Symmetric Agent Arbitration—Democracy at Work
A symmetric system is one in which any processor is capable of handling (i.e., executing) any task. The job of the SMP (symmetrical multiprocessing) OS is to attempt to keep all of the processors equally busy at all times (in other words, executing various tasks). At a given instant in time, one or more of the logical processors may require ownership of the Request Phase signal group in order to communicate with an external device. In a well-balanced system, the bus arbitration scheme used to decide which of the processors gets ownership next is based on rotational (symmetric) priority—each of the processors has equal importance.