[Cake] pie in dd-wrt

Sebastian Gottschall s.gottschall at newmedia-net.de
Thu Aug 22 05:17:36 EDT 2019

Am 21.08.2019 um 23:39 schrieb Toke Høiland-Jørgensen:
> 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.
as i said i already modified mac80211 in a way that it sets sane memory 
limits depending on the architecture. devices with just 32 mb ram run 
only stable with 256kb memory limit.
so i configured different defaults. but the point is still that for a 
standard user (lets say in openwrt) the current implementation is not 
good. somewhere in the openwrt community i was reading that such devices 
should not be used anymore for openwrt due the memory limitations. but 
thats no solution for me if it was working before the introduction of 
fq_codel in mac80211
> -Toke

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