Added Latency When Using FQ Codel?

[tman222]

Hi all,

I have noticed when using Limiters w/fq_codel that latency is higher when I perform a simple ping test between two separate subnets. Consider the following setup:

Subnet A (192.168.1.0/24) with Limiter/fq_codel enabled on outbound LAN firewall rule.
Subnet B (192.168.2.0/24) with Limiter/fq_codel enabled on outbound LAN firewall rule

Subnet A is allowed to pass traffic to Subnet B.

When I ping subnet B (e.g. let's say the gateway at 192.168.2.1) from a machine on subnet A I see that latency is about 100 - 200 microseconds (0.1 - 0.2 milliseconds) higher compared to if I remove the Limiters/fq_codel from subnet A's outbound LAN firewall rule completely.

I'm curious if you guys think this should be the expected behavior when using Limiters/fq_codel? I realize there is now Fair Queuing (FQ) and AQM (Codel) when applying the queues to the outbound LAN rule, but 0.1 - 0.2ms seems high to me, even when considering that some delay is expected due to additional processing required.

What do you guys think? Thanks in advance.

[tman222]

@dtaht and/or @Rasool - do you guys have any ideas on this? Thanks in advance for your help.