incremental compilation might have its edge cases and pitfalls, but other compilers are doing it just fine, so it shouldn't be rocket science?

Other reasons:

- suboptimal LLVM IR code, as you mentioned, and other tech debt

- the preferred strategy of monomorphising generics is fast at runtime, but slow to compile, using trait objects is faster

- the complex type system of course also plays a part

- LLVM itself is of course not optimized for Rust

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Re:Rust in Linux kernel is just a beginning by asoneth on Tuesday October 25, 2022 @08:30AM (#33329614)
> if slow compilation is such a pain point, I wonder why it takes seven years and counting to fix this bad decision

I'm not sure it was a "bad decision" if it was something that can be addressed after the fact and allowed them to ship working software more quickly.

The vast majority of the popular projects I am aware of have this kind of technical debt, likely due to survivorship bias. Project teams that refuse to take on technical debt are rarely successful enough to become popular.

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Re:Rust in Linux kernel is just a beginning by rbanffy on Wednesday October 26, 2022 @06:19AM (#33341777)
> if slow compilation is such a pain point, I wonder why it takes seven years and counting to fix this bad decision

Maybe we are giving Rust developers computers that are too fast. ;-)

OTOH, it's always wise to design for the future, so it also makes sense to give Rust developers beefy server grade hardware so they can play with SIMD pipelines and all those extra cores and threads, because that's what workstations will be a couple years from now.

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