Too much interrupts on ixgbe

[Jack Vogel]

On Tue, Oct 25, 2011 at 12:22 AM, Sergey Saley <sergeysaley at gmail.com>wrote:

>
> Ryan Stone-2 wrote:
> >
> > On Mon, Oct 24, 2011 at 3:51 PM, Sergey Saley &lt;sergeysaley@&gt;
> wrote:
> >> MPD5, netgraph, pppoe.Types of traffic - any (customer traffic).
> >> Bying this card I counted on a 3-4G traffic at 3-4K pppoe sessions.
> >> It turned to 600-700Mbit/s, about 50K pps at 700-800 pppoe sessions.
> >
> > PPPoE is your problem.  The Intel cards can't load-balance PPPoE
> > traffic, so everything goes to one queue.  It may be possible to write
> > a netgraph module to load-balance the traffic across your CPUs.
> >
>
> OK, thank You for explanation.
> And what about the large number of interrupts?
> As for me, it's too much...
> irq256: ix0:que 0              240536944       6132
> irq257: ix0:que 1               89090444       2271
> irq258: ix0:que 2               93222085       2376
> irq259: ix0:que 3               89435179       2280
> irq260: ix0:link                       1          0
> irq261: ix1:que 0              269468769       6870
> irq262: ix1:que 1                 110974          2
> irq263: ix1:que 2                 434214         11
> irq264: ix1:que 3                 112281          2
> irq265: ix1:link                       1          0
>
>
How do you decide its 'too much' ?  It may be that with your traffic you end
up
not being able to use offloads, just thinking. Its not like the hardware
just "makes
it up", it interrupts on the last descriptor of a packet which has the RS
bit set.
With TSO you will get larger chunks of data and thus less interrupts but
your
traffic probably doesn't qualify for it.

Jack