Multicore processing

Two heads are better than one goes the old saying, and the same is true for computer systems, where two—or more—processors can greatly improve performance. Multiprocessing systems can be in these forms:

Discrete or traditional

A system that has separate physical processors hooked up in multiprocessing mode over a board-level bus.

Multicore

A chip that has one physical processor with multiple CPUs interconnected over a chip-level bus.

Multicore processors deliver greater computing power through concurrency, offer greater system density, and run at lower clock speeds than uniprocessor chips. Multicore processors also reduce thermal dissipation, power consumption, and board area (and hence the cost of the system).

Multiprocessing includes several operating modes:

Symmetric multiprocessing (SMP)

A single instantiation of an OS manages all CPUs simultaneously, and applications can float to any of them.

Bound multiprocessing (BMP)

A single instantiation of an OS manages all CPUs simultaneously, but each application is locked to a specific CPU.