Software Concepts: Distributed Shared Memory Systems

Since a Multiprocessor system seems to be more difficult to program for, thus distributed shared memory came. Shared Memory in distributed shared memory system divides shared memory into pages and pages are distributed among machines.
Below is a diagram,

a) Pages of address space distributed among four machines.
b) Situation after CPU 1 references page 10.
c) Situation if page 10 is read only and replication is used.

False sharing occur when processors write to a shared cache line but not at the same location: there is no real coherency problem since processors write to different location and since the cache allocate a line when a write misses the protocol makes each processor invalidate the other forcing reload of a cache line at each write.

False sharing of a page between two independent processes.