This qdisc aims to eliminate bufferbloat and as a side effect improves
latency during heavy network load. The most notable effect will be a
slightly more responsive ssh session during large downloads.
Systemd will autoselect fq_codel when it's available:
m8s:~ # ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 4096 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP8000> mtu 1500 qdisc fq_codel qlen 1000
link/ether 82:cd:fa:1b:03:1d brd ff:ff:ff:ff:ff:ff
inet 172.20.0.166/24 brd 172.20.0.255 scope global eth0
valid_lft forever preferred_lft forever
3: wlan0: <NO-CARRIER,BROADCAST,MULTICAST,UP,LOWER_UP8000> mtu 1500 qdisc fq_codel qlen 1000
link/ether 44:2c:05:43:8c:eb brd ff:ff:ff:ff:ff:ff
inet6 fe80::462c:5ff:fe43:8ceb/64 scope link
valid_lft forever preferred_lft forever
On the S905X 100Mbit link it shows no negative effects:
m8s:~ # curl http://beast.local/koen/largefile.mkv --http1.1 > /dev/null
% Total % Received % Xferd Average Speed Time Time
% Time
% Current
Dload Upload Total Spent Left Speed
7 14.9G 7 1105M 0 0 11.1M 0 0:22:50 0:01:38 0:21:12 11.2M
See https://en.wikipedia.org/wiki/CoDel for more information on CODEL
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
Many WeTek Core users have been experiencing major UI lag issues when
using the "ondemand" governor. If left inactive for a period of time,
the UI becomes extremely sluggish and a reboot is required.
Users did not experience this issue with LE 7. The switch from the
"performance" to "interactive" governor was made in revision 8610fb3270
("projects/WeTek_Core: Use interactive CPU scaling governor by
default"). Users then started experiencing the UI issues, and revision
c908c1f453 ("projects/WeTek_Core: Switch to ondemand CPU scaling
governor") attempted to address the problem. Unfortunately, this did
not appear to resolve the issue.
After switching to "hotplug", users could not replicate the UI lag
issues anymore.
The interactive CPU scaling governor for some reason causes a significant slowdown after some time of inactivity.
WeTek Core becomes very sluggish and almost unusable until a reboot.
Switching to ondemand governor seems fixes the issue.
