In linux kernel, enabling PREEMPT_RT will provide bounded latencies and realtime APIs. Besides configuring PREEMPT_RT, the SCHED_FIFO and SCHED_RR policies also need to be selected. And the applications need to set realtime parameters by calling appropriate APIs or by using appropriate utilities.
According to a free-electrons training: Realtime in Embedded Linux, PREEMPT_RT was a project that brings realtime capability into kernel. It has folded fully into 2.6.33 and 3.0 kernel stream. See the document you’ll find everything.
Basically there have been two approaches to bring realtime capability to linux kernel:
- Modify inside the kernel, that is PREEMPT_RT project.
- Run the realtime part side-by-side with a normal kernel and below the normal kernel, there have been three generations: RTLinux, RTAI, and Xenomai.