Threaded Interrupts


To make RT predictable again we can downgrade interrupts
If the interrupt is a thread (a process) it can be scheduled
And it can be prioritized above or below normal tasks


     https://lwn.net/Articles/302043/ (a.d. 2008)


It's simpler done than said
The top half disables the interrupt and awakes the IRQ thread
The IRQ thread (process) serves the interrupt and enables it again

This means your top-priority task as a predictable WCET
It is it's real (cpu-intensive) WCET
Plus one interrupt time (1-2 us) for each device

Network bursts or other massive I/O won't interfere any more