With the real-time executive approach, a small real-time kernel coexists with the Linux kernel. This real-time core uses a simple real-time executive that runs the non-real-time Linux kernel as its lowest priority task and routes interrupts to the Linux kernel through a virtual interrupt layer.
All interrupts are initially handled by the core and are passed to standard Linux only when there are no real-time tasks to run. Real-time applications are loaded in kernel space and receive interrupts immediately, giving near hardware speeds for interrupt processing.
I wonder how to test this in ordinary desktop Linux, e.g. Ubuntu? If it's even possible?
Best Answer
This sounds very much like the approach taken by RTLinux, which still seems to be available but not commercially supported.
That being said, there's a community unto itself about real-time Linux concepts, and the CONFIG_PREEMPT_RT patch would seem to enable the functionality you're looking for. As with all kernel hacking, do so at your own risk. There's a HOWTO available to help you get started.