High interrupt rate on a PF box + performance

Jack Vogel jfvogel at gmail.com
Thu Jan 27 21:44:16 UTC 2011

On Thu, Jan 27, 2011 at 12:58 PM, Jeremy Chadwick
<freebsd at jdc.parodius.com>wrote:

> On Thu, Jan 27, 2011 at 09:38:22PM +0100, Damien Fleuriot wrote:
> > On 1/27/11 8:57 PM, Jeremy Chadwick wrote:
> >
> <...snipping out stuff...>
> > We're also considering moving to faster machines but I don't think that
> > will help much with our problem.
> >
> > I suppose additional CPU cores will be of no help at all, considering
> > the kernel is single threaded and runs on cpu0 only ?
> Kernel folks should be able to talk about this in detail, but my
> understanding is that the kernel itself supports multiple threads, but
> the question is whether or not the drivers or relevant "pieces" (e.g.
> igb(4) driver, pf, TCP stack, etc.) support SMP (multi-core/threading)
> or not.  I think this is referred to as something being "MPSAFE" or not.
The 8.X kernel is NOT single-threaded. Anything but. And the stack has
also been improved, I believe there are still bottlenecks but its far better
than the old days.

The igb driver in 8.2 creates up to 8 queues on the right hardware, they
are each auto-bound to a particular CPU.

The older version you are running had issues and hence multiqueue was
not enabled.  So, do upgrade once 8.2 is finalized :)



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