Hierarchy changes where information lives and how traffic travels. It does not remove the need to find every conflicting permission and the newest data. Begin with what each level of directory records, follow one cross-cluster transfer, then consider die-crossing and metadata costs.
Lesson | After it you can... |
|---|---|
Read a cluster-level record and the local states it allows. | |
Trace the newest data through local proxies and one global serialization point. | |
Count die crossings on a coherence path and keep link delivery separate from protocol completion. | |
Compare illustrative metadata savings against added paths and replication. |
Read after the filtering and deadlock lessons. The lessons extend the course model with two clusters, K0 = {C0, C2} and K1 = {C1}, local proxies H0 and H1, and the original H as global home. C2 is a third core, added because local sharing needs two cores in one cluster. Extra topology does not imply a commercial protocol.
No. It can record the cluster containing a private dirty-responsible holder. A record that leads to a copy is not the copy.