[microblaze-uclinux] reschedule problem

["Brettschneider Falk" <fbrettschneider@xxxxxxxxxxxxxxx>]

Hi,

Do you have an idea or example code how an ISR in kernel 2.6 can force a reschedule immediately after it has finished? In good old kernel 2.4 times I used current->need_resched=1 to do so.

My problem is, this happens in my self-written driver:
The interrupt service function mydriver_ISR() calls wake_up_interruptable(&queue) but I see the appropriate awaking of the sleeping user space thread at mydriver_poll() just more than 5 milliseconds later. Probably on the next timer-IRQ that triggers the scheduler?

I tried to call set_current_state(TASK_INTERRUPTABLE) before poll_wait(..,&queue,wait) in function mydriver_poll(), and to call set_tsk_need_resched(current) in the ISR, but without any improvement of that bad wakeup-latency.

With my tracing to a log buffer in memory (means: no use of printk), I can see that no other thread is scheduled next than my desired user-space thread.

Do you have any idea?

Cheers,
Falk

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