Sean Klein, Rain Paharia, and Steve Klabnik join Bryan and Adam to discuss accelerating Rust builds, analyzing slow spots, cargo challenges, monomorphization, Buck 2 limitations, and Russ Analyzer improvements.
Using tools like cargo hakari can minimize unnecessary rebuilding of dependencies and improve build times in large workspaces.
Understanding the impact of proc macros and build scripts on build times is crucial for optimizing compile times.
Cargo self-profiling allows for in-depth analysis of the build process, enabling further optimizations based on specific steps, modules, and functions involved in the compilation.
Investment in tooling that provides detailed insights into code contributions to longer build times, alternative crate exploration, and linker performance can significantly improve build speed and efficiency.
Deep dives
The impact of cargo build process on compile times
The cargo build process can cause significant rebuilds when specific dependencies are built in different ways or when certain features are enabled or disabled. This often leads to unnecessary rebuilding of crates and increased compile times.
Improving build times by managing workspace hack crates
By automating the use of workspace hack crates through tools like cargo hakari, unnecessary rebuilding of dependencies can be minimized. This reduces build times and improves overall efficiency in large workspaces.
Understanding the impact of proc macros and build scripts
Proc macros and build scripts can significantly impact build times. Understanding the specific dependencies and settings related to these features is crucial in optimizing compile times.
Analyzing build process using cargo self-profiling
Cargo self-profiling allows for in-depth analysis of the build process by generating a JSON file that provides insights into specific steps, modules, and functions involved in the compilation. Further tools and analysis can be developed to optimize build times based on this information.
The need for better insight into build times
The podcast episode discusses the importance of having better analysis and insight into build times in Rust projects. It is highlighted that the current tooling is more focused on improving the speed of the Rust compiler itself rather than helping developers understand the build times of their own crate. The speaker expresses the desire for tooling that can provide detailed information on which parts of the code contribute to longer build times, such as the impact of using serializer and deserializer across structs. The need for more support and investment in this area is emphasized.
Exploring alternative crates and libraries
The episode delves into the speaker's exploration of alternative crates and libraries as potential options to address the challenges they faced. Specifically, the focus is on understanding the trade-offs between using a more generic approach like serde versus using libraries that are more tailored to specific use cases. The speaker acknowledges that while serde is a powerful tool, its flexibility and generality can come with a cost in terms of increased code generation and compile time. This leads to a realization of the value of alternatives and the need to consider specific use cases and performance requirements when choosing libraries.
Linker times and the impact on build speed
The podcast covers the issue of linker times and their impact on build speed, particularly when dealing with large static executables in Rust projects. The speaker highlights that the default system linker can become a bottleneck towards the end of the build process for certain crates with a significant number of files. They discuss the introduction of alternative linkers like LLD and Mold, with Mold proving to be the most effective in reducing build times significantly. The potential benefits of distributed caching and using multiple cores in the context of buck2, a build system, are also mentioned as potential solutions for optimizing build speed and linker performance.
We love Rust at Oxide, but the haters aren’t wrong: builds can be slow. Bryan and Adam are joined by Sean Klein, Rain Paharia, and Steve Klabnik to discuss techniques for analyzing and accelerating Rust builds.
If we got something wrong or missed something, please file a PR! Our next show will likely be on Monday at 5p Pacific Time on our Discord server; stay tuned to our Mastodon feeds for details, or subscribe to this calendar. We'd love to have you join us, as we always love to hear from new speakers!
Remember Everything You Learn from Podcasts
Save insights instantly, chat with episodes, and build lasting knowledge - all powered by AI.
