Re: Gigabit/SMP performance problem

Ron cooper
2003-01-03T21:41:05Z

On Friday 03 January 2003 12:05 pm, Martin J. Bligh wrote:

> Dual what Xeon? I presume a P4 thing. Can you cat /proc/interrupts?
> Are you using the irq_balance code? If so, I think you'll only use
> 1 cpu to process all the interrupts from each gigabit card. Not that
> you have much choice, since Intel broke the P4's interrupt routing.
>

You got my attention with this statement. I've have Dual Xeon Prestonias on
an I860 chipset (IWill dp400). cat /proc/interrupts indeed shows CPU0 as
processing all IRQ's instead of sharing them with CPU1 on a 2.4.x kernel.

Is there a work around for this, or is this *really* a problem? Some say it
might be a problem depending on how many interrupts need to be processed per
second. Others imply that cpu0 catching the irq's might be a good thing.

I happen to have PIII's using VIA chipsets that dont have this issue with
proc/interrupts. This is very annonying, but I wonder if it is worth
worrying about.

Ron.