> 
> So, how exactly does an application level process go about the task of
> preempting the kernel?

It can't - after all the kernel is already running the 'best' process.

What has to happen is either:
1) A process wakes up a higher priority process
2) An interrupt wakes up a higher priority process

(A timer interrupt might cause the scheduler to re-evaluate all
the process priorities.)

On an SMP system an interrupt on one CPU might cause the scheduler
to generate an inter-cpu interrupt to force a different cpu to
process switch....

	David

-- 
David Laight: david@l8s.co.uk