Add the rust linking post

_posts/2020-01-08-faster-rust-linking.md

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+---
+layout: post
+title: "Slightly faster linking for Rust"
+tags:
+- otto
+- rust
+---
+
+Build performance has always been important to me, but my pain tolerance has
+always varied widely depending on the project. The projects I have worked on
+which require the JVM, such as [Jenkins](https://jenkins.io) or
+[JRuby/Gradle](http://jruby-gradle.org), anything under 30 seconds seems
+amazing. For small Node and Ruby projects, anything over a few seconds feels
+atrocious. Since I've been hacking with [Rust](/tag/rust.html) lately, I
+haven't been able to figure out what constitutes "acceptable."  For my
+relatively small project, incremental compilation was very quick, but for some
+reason *linking* the project would talk almost **10 seconds**. That seemed
+pretty unacceptable.
+
+
+My first course of action for things I don't understand hasn't really changed
+much in the last 15 years: I go complain and look pitiful on IRC. Fed up with
+this link time adversely affecting my test-driven development workflow in Rust,
+I visited `##rust` on the [Freenode](https://freenode.net) network and asked
+for some tips on how to improve link time.
+
+Unfortunately nobody had any good suggestions for measuring or understanding
+link time, but since [Otto](https://github.com/rtyler/otto) is open source, I
+shared the repository and a couple lurkers in the channel were able to
+reproduce the link time, and we all decided: _yes, this is way too slow_. One
+suggestion was to try the CLANG linker, rather than use the default GNU `ld`
+linker.
+
+We were all independently able to very that using `lld` brought the link time
+from **10s** down to just around **3s**, which is a great improvement! This
+change can be codified for Cargo for the snippet below:
+
+
+**.cargo/config**
+```toml
+# Dramatically increases the link performance for the eventbus
+[build]
+rustflags = ["-C", "link-arg=-fuse-ld=lld"]
+```
+
+Cargo can [be configured at multiple
+levels](https://doc.rust-lang.org/cargo/reference/config.html#hierarchical-structure),
+but for my project I opted for `$GITROOT/.cargo/config` rather than adding a
+user-global Cargo configuration. I don't believe there is any downside to
+making it a user-global, but in my case I wanted to check the configuration
+into the project to make sure that other contributors would benefit from the
+change as well.
+
+
+Three seconds for linking my relatively small sample project still _feels_ a
+bit long, but then I remind myself that I'm pulling in approximately 255 crates
+(!) as dependencies, and that's a _lot_ of linking that needs to be done by the
+compiler, even for incremental builds!
+
+If you're looking for faster link-time with Rust, try `lld`, and if that
+doesn't work, remove some of the fatter dependencies! :)

tag/yubikey.md

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+---
+layout: tag_page
+title: "Tag: yubikey"
+tag: yubikey
+robots: noindex
+---