Re: IRQ splitting

From: Lennart Sorensen
Date: Thu Apr 05 2007 - 10:14:44 EST


On Thu, Apr 05, 2007 at 12:40:57PM +0200, Jan Engelhardt wrote:
> let's take the following /proc/interrupts dump (CPU2,CPU3 trimmed)...
>
> CPU0 CPU1
> 0: 37041766 37038991 IO-APIC-edge timer
> 1: 10 2 IO-APIC-edge i8042
> 8: 0 0 IO-APIC-edge rtc
> 9: 0 0 IO-APIC-level acpi
> 12: 114 0 IO-APIC-edge i8042
> 14: 25219 5800049 IO-APIC-edge ide0
> 201: 260381 238454 IO-APIC-level aacraid
> 209: 0 0 IO-APIC-level ohci_hcd:usb1
> 217: 0 0 IO-APIC-level ehci_hcd:usb2
> 225: 57531742 0 IO-APIC-level eth0,radeon@pci:0000:03:00.0
> 233: 26 0 IO-APIC-level eth1
> NMI: 1661 1397
> LOC: 147579966 147579949
> ERR: 0
> MIS: 0
>
> My question is whether it is possible that eth0's interrupts go to CPU0
> and radeon's to CPU1, and if so, how I would enable that. Alternatively,
> is it possible to just move eth0 or radeon to a different interrupt?

Check the motherboard manual. Sometimes they explictly list which slots
share IRQs (And by share I mean are physically tied to the same wire).
I know many Asus boards have that information in the manual.

So in many cases other than changing slots, there is nothing you can do
to change the IRQ sharing, since the slots are physically sharing the
interrupt.

--
Len Sorensen
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