A method and apparatus are provided for implementing a cache state as
history of read/write shared data for a cache in a shared memory multiple
processor computer system. An invalid temporary state for a cache line is
provided in addition to modified, exclusive, shared, and invalid states.
The invalid temporary state is entered when a cache releases a modified
cache line to another processor. The invalid temporary state is used to
enable effective optimizations within cache coherent symmetric
multiprocessor (SMP) systems of an SMP caching hierarchy with distributed
caches with different caching coherency traffic profiles for both
commercial and technical workloads.