G1GC Concepts and Performance Tuning
summary
Shows how to diagnose and shrink long G1 pauses by collecting GC data with Java Flight Recorder and text logging via -Xlog:gc, then correlating in Java Mission Control. Demonstrates a case where evacuation copying dominates (workers avg ~4–9 ms, one hits ~50 ms; evacuation 52.5 ms of a 54 ms pause) and a fallback full GC jumps to ~400 ms versus a 200 ms target. Recommends start-clean JVM flags, tune G1MixedGCCountTarget=8 and G1ReservePercent=10, and use recent JDKs and the G1 tuning guide.
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chapters (21)
- 0:00Intro
- 0:24Agenda
- 7:52Performance Problems
- 16:23Too long requests
- 17:05Post target
- 18:34Joints
- 20:39Logging
- 21:08Data Analysis
- 24:53Mixed Collections
- 26:15Mix GC Count Target
- 27:12Mix GC Threshold
- 29:39To Space Exhausted
- 30:32Mixed Collection
- 30:45Junk Collection
- 31:06Concurrent Marking
- 34:07Adaptive Concurrent Cycle
- 35:24Full Collection Analysis
- 36:51Summary
- 37:18Recap
- 37:37Join us
- 38:14Stop by
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