Lifetime Dispersion and Generational GC: An Intellectual Abstract

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" summary

Argues that lifetime dispersion (not “most objects die young”) predicts when generational GC helps, quantifies it with the Gini coefficient derived from the Lorenz curve, and links time and space via Little’s law. Gives concrete counterexamples: a queue where all objects have identical lifetime (gen GC hurts), the same queue with 25% short-lived drops (tiny nursery wins), and Baker’s exponential-lifetime case (generationalness can hold yet gen GC fail). Provides a simple collector model proving high G suffices; measurement requires object-lifetime traces (Merlin suggested).

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" chapters (12)

1. 0:00Introduction
2. 1:13Generational hypothesis
3. 3:22GC failure example
4. 5:51Baker’s lifetimes
5. 8:20Generational hypothesis limits
6. 9:23G metric introduction
7. 11:30Lifetime dispersion
8. 13:59Time-space with Little’s law
9. 15:24Gini coefficient
10. 16:46G compositionality
11. 17:50G metric advantages
12. 18:16Q&A