Messages in this thread | | | Date | Wed, 2 Jul 2008 13:19:39 +0200 | From | "Leon Woestenberg" <> | Subject | Re: [Ksummit-2008-discuss] Delayed interrupt work, thread pools |
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Hello,
(including linux-rt-users in the CC:, irqthreads are on-topic there)
On Wed, Jul 2, 2008 at 1:02 PM, Andi Kleen <andi@firstfloor.org> wrote: > Benjamin Herrenschmidt <benh@kernel.crashing.org> writes: > >>> how much of this would be obsoleted if we had irqthreads ? >> >> I'm not sure irqthreads is what I want... >> > I also think interrupts threads are a bad idea in many cases because > their whole "advantage" over classical interrupts is that they can > block. Now blocking can be usually take a unbounded potentially long > time. > > What do you do when there are more interrupts in that unbounded time? > If by irqthreads the -rt implementation is meant, isn't this what happens:
irq kernel handler masks the source interrupt irq handler awakes the matching irqthread (they always are present) irqthread is scheduled, does work and returns irq kernel unmasks the source interrupt
> Create more interrupt threads? At some point you'll have hundreds > of threads doing nothing when you're unlucky. > Each irqthread handles one irq. So now new irq thread would spawn for any interrupt.
Regards, -- Leon
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