Controlling airtime fairness

Given the last time this was discussed is in November 2017; a couple of things have changed regarding the subsystem.

I'm generally confused and in that airtime_flags in /sys/kernel/debug/ieee80211/phy0/ath10k/airtime_flags or /sys/kernel/debug/ieee80211/phy1/ath9k/airtime_flags now displays 3 instead. What does a value of 3 mean? Should it be 7 to be enabled?

The devices I have are an Archer A7v5 with a QCA988X and 956X for ath10k and ath9k respectively.

I think this may answer your question?

Toke Høiland-Jørgensen•3 years ago

I assume you're talking about the flags, right? There are three of those, corresponding to the first three bits of the integer exposed in debugfs (and the 7 means they are all enabled by default). They are:

  • bit 1 (0x1): measure TX airtime
  • bit 2 (0x2): measure RX airtime
  • bit 3 (0x4): enable sparse station optimisation

They are not really tuning options, but rather debug parameters I added for testing


For anyone (in the future) wanting to find the command to check that airtime fairness is running in their system, this command should return an output (ath10k and ath9k):

cat /sys/kernel/debug/ieee80211/phy0/netdev\:wlan0/stations/*/airtime
cat /sys/kernel/debug/ieee80211/phy1/netdev\:wlan1/stations/*/airtime
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Is this relevant to openwrt 19?

It looks like there is better stuff happening in linux years newer than those links. I look forward to a release with all this good stuff.

In fact, I wanted to use these debug flags to test out the mailing list post you've shared.

I backported "Airtime Queue Limits" to backports-5.4-rc8 and ath10k-ct and it's working well on my Archer A7v5 running in a DumbAP config. I can feel the latency reduced quite a bit.

However, your quoted link is still in a preview stage and it ended up starving my device of memory when I backported it. It also ended up causing a lot of hostapd messages regarding mismatched/missed auth frames.

OpenWrt 19 uses backports-4.19 so it won't have these new features. Neither does master, until it gets updated with backports-5.5 or 5.6

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