Re: CONFIG_IRQBALANCE for 64-bit x86 ?

[Andi Kleen]

Nick Piggin <nickpiggin@xxxxxxxxxxxx> writes:
>
> For that matter, I'd like to know why it has been decided that the
> best place for IRQ balancing is in userspace.

There is a lot of possible policy in it 

> It should be in kernel
> IMO, and it would probably allow better power saving, performance,
> fairness, etc. if it were to be integrated with the task balancer as
> well.

Integrating with the task balancer makes really only sense if the
device supports MSI-X and if it does that you don't really need
an irq balancer because you can just send to all CPUs as needed.

Without MSI-X you would be trying to reprogram the interrupts
all the time when a task is migrating and it is highly doubtful
that doing that automatically would do any good.

-Andi

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