Scalable symmetric multiprocessor data-processing system with data allocation among private caches and segments of system memory

A scalable symmetric multiprocessor data-processing system having a system memory, said data-processing system comprising:

• a plurality of processing units, wherein each of said plurality of processing units includes a cache memory for storing a subset of data contained within said system memory;
• a cache controller included within each one of said processing units for controlling an associated one of said cache memories, wherein said cache controller includes a mode select to allow an associated cache memory to be selectively operated under either a first mode or a second mode for indicating an address space of said system memory in which one of said cache memories can store data;
• and
• a plurality of partial system memories, wherein each of said plurality of partial system memories is associated with a respective one of said plurality of processing units, wherein an aggregate of contents within all of said plurality of partial system memories forms said system memory.