High CPU interrupt load on intel I350T4 with igb on 8.3

[Barney Cordoba]

--- On Thu, 5/9/13, Eugene Grosbein <egrosbein at rdtc.ru> wrote:

> From: Eugene Grosbein <egrosbein at rdtc.ru>
> Subject: Re: High CPU interrupt load on intel I350T4 with igb on 8.3
> To: "Barney Cordoba" <barney_cordoba at yahoo.com>
> Cc: ""Clément Hermann (nodens)"" <nodens2099 at gmail.com>, freebsd-net at freebsd.org
> Date: Thursday, May 9, 2013, 12:30 PM
> On 09.05.2013 23:25, Barney Cordoba
> wrote:
> 
> >> Network device driver is not guilty here, that's
> just pf's
> >> contention
> >> running in igb's context.
> >>
> >> Eugene Grosbein
> > 
> > They're both at play. Single threadedness aggravates
> subsystems that 
> > have too many lock points.
> > 
> > It can also be "solved" with using 1 queue, because
> then you don't
> > have 4 queues going into a single thread.
> 
> Again, the problem is within pf(4)'s global lock, not in the
> igb(4).
> 

Again, you're wrong. It's not the bottleneck's fault; it's the fault of 
the multi-threaded code for only working properly when there are no
bottlenecks.

BC