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kayvonf

Question: What is write serialization? Someone take a crack at explaining why the MSI protocol ensures write serialization.

LilWaynesFather

It means that two writes to the same location by two processors will be seen in the same order by all processors. This is ensured because only one processor is allowed to be in the Modified state for a specific cache line. This means at most one processor is allowed to write to that cache line at a time. As soon as another processor wants to write to that cache line, the cache line is flushed and is invalidated on the original processor.

kayvonf

Good, but I'll clarity that write serialization means that all writes by all processors are observed in the same order by all processors.