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.
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:

Note: To determine how many processors there are on your system, look at the num_cpu entry of the system page. For more information, see "Structure of the system page" in the Customizing Image Startup Programs chapter of Building Embedded Systems.