This document discusses using economic concepts like demand curves and elasticity to model garbage collection in programming languages. It introduces the concept of allocation curves and elasticity to represent how memory is allocated as a program runs. Experiments were done with different garbage collection algorithms on Java benchmarks to analyze their allocation curves and how shifting the curves or adjusting elasticity can control heap growth and improve performance. Alternative heuristics for heap growth management based on allocation elasticity are proposed and evaluated based on execution times and final heap sizes.

1. The Economics of
Garbage Collection
Jeremy Singer, Richard Jones, Gavin Brown, Mikel Luján

2. Motivation

3. The main goals
• Determine allocation curve
• Introduce allocation elasticity
• Make use of introduced elasticity

4. Microeconomics demand curve

5. Garbage collection analogy

6. Empirical Allocation Curves
• Empirical data from real-world Java application
• Different algorithms from MMTk toolkit run on
JikesRVM
• Java benchmarks from DaCapo suite
• Fixed size heap 35-500 MB

7. Full-Heap Collection
• Mark-Sweep GC
• Allocation curves obey the law of allocation

8. Generational Collection
• Generational Mark-Sweep GC
• Nursery space – frequently collected
• Mature space – long-lived objects
• Added weight of 0.1 to Nursery GC

9. Shifting the Allocation Curve
• Added “tax” – additional words to object header
• Allocation curve shifted upwards

10. Elasticity

11. Controlling Heap Growth using Elasticity
• Elasticity to improve GC performance
• Controlling the expansion rate heap
• Default heuristics for controlling heap size
• Sensitivity in default heuristics
• Alternative heuristics

12. Alternative Heuristic for Heap Growth
Management
• Based on allocation elasticity
• target elasticity, E
o small E, slow heap growth rate
o large E, rapid heap growth rate

13. Execution Time Benchmarks

14. Final Heap Sizes

15. Related Work
• Stefanovic et al. used statistical techniques
• Baker offered radioactive decay model
• Garbage collection and transactional memory

16. Conclusion
• Microeconomics and memory management
• Allocation curve
• Allocation elasticity