Java Memory Consistency Model
summary
History shows the original Java memory model is broken and is corrected by JSR-133 (Java 5), with volatile, synchronized and final semantics fixed but still interacting with JVM, OS and CPU implementations. Measure performance: L1 ~0.5 ns, main memory ~100 ns, SSD ~150 µs so cache effects dominate. Practical advice: avoid false sharing by aligning/padding or filling 64-byte cache lines and run small probe tests per JVM+OS+CPU; consider Quasar/fibers for lightweight concurrency.
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chapters (11)
- 0:00Introduction and context
- 3:29Laws of computing history
- 7:55Concurrency vs parallelism
- 11:01Distributed systems and time
- 14:56Java threading history
- 17:28Understanding memory models
- 20:41Java memory model internals
- 25:31Compiler and hardware optimization
- 29:22Mechanical sympathy explained
- 33:27Advanced threading libraries
- 35:19Summary and resources
