Glossary

asymmetric multiprocessing (AMP)

A separate OS, or a separate instantiation of the same OS, runs on each CPU.

bound multiprocessing (BMP)

A single instantiation of an OS manages all CPUs simultaneously, but you can lock individual applications or threads to a specific CPU.

discrete (or traditional) multiprocessor system

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

hard thread affinity

A user-specified binding of a thread to a set of processors, done by means of a runmask. Contrast soft thread affinity.

inherit mask

A bitmask that specifies which processors a thread's children can run on. Contrast runmask.

multicore system

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

runmask

A bitmask that indicates which processors a thread can run on. Contrast inherit mask.

soft thread affinity

The scheme whereby the microkernel tries to dispatch a thread to the processor where it last ran, in an attempt to reduce thread migration from one processor to another, which can affect cache performance. Contrast hard thread affinity.

symmetric multiprocessing (SMP)

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