Re: [patch] 2.4.19-pre10-ac2: O(1) scheduler merge, -A3.

From: Zwane Mwaikambo (zwane@linux.realnet.co.sz)
Date: Mon Jun 17 2002 - 04:34:33 EST


<Martin Bligh added to CC>

On Mon, 17 Jun 2002, Ingo Molnar wrote:

> irqbalance uses the set_ioapic_affinity() method to set affinity. The
> clustered APIC code is broken if it doesnt handle this properly. (i dont
> have such hardware so i cant tell, but it indeed doesnt appear to handle
> this case properly.) By wrapping around at node boundary the irqbalance
> code will work just fine.

I agree, Also we have to be careful about the usage of cpu_online_map in
balance_irq, there might need to be a bit of reworking of some of the
other parts to get this working e.g. being able to determine which node a
specific IOAPIC register is on (perhaps there might be 1 or 2 IOAPICs /
node) etc etc. Martin?

> i agree that this could be a problem, but set_ioapic_affinity() can be
> made dependent on the actual NUMA setup that is used. This is absolutely
> needed anyway for a proper /proc/irq/*/smp_affinity feature.

Agreed.

Thanks,
        Zwane

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