Why is my Rust build so slow?
fasterthanli.me
Why is my Rust build so slow?
1–10 of 217 posts
Re: Why is my Rust build so slow?
#2I loved this article!
Super informative.
Very interesting that the author managed to hit a pathological case in rustc.
Re: Why is my Rust build so slow?
#3Rust's slow compiles are such a turn off for me. Like why does it take tens of seconds to recompile when I am just changing a single number in a file? Does it really need to waste so much of my time to change a single byte in the output binary?
Re: Why is my Rust build so slow?
#4Rust's slow compiles are such a turn off for me. Like why does it take tens of seconds to recompile when I am just changing a single number in a file? Does it really need to waste so much of my time to change a single byte in the output binary?
I think speed is separate from caching, albeit overlapping. If the compiler can see exactly what changes your code will have in the final binary, then it can do very very little work. However, it would also suffice for the compiler to just be so fast that it can do a complete compile from zero to finished in some acceptable time (tcc and I think Go favor this). Those are different goals, or at least different ways of achieving the desired outcome.
Re: Why is my Rust build so slow?
#5Rust's slow compiles are such a turn off for me. Like why does it take tens of seconds to recompile when I am just changing a single number in a file? Does it really need to waste so much of my time to change a single byte in the output binary?
I believe incremental mode is still off by default.
Re: Why is my Rust build so slow?
#6Rust's slow compiles are such a turn off for me. Like why does it take tens of seconds to recompile when I am just changing a single number in a file? Does it really need to waste so much of my time to change a single byte in the output binary?
Use bazel?
Individual files won't be faster but it's been a wonder for whole project compilations
Re: Why is my Rust build so slow?
#7Rust's slow compiles are such a turn off for me. Like why does it take tens of seconds to recompile when I am just changing a single number in a file? Does it really need to waste so much of my time to change a single byte in the output binary?
I believe incremental mode is still off by default.
Not for debug builds, according to the article.
Re: Why is my Rust build so slow?
#8This article is fairly strange. The author keeps changing settings to make the release profile more like a debug profile. Wouldn't I want LTO for releases?
Also this is a really long article with a lot of cool tricks and interesting information. Like the author's binary crate, they might consider splitting this article apart. Or at least adding a TOC!
Re: Why is my Rust build so slow?
#9Rust's slow compiles are such a turn off for me. Like why does it take tens of seconds to recompile when I am just changing a single number in a file? Does it really need to waste so much of my time to change a single byte in the output binary?
Use bazel? Individual files won't be faster but it's been a wonder for whole project compilations
This could be interesting to look into. It looks like there already exists a project that can generate BUILD files for external crates.
My 2 main gripes with Bazel was that it was a pain having to rewrite the build system for all of my dependencies and that it's claim of being reproducible is weak in the sense that there are not even warnings when you use resources from the base system (eg. compilers can include files from the base system which may not be the same / exist on another) (this is a problem since I wanted to use a header from the dependency I built with Bazel and not something already on my system)
Re: Why is my Rust build so slow?
#10Rust's slow compiles are such a turn off for me. Like why does it take tens of seconds to recompile when I am just changing a single number in a file? Does it really need to waste so much of my time to change a single byte in the output binary?
Contrary to most, I actually like the long compile times.
I also like programming in Rust without a linter.
It really makes me think about what it is I'm doing. I do not have the luxury of typing something down, compiling it, and running it after every change to see: "does it work now?"
To be fair, that's only in my personal projects. I understand this is a major issue in the "ship it quickly -- everything else be damned" environment of commercial programming, where one must rely on all these aides to get something reasonably done in a reasonable amount of time.
It was a major headache when I first learned the language, because the syntax is so rigid and exacting; but it did force me to really understand the language, instead of just being able to throw shit at the wall and consult technical docs everytime I wanted to do something.