[SOLVED] SQM Dangerous configuration


I am reading -> https://lede-project.org/docs/howto/sqm#sqmqueue_discipline_tab

and it says "Latency target for ingress: The codel algorithm specifies a target, expressed in msec. Use “auto” for a calculated compensation for slow links (less than 4 mbps). Leave it empty for the default."

But in LUCI it says:
Latency target for ingress, e.g 5ms [units: s, ms, or us]; leave empty for automatic selection, put in the word default for the qdisc's default.

So in which case do I leave it empty?
I have 20Mbit/s down 2Mbit/s up bandwidth, how should I configure itarget and etarget?

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Leave it empty and post the output of "tc -s qdisc" here, please. IIRC the real GUI defsaults were changed and the howto has not been updated. If you can confirm this we can fix the howto...

The current code intends to interpret an empty field as the directive to auto-adjust the target parameters, Note, as far as I can tell, cake does this adjustments by itself independent of the setting, so this will only affect fq_codel and pie (which I believe is not part of lede atm). But please test, so that we can make sure things work as intended before modifying the howto

Best Regards

Thank you Sebastian,

here you go (itarget and etarget empty) -> https://pastebin.com/t9DCfyhi

(itarget default and etarget auto) -> https://pastebin.com/pqa4QJgW

Thanks a lot,

as I expected, cake does not care at all either way, it simply adjusts the target to allow at least one full MTU packet in the queue. I guess I need to repeat the "experiment" with plain simple.qos/fq_codel to see what works, but from looking at the code the howto seems outdated...

Best Regards

Okay, finally got to test it, luci-app-sqm was correct and the howto a bit dated; but now the howto is fixed as well. Many thanks for noticing and testing!

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