Robert Kavaler ([EMAIL PROTECTED]) wrote:
> and realtime tasks?
>
> Will the interrupt preempt the current RT task or will the interrupt be
> queued until the current task completes? I don't see any way to set a
> priority to the interrupt which leads me to think that the interrupt
> will just preempt the current task.
Yes.
> When an interrupt runs can it be preempted by the RT scheduler? (after
> all, it is just another interrupt).
No, RT interrupt handlers are non-preemptable.
>
> Do I have to size each task's stack to handle the maximum interrupt
> memory usage (i.e. all interrupts going off at the same time)?
Yes, but you don't need more than 8192 bytes, since that's the Linux kernel
stack size.
> If the interrupt does preempt, is there some easy way to implement
> queueing where the interrupt "task" can be scheduled with normal task
> priorities (i.e. create a normal task and have the interrupt wake task)?
In the real-time task, use the following loop:
while (1) {
pthread_suspend_np(pthread_self());
// handle the interrupt
}
Then install a RT interrupt handler using rtl_request_irq (there is a manual
page in the distribution).
In the interrupt handler call pthread_wakeup_np(thread) to
wake the real-time thread up.
Michael.
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