Re: Weird NET_RX softirq behavior

Jisheng Zhang
2014-08-08T02:39:36Z

Hi Dmitry,

On Thu, 7 Aug 2014 07:18:13 -0700
Dmitry Popov <ixaphire@qrator.net> wrote:

> On Thu, 7 Aug 2014 17:10:50 +0800
> Jisheng Zhang <jszhang@marvell.com> wrote:
>
> > 2. only one netdev in the system: eth0.
>
> There should also be lo (loopback) at least.

Yep, I forget that ;)

>
> > 4. But NET_RX seems abnormal
> > ~ # cat /proc/softirqs
> > CPU0 CPU1 CPU2 CPU3
> > NET_RX: 445587 322 983 0
> >
> > I'm expecting NET_RX under CPU1, 2, 3 should be zero. Any suggestions
> > about this abnormal behavior?
>
> Do you have any loopback traffic? It could be handled by CPU1/2 explaining
> non-zero NET_RX counters.

Yes. lo only send and recive 7 packets so far, about 1400bytes. Seems small
comparing with the CPU1 and CPU2 NET_RX softirq numbers, right?

Any other possible case?

Thanks for your reply,
Jisheng