[Cerowrt-devel] Somebody want to hit me with a clue-by-four regarding fq_codel?

[Cerowrt-devel] Somebody want to hit me with a clue-by-four regarding fq_codel?

[Valdis Klētnieks]

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OK, what am I missing here?  Laptop, linux-next kernel from last week.
And we'll skip the food fight about whether fq_codel makes sense for
end nodes - this is a different issue..

I've set fq_codel as the default qdisc

[/proc/sys/net] cat core/default_qdisc
fq_codel

but it's not being used?

[/proc/sys/net] tc -s qdisc show
qdisc noqueue 0: dev lo root refcnt 2
 Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
 backlog 0b 0p requeues 0
qdisc pfifo_fast 0: dev eth0 root refcnt 2 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
 Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
 backlog 0b 0p requeues 0
qdisc noqueue 0: dev wlan0 root refcnt 2
 Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
 backlog 0b 0p requeues 0

But if I give it a kick in the head...

[/proc/sys/net] tc qdisc add dev wlan0 root fq_codel
[/proc/sys/net] tc -s qdisc show dev wlan0
qdisc fq_codel 8001: root refcnt 2 limit 10240p flows 1024 quantum 1514 target 5ms interval 100ms memory_limit 32Mb ecn drop_batch 64
 Sent 812 bytes 12 pkt (dropped 0, overlimits 0 requeues 0)
 backlog 0b 0p requeues 0
  maxpacket 0 drop_overlimit 0 new_flow_count 0 ecn_mark 0
  new_flows_len 0 old_flows_len 0

(Admittedly, my first guess is "systemd is probably being its fascist self
and setting it to what *it* thinks things should be like"... :)




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Re: [Cerowrt-devel] Somebody want to hit me with a clue-by-four regarding fq_codel?

[Dave Taht]

wlan0 is using the native fq_codel implementation if you see a aqm
field in the sysfs, and noqueue for all other wifi devices as the
drivers themselves were so overbuffered there was no point in
pfifo_fast for them.

systemd is supposed to set fq_codel for you in /etc/sysctl.conf or
elsewhere, for your ethernet.

On Sat, Jan 2, 2021 at 10:21 AM Valdis Klētnieks
<valdis.kletnieks@vt.edu> wrote:
>
> OK, what am I missing here?  Laptop, linux-next kernel from last week.
> And we'll skip the food fight about whether fq_codel makes sense for
> end nodes - this is a different issue..
>
> I've set fq_codel as the default qdisc
>
> [/proc/sys/net] cat core/default_qdisc
> fq_codel
>
> but it's not being used?
>
> [/proc/sys/net] tc -s qdisc show
> qdisc noqueue 0: dev lo root refcnt 2
>  Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
>  backlog 0b 0p requeues 0
> qdisc pfifo_fast 0: dev eth0 root refcnt 2 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
>  Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
>  backlog 0b 0p requeues 0
> qdisc noqueue 0: dev wlan0 root refcnt 2
>  Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
>  backlog 0b 0p requeues 0
>
> But if I give it a kick in the head...
>
> [/proc/sys/net] tc qdisc add dev wlan0 root fq_codel
> [/proc/sys/net] tc -s qdisc show dev wlan0
> qdisc fq_codel 8001: root refcnt 2 limit 10240p flows 1024 quantum 1514 target 5ms interval 100ms memory_limit 32Mb ecn drop_batch 64
>  Sent 812 bytes 12 pkt (dropped 0, overlimits 0 requeues 0)
>  backlog 0b 0p requeues 0
>   maxpacket 0 drop_overlimit 0 new_flow_count 0 ecn_mark 0
>   new_flows_len 0 old_flows_len 0
>
> (Admittedly, my first guess is "systemd is probably being its fascist self
> and setting it to what *it* thinks things should be like"... :)
>
>
>
> _______________________________________________
> Cerowrt-devel mailing list
> Cerowrt-devel@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/cerowrt-devel



-- 
"For a successful technology, reality must take precedence over public
relations, for Mother Nature cannot be fooled" - Richard Feynman

dave@taht.net <Dave Täht> CTO, TekLibre, LLC Tel: 1-831-435-0729

Re: [Cerowrt-devel] Somebody want to hit me with a clue-by-four regarding fq_codel?

[Valdis Klētnieks]

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On Sat, 02 Jan 2021 10:26:44 -0800, Dave Taht said:
> systemd is supposed to set fq_codel for you in /etc/sysctl.conf or
> elsewhere, for your ethernet.

"D'Oh!" - H. Simpson.

Turns out it went pear-shaped before systemd got its grubby little paws on it.

% zgrep -i fq_codel /proc/config.gz 
CONFIG_NET_SCH_FQ_CODEL=m
CONFIG_DEFAULT_FQ_CODEL=y
CONFIG_DEFAULT_NET_SCH="fq_codel"

No joy can come from this.  :)


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