Day 2 Keynote
summary
Vernier is a sampling profiler for Ruby 3.2+ that actually records wall‑time and allocation samples together, surfaces 890,000 allocations from a bundler demo where a string split runs 200,000 times and cuts execution from ~6s to ~0.5s after avoiding allocations, and reuses the Firefox profiler frontend for visualization. It uses a C thread sample writer to avoid missed or biased samples, subscribes to GVL and GC markers, captures every running thread, and is safe enough to run in production.
AI-written summary · about
chapters (10)
- 0:00Keynote introduction
- 2:08Performance as continuous learning
- 9:58Vier Ruby profiler demo
- 19:35Measuring performance accurately
- 26:23Timeline view and Active Support
- 29:30Sampling vs tracing profilers
- 37:16StackProf limitations and fixes
- 40:46Vier’s C-thread sampling
- 44:21Profiling Mastodon with Vier
- 47:36Call to action
related talks
42mDebugging Ruby
26mHow a Ruby profiler works: Stackprof under a microscope
43mReal World Ruby Performance at Scale
37mThe Future of Ruby Performance Tooling
01h 24mKeynote
24mDIY::Thread.profile -- Light-Weight Profiling in Pure Ruby
38mProfiling Tips and Tricks
34mUnder the Hood of Ruby's Generational Garbage Collector