Speed degrading over time

Software SW help
1

I have a strange behaviour I’m trying to get rid of for some weeks, but cannot get over it.
I have a Turris Omnia with OS 6.1. ISP is a Fiber network with 100MBit downstream an 10MBit upstream.
When Turris starts up everything is fine. Then over some hours the downstream get slower and slower and the latency increases. Tried with SQM (bufferbloat) but that did not help.
Measured speed over time (with my homeassistant):

Speed
Speed1080×2340 184 KB

Now the real strange thing is, that only the LAN connected computers suffering from this. Tries speedtest-cli from the turris itself (via SSH) show full speed.
When I reboot the Turris everything is fine again for some hours.

Any ideas?

2

Maybe look at CPU or memory usage?

Some stuff I run takes up more of both over time causing similar issues.

3

Checked that already, but CPU is below 20% and about 300MB mem still free.
So I dont think this is an issue.

4

Maybe add netdata package and check monitoring if some bandwidth is in use. Are you using some extra services that might use the bandwodth?

5

Netdata does not show anything special. Dont forget the weird thing, that speedtest-cli gets the full speed from the Turris itself.
I think must be LAN related, but i cant figure out what is responsible

6

Found out, that Turris itself degraded like the LAN too, if SQM is enabled. Disabling it immetiately releases full speed, but only for the Turris, not for LAN.

7

Maybe post the output of tc -s qdisc from after a fresh restart and after a few days when the slow down was noticeable (both with SQM enabled)?

8

Following your hint did exactly that (tc): Noticed many dropped and overtimed pakets.
While playing around how to fix this, I enabled “Software flow offloading” in the Firewall config.
This seems to fix the issue, although I cannot say why.
Currenly working without SQM as the average usage is below 10% of the overall available bandwith.

Any more ideas on why this issue occurs in “normal” operation and why “Software flow offloading” fixes it?

9

Maybe post these here as well?

Not impossible that your router is overloaded with running SQM at the desired rates, software flow offloading will reduce the CPU load a bit and hence might help…

As long as you are happy all is well.