Profiling Code in Rust - by Vitaly Bragilevsky - Rust Linz, December 2022

Learn how to identify and optimize performance issues in Rust code using profiling tools like Valgrind, `cargo run`, and flame graphs, and explore techniques for simplifying data structures, reducing memory allocations, and benchmarking.

Key takeaways
  • Profiling code in Rust is useful to identify performance issues and optimize program behavior.
  • Rust profiling tools are available, including Valgrind and cargo run.
  • Profile data can be visualized using flame graphs.
  • Memory allocation and deallocation are important areas to profile.
  • Simplifying data structures, such as using vec! instead of String, can reduce memory usage.
  • Efficient data structures, such as using Rc (Reference Counting) or Arc (Atomic Reference Counting), can reduce memory allocations.
  • Reducing the number of allocations can significantly improve program performance.
  • Pre-mature optimization should be avoided, and focus on understanding the problem and identifying areas for improvement before optimizing.
  • Profiling and optimization should be done iteratively, with testing and validation at each step.
  • Docker simplifies the profiling process by allowing you to run your program in a container.
  • The criterion library can be used to benchmark and profile Rust code.
  • Valgrind is a powerful tool for memory analysis, but it can be challenging to use.
  • Instruments is another tool for profiling and analyzing Rust code.
  • A simple technique for optimizing memory allocation is to resize vectors in advance.
  • Another technique is to avoid temporary structures and reuse existing data.
  • Benchmarking and profiling should be done at different levels, from simple metrics like memory usage to more complex analysis like function call frequency.