Reason for messages “HTB: quantum of class 10001 is big. Consider r2q change”

Once on the access server, Ubuntu Server 16.04 and Accel-ppp noticed the following messages in the /var/log/kern.log file:

kernel: [365970.550498] HTB: quantum of class 10001 is big. Consider r2q change.
kernel: [365970.550547] HTB: quantum of class 10A49 is big. Consider r2q change.
kernel: [365979.545580] HTB: quantum of class 10001 is big. Consider r2q change.
kernel: [365979.545621] HTB: quantum of class 10BD6 is big. Consider r2q change.
kernel: [365995.601973] HTB: quantum of class 10001 is big. Consider r2q change.
kernel: [365995.602031] HTB: quantum of class 11705 is big. Consider r2q change.

First I tried to track which interfaces are being raised at this moment:

tail -f /var/log/kern.log | grep "quantum of class 10001 is big"
tail -f /var/log/accel-ppp/accel-ppp.log | grep "create interface"

But as it turned out, in the configuration of /etc/accel-ppp.conf, in the shaper section, quantum was not specified, and if it is not specified, it is calculated.
So I opened the Accel-ppp configuration file:

sudo nano /etc/accel-ppp.conf

And pointed it out:

[shaper]
quantum=1500
#moderate-quantum=1

Also changed the up-limiter from “htb” to “police” for better performance, and also to get the speed cut off correctly with a large number of sessions (at 3000+ ipoe sessions with htb problems started, the sending rate fell to 1 MB/sec):

#up-limiter=htb
up-limiter=police

To apply the change for new sessions without terminating the active ones, we will force Accel-ppp to re-read the configuration file:

telnet 127.0.0.1 2000
reload

Or we will reload Accel-ppp, but all sessions will be terminated:

sudo /etc/init.d/accel-ppp restart

After that, the error disappeared.

See also my article – Accel-ppp installation

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