Trash Talk - Exploring the Memory Management in the JVM
summary
Covers concrete JVM collectors, tradeoffs and numbers: serial GC uses one thread and often runs on tiny nodes or <1.8 GB defaults; parallel GC gives throughput by using all cores; CMS is removed; G1 default: regions 1–32 MB, pause targets <200 ms (typically 50–100 ms), sweet spot ~16–32 GB heap; Epsilon is a no-GC allocator that crashes on OOM; ZGC/C4 (and Shenandoah) are concurrent regioned collectors aimed at 100+ GB heaps using cheap barriers (one-cycle loaded-value barrier) for low latency.
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chapters (18)
- 0:00Memory management intro
- 1:11Stack frames and heap basics
- 3:39Garbage collection live objects
- 5:26Stop-the-world pauses
- 7:17Mark and sweep GC
- 9:24Mark and compact GC
- 11:51Copy collector benefits
- 14:20Generational GC overview
- 18:58Concurrent GC challenges
- 24:40Serial GC use cases
- 26:03Parallel GC throughput
- 27:27CMS collector
- 28:28G1 collector
- 30:15Epsilon no-op GC
- 31:17Shenandoah concurrent garbage collector
- 32:42ZGC and C4 collectors
- 36:19Choosing the right GC
- 37:27Q&A
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