ZGC: The Next Generation Low-Latency Garbage Collector
summary
ZGC is a concurrent, region-based, compacting GC that claims sub-10 ms pauses today and targets sub-millisecond max pauses tomorrow. It uses load barriers plus colored pointers to do marking and relocation concurrently (everything is concurrent except thread-stack scanning until JEP‑376). Production-ready on JDK 15, supports heaps from 8 MB–16 TB, and shows SPECjbb2015 numbers with average pauses ~0.5 ms and max ~1 ms on 128 GB, and with concurrent stack scanning down to ~0.1 ms average / ~0.5 ms max; tune heap headroom and concurrent GC threads.
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chapters (19)
- 0:00Introduction
- 2:47GC Landscape Overview
- 3:31CDC Algorithmic Overview
- 5:45Comparison with Other GCs
- 7:16Supported Platforms
- 7:32Version History and Status
- 8:22CDC Internals and Techniques
- 15:52Performance Benchmarks
- 17:23Pause Time Results
- 17:51Stress Test Results
- 18:24Latency Benefits
- 19:03Getting Started with CDC
- 25:22Future Roadmap
- 26:31Sub-millisecond Pause Times
- 26:48Generational CDC
- 30:18Learning Resources
- 31:12Conclusion and Download
- 31:34Q&A Session
- 38:52Closing and Next Sessions
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