SMP represents one of the earliest styles of multiprocessor machine achitectures, typically used for building smaller computers with up to 8 processors. Larger computer systems might use newer architectures such as NUMA (Non-Uniform Memory Access), which dedicates different memory banks to different processors. In a NUMA architecture, processors may access local memory quickly and remote memory more slowly. This can dramatically improve memory throughput as long as the data is localized to specific processes (and thus processors). On the downside, NUMA makes the cost of moving data from one processor to another, as in workload balancing, more expensive. The benefits of NUMA are limited to particular workloads, notably on servers where the data is often associated strongly with certain tasks or users.
Other systems include asymmetric multiprocessing (ASMP), which uses separate specialized processors for specific tasks, and computer clustered multiprocessing (such as Beowulf), in which not all memory is available to all processors.
Examples of ASMP include many media processor chips that are a relatively slow base processor assisted by a number of hardware accelerator cores. High-powered 3D chipsets in modern videocards could be considered a form of asymmetric multiprocessing. Clustering techniques are used fairly extensively to build very large supercomputers. In this discussion a single processor is denoted as a uni processor (UN).
Answered by
Alok Gupta
at
5:28 PM on December 27, 2008
