When using a POSIX threads implementation, you have a choice of several scheduling policies: SCHED_FIFO, SCHED_RR and SCHED_OTHER.
Typically, the default is SCHED_OTHER, while using SCHED_FIFO or SCHED_RR requires special (e.g., root) privileges.
By default, GNAT uses the SCHED_OTHER policy. To specify SCHED_FIFO, you can use one of the following:
To specify SCHED_RR, you should use pragma Time_Slice with a value greater than 0.0, or else use the corresponding `-T' binder option.