How are Method Calls Formed?

on YouTube ↗49m

" summary

Shows how Ruby resolves method calls from bytecode into C and claims a speedup by adding a polymorphic inline cache. Implements the cache as a short array (an 186 line diff), instruments MRI with a TracePoint logger and runs real workloads (1,600 requests producing ~4 million calls). Benchmarks show microbenchmarks improve but the production trace reveals most call sites are monomorphic so the patch yields little net benefit; discovers RSpec and EventMachine patterns that cause cache churn.

AI-written summary · about

" chapters (13)

1. 0:00Introduction
2. 7:58Method call sites in Ruby
3. 13:40Ruby VM executes method calls
4. 18:54Method lookup and inheritance
5. 21:42Speeding up with inline caching
6. 23:29Breaking method caches
7. 27:24Detecting cache misses with stats
8. 30:18Cache breaks and Singleton classes
9. 33:10Polymorphic calls and performance
10. 36:20Polymorphic inline caches
11. 37:46Measuring optimization impact
12. 40:52Analyzing call sites in production
13. 45:51Lessons learned

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