COMA multiprocessor.

As we described in the chapter, one important, but difficult, goal of a NUMA multiprocessor designer is maximizing the number of page accesses that can be serviced by local memory.Describe the three strategies, COMA, page migration and page replication, and discuss the advantages and disadvantages of each. What will be an ideal response?

A COMA multiprocessor treats all main memory as cache. The advantage of
this strategy is that it allows the system greater control over the placement of
data because it manipulates memory lines, not memory pages.This increases the
percentage of memory accesses serviced by local memory. However, it requires
a complex coherence protocol and a significant redesign of the system (hence
the name COMA, not NUMA).