[CentOS] How to load balance interrupts of a NIC on the PCI-MSI-edge driver in CentOS? :(

Thanks John!,

I understand now. I think there are some NICs that have different queues
which are connected to the kernel in the form of different IRQs, and as
thus can be load balanced nicely. Ive seen that on 10GigE NICs.. but iam
wondering if by any chance you know if the one suggested can do such, or
the name of the feature Iam looking for so I can browse myself?

Alex


On 20 May 2013 23:45, John R Pierce <pierce at hogranch.com> wrote:

> On 5/20/2013 10:24 PM, Alex Flex wrote:
> > We run a reverse proxy so our CPU need for that is very small, plus we
> > get syn flooded often.. which is why we have the need to be able to load
> > between cores, i think it is justified.
>
> IRQ handlers are not reentrant, as the hardware can't deal with it.
>
> you can only have one CPU thread at a time in the IRQ handler for a
> specific device, so you might as well just handle one device with one
> CPU.   if you have several ethernet adapters, then I'd hope the IRQs
> could be distributed
>
> one device interrupting both cores would cause a lot of trouble with
> hardware contention, or it would need to be all spinlocked which would
> make it worse, you'd be CPU bound in TWO cores in spinlocks half the time.
>
> but again, a Server adapter like a Intel Pro1000 or whatever, something
> like...
> http://www.amazon.com/Intel-1000-Dual-Server-Adapter/dp/B000BMZHX2
>
> will do much better than some $5 realtek junk.
>
>
> --
> john r pierce                                      37N 122W
> somewhere on the middle of the left coast
>
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