Re: tc - mirred ingress not supported at the moment

On Wed, Aug 14, 2019 at 2:02 AM Martin Olsson
[off-list ref] wrote:

Hi Cong!

Ah sorry.
Already implemented. Great!

Hmmm. Then why don't the manual at https://www.linux.org/docs/man8/tc-mirred.html to reflect the changes?
That was the place I checked to see if ingress was still not implemented.
In the commit you point at, the sentence "Currently only egress is implemented" has been removed.

This means that website is out-of-date, not sync'ed with latest man pages.

Question:
Is there any form of performance penalty if I send the mirrored traffic to the ingress queue of the destination interface rather than to the egress queue?
I mean, in the kernel there is the possibility to perform far more actions on the ingress queue than on the egress, but if I leave both queues at their defaults, will mirrored packets to ingress use more CPU cycles than to the egress destination, or are they more or less identical?

Hard to say without measurement. There is no queue on ingress
side, by the way, so it could be faster than egress, regarding to
lock contentions on queues.

Question 2:
Given the commit https://git.kernel.org/pub/scm/network/iproute2/iproute2.git/commit/?id=5eca0a3701223619a513c7209f7d9335ca1b4cfa, how can I see in what kernel version it was added?

The kernel commit is:

commit 53592b3640019f2834701093e38272fdfd367ad8
Author: Shmulik Ladkani [off-list ref]
Date:   Thu Oct 13 09:06:44 2016 +0300

    net/sched: act_mirred: Implement ingress actions

which is merged in 4.10.

Thanks.