Messages in this thread |  | | | Date | Wed, 19 Nov 2008 15:11:38 -0800 (PST) | | Subject | Re: NIU driver: Sun x8 Express Quad Gigabit Ethernet Adapter (perf + regression IRQs) | | From | David Miller <> | |
From: Jesper Dangaard Brouer <hawk@diku.dk>
Date: Wed, 19 Nov 2008 23:58:12 +0100 (CET)
> Well that was not the real cause of the performance loss. Because
> on kernel 2.6.27 I get really good performance (900-1200kpps)
> compared to 2.6.28 (git net-2.6).>> The cause of this problem (tracked down together with Robert Olsson)
> is that on 2.6.28 I have a lot less IRQs available. It seems max 34
> IRQs.>> Due the reduced number of IRQs the NIU driver cannot get enough IRQs
> to the interfaces, and starts to use "IO-APIC" based IRQs.
This is almost certainly related to the driver unload bug.
I know you ran into unbuildable/unbootable kernels during a bisect,
but you really need to track down this regression.
There were a lot of IRQ changes, especially on x86. The sequence is
something like:
1) dyn irqs
2) APIC/IO_APIC handling integration
3) by-hand REVERT of dyn irqs, it was done by hand in order to not
lose the #2 changes
4) interrupt remapping support
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