On Tue, May 10, 2022 at 2:51 PM Rafał Miłecki [off-list ref] wrote:

On 6.05.2022 11:44, Arnd Bergmann wrote:

My router has a single swtich so I use two VLANs:
eth0.1 - LAN
eth0.2 - WAN
(VLAN traffic is routed to correct ports by switch). On top of that I
have "br-lan" bridge interface briding eth0.1 and wireless interfaces.

For all that time I had /sys/class/net/br-lan/queues/rx-0/rps_cpus set
to 3. So bridge traffic was randomly handled by CPU 0 or CPU 1.

So if I assign specific CPU core to each of two interfaces, e.g.:
echo 1 > /sys/class/net/eth0/queues/rx-0/rps_cpus
echo 2 > /sys/class/net/br-lan/queues/rx-0/rps_cpus
things get stable.

With above I get stable 419 Mb/s (CPUs load: 100% + 64%) on every iperf
session.

Ah, very nice! One part of the mystery is solved then I guess.

       Arnd