Messages in this thread | | | From | Yevgeny Petrilin <> | Subject | RE: IRQ affinity enforced only after first interrupt. | Date | Tue, 27 Mar 2012 09:39:08 +0000 |
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> > > > > > The architecture specific code will determine whether the IRQ could be migrated > > > in process context. For example, the IRQ_MOVE_PCNTXT flag will be set on x86 > > > systems if interrupt remapping is enabled. > > > > Actually I am encountering this issue with x86, and see different > > behavior with different HW devices (NICs). On same machine I have > > one device that responds immediately to affinity changes while the > > other one changes the affinity only after first interrupt. > > That simply depends on the underlying hardware. On certain hardware we > can change the affinity only in hard interrupt context, that means > right when a interrupt of that device is delivered. > > On the other devices we can change it right away and the corresponding > interrupt chips set IRQ_MOVE_PCNTXT to indicate that. > > There is nothing we can do about this. It's dictated by hardware. >
Thanks for the explanation, Which capabilities of the HW show whether IRQ_MOVE_PCNTXT can be set or not? Is it done by reading configuration from PCI?
Thanks, Yevgeny
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