Maximum NIC interrupts

Michael DeMan michael at
Wed Dec 26 02:41:51 PST 2007


I think this is a really good question.

I'm curious since we use a lot of stripped-down FreeBSD for modest  
performance routers.

We typically enabling our interfaces with POLLING not so much for  
performance (it seems to be a negligible improvement nowadays) but so  
that we know that our OSPF/BGP/SSH processes are always responsive.

I'd be curious if anybody could get back on this.  I've never even  
considered things from the perspective of how many interrupts a NIC  
could generate other than that they could always generate too many.

- mike

On Dec 26, 2007, at 2:12 AM, Jordi Espasa Clofent wrote:

> OK, I'll try to explain in another way.
> While I've done network performance test I've monitored the IRQ  
> rate, and, for example, it's a 7000/8000 interrupts per second in  
> every NIC (I use 2 NICs in a bridge). The question is
> ¿how can I know if this irq rate is too high or not? ¿how can I  
> know if I'm closer to device limits, or kernel limits?
> I want to say that I'm don't know if 8000 irq per second means a  
> high IRQ use or a lower user.
> I hope I've explained better at this time.
> -- 
> Thanks,
> Jordi Espasa Clofent
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