2022-06-25 21:27:25

by Felix Fietkau

Subject: [PATCH 7/7] mac80211: only accumulate airtime deficit for active clients

When a client does not generate any local tx activity, accumulating airtime
deficit for the round-robin scheduler can be harmful. If this goes on for too
long, the deficit could grow quite large, which might cause unreasonable
initial latency once the client becomes active

Signed-off-by: Felix Fietkau <[email protected]>
---
net/mac80211/sta_info.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 28ab55a072c6..c9852f71e8e1 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -2046,6 +2046,7 @@ void ieee80211_sta_register_airtime(struct ieee80211_sta *pubsta, u8 tid,
struct ieee80211_local *local = sta->sdata->local;
u8 ac = ieee80211_ac_from_tid(tid);
u32 airtime = 0;
+ u32 diff;

if (sta->local->airtime_flags & AIRTIME_USE_TX)
airtime += tx_airtime;
@@ -2055,7 +2056,11 @@ void ieee80211_sta_register_airtime(struct ieee80211_sta *pubsta, u8 tid,
spin_lock_bh(&local->active_txq_lock[ac]);
sta->airtime[ac].tx_airtime += tx_airtime;
sta->airtime[ac].rx_airtime += rx_airtime;
- sta->airtime[ac].deficit -= airtime;
+
+ diff = (u32)jiffies - sta->airtime[ac].last_active;
+ if (diff <= AIRTIME_ACTIVE_DURATION)
+ sta->airtime[ac].deficit -= airtime;
+
spin_unlock_bh(&local->active_txq_lock[ac]);
}
EXPORT_SYMBOL(ieee80211_sta_register_airtime);
--
2.36.1

2022-06-27 15:07:12

by Toke Høiland-Jørgensen

Subject: Re: [PATCH 7/7] mac80211: only accumulate airtime deficit for active clients

Felix Fietkau <[email protected]> writes:

> When a client does not generate any local tx activity, accumulating airtime
> deficit for the round-robin scheduler can be harmful. If this goes on for too
> long, the deficit could grow quite large, which might cause unreasonable
> initial latency once the client becomes active
>
> Signed-off-by: Felix Fietkau <[email protected]>

Acked-by: Toke Høiland-Jørgensen <[email protected]>