The FX class provides a fixed-priority preemptive scheduling policy. This policy is used by processes that require user or application control of scheduling priorities but are not dynamically adjusted by the system. By default, the FX class has the same priority range as the TS, IA, and FSS classes. The FX class allows user or application control of scheduling priorities through user priority values assigned to processes within the class. These user priority values determine the scheduling priority of a fixed-priority process relative to other processes within its class.
The scheduler manages fixed-priority processes by using configurable parameters in the fixed-priority dispatch parameter table fx_dptbl(4). This table contains information specific to the fixed-priority class.