OpenJDK: In the new age of Concurrent Garbage Collectors
summary
Compares G1, ZGC and Shenandoah by algorithm and measurable tradeoffs: G1 is regionalized and generational with stop‑the‑world compaction and a 200 ms pause goal; ZGC and Shenandoah are regionalized, non‑generational and perform concurrent compaction using load/write barriers and forwarding pointers in object headers. Explains thread‑local handshakes (JDK10+) that replace full safepoints, humongous region handling, memory overhead from forwarding tables, and recommends GC‑log visualization tools (JClarity mentioned) and reading OpenJDK JEPs for tuning.
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chapters (11)
- 0:00Introduction
- 1:45Overview
- 3:30Stop the world vs concurrent connections
- 8:44Regionalised heap
- 11:44Copying collector
- 15:19Regions
- 23:29Comparison
- 26:38GC Phases
- 32:41GC Threads
- 41:18Shenandoah
- 45:53TVB 2015
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