Private caches stay correct through coherence protocols that enforce a single-writer invariant. Ordering rules then decide when one core observes another core's accesses, with fences restoring guarantees where buffering and speculation reorder them.
Topic | Lessons | Description | Time |
|---|---|---|---|
5 | How private caches stay coherent: MESI states, fabrics, ACE and CHI, and triage. | 40 min | |
4 | What each memory model guarantees, where reordering comes from, and how fences fix it. | 30 min |
Ordering. Coherence gives a single value view per address over time, but the order in which cores observe different addresses follows the memory model. Missing fences let store buffers and speculation expose reorderings that the litmus tests in the Memory Ordering Models topic make executable.