Messages in this thread | | | Date | Fri, 27 Feb 2004 11:15:32 +0100 | From | Helge Hafting <> | Subject | Re: Why no interrupt priorities? |
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Grover, Andrew wrote: > > Is the assumption that hardirq handlers are superfast also the reason > why Linux calls all handlers on a shared interrupt, even if the first > handler reports it was for its device? > No, it is the other way around. hardirq handlers have to be superfast because linux usually _have to_ call all the handlers of a shared irq.
The fact that one device did indeed have an interrupt for us doesn't mean that the others didn't. So all of them have to be checked to be safe.
If this becomes a performance problem, make sure that no _busy_ irqs are shared. The easy way is to shuffle pci cards around, or set jumpers/switches or software controlled options. Or resort to reprogramming the APIC in extreme cases.
Helge Hafting
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