Ractor on Ruby 3.4
summary
Ractor brings isolated object spaces to Ruby for parallelism but faces concrete limits: many gems and core code refuse to run inside Ractors, require/pp breaks cross-Ractor loading, and current GC interactions make parallel workloads very slow under GC. Ruby 3.4 adds compatibility fixes, a lcore_require proxy to delegate requires to the main Ractor, lightweight Ractor/thread improvements, and performance tuning; microbenchmarks show a specific case reaching 3.7× speedup, but production readiness still needs GC and ecosystem work.
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chapters (8)
- 0:00Introduction
- 3:41What is Ractor
- 8:30Parallel programming philosophy
- 14:45Shared mutable objects
- 17:13Ractor isolation
- 20:57Ractor limitations
- 24:13Ruby 3.4 Ractor improvements
- 27:53Ractor future plans
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