Parallel Computer Architecture

8.10 Advanced Topics 665

Inter-ring

FIGURE 8.39 Block diagram for a hierarchical ring-based multiprocessor. In the

two-level hierarchy shown, each local ring is a node as viewed by the global

ring,

and an

inter-ring interface propagates relevant transactions between the two.

of the directory information in hierarchical directories is not found by going to a

fixed node. The locations of copies are found neither at a fixed home node nor by

traversing a distributed list pointed to by that home. Invalidation messages are not

sent directly to the nodes with copies. Rather, all these activities are performed by

sending messages up and down a hierarch ...