[Cake] pie in dd-wrt

Toke Høiland-Jørgensen toke at redhat.com
Wed Aug 21 17:39:50 EDT 2019

Sebastian Gottschall <s.gottschall at newmedia-net.de> writes:

> Am 21.08.2019 um 18:21 schrieb Sebastian Moeller:
>> On August 21, 2019 6:12:03 PM GMT+02:00, Sebastian Gottschall <s.gottschall at newmedia-net.de> wrote:
>>> thats rather old. i rewrote all the qos code in the last 4 or 5 days.
>>> so
>>> things might be changed. next phase is bringing all the link level
>>> detail configuration stuff into the gui which will be done
>>> tomorrow or at least still within this week.
>>> i also added now cake to some smaller low budged routers with limited
>>> resources, so see how it runs. i had bad experiences with fq_codel in
>>> the past due some high memory usage.
>>> especially since its hard coded somewhat into the wireless ath9k
>>> driver.
>>> so i already modded it for more efficient handling. 4 mb max per queue
>>> is simply too much for  a 32 mb ram based router.
>> This is why I'm sqm we reduced the queued packet maximum m to around 1000, and also why cake has an explicit memlimit keyword.
> yeah but does this help if fq_codel is hardcoded into mac80211? fq_codel 
> has a memlimit  keyword too btw. its fixed to 4MB. i reduced it to 256kb 
> on low memory architectures. no other way to get around OOM problems
> mac80211  does always make use of fq_codel. it has a own build in 
> implementation

The mac80211 implementation also has a memlimit parameter. You can set
it through debugfs - 2MB would be:

echo 2097152 > /sys/kernel/debug/ieee80211/phy0/aqm

or through iw:

iw phy phy0 set txq memory_limit 2097152

The nl80211 attribute is called NL80211_ATTR_TXQ_MEMORY_LIMIT.


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