openwrt/package/kernel/mac80211/patches/subsys/332-mac80211-consider-aql_tx_pending-when-checking-airti.patch
Felix Fietkau 6d49a25804 mac80211: add airtime fairness improvements
This reverts the airtime scheduler back from the virtual-time based scheduler
to the deficit round robin scheduler implementation.
This reduces burstiness and improves fairness by improving interaction with AQL.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
2022-06-25 23:28:09 +02:00

49 lines
1.7 KiB
Diff

From: Felix Fietkau <nbd@nbd.name>
Date: Mon, 20 Jun 2022 14:59:09 +0200
Subject: [PATCH] mac80211: consider aql_tx_pending when checking airtime
deficit
When queueing packets for a station, deficit only gets added once the packets
have been transmitted, which could be much later. During that time, a lot of
temporary unfairness could happen, which could lead to bursty behavior.
Fix this by subtracting the aql_tx_pending when checking the deficit in tx
scheduling.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -3817,6 +3817,13 @@ out:
}
EXPORT_SYMBOL(ieee80211_tx_dequeue);
+static inline s32 ieee80211_sta_deficit(struct sta_info *sta, u8 ac)
+{
+ struct airtime_info *air_info = &sta->airtime[ac];
+
+ return air_info->deficit - atomic_read(&air_info->aql_tx_pending);
+}
+
struct ieee80211_txq *ieee80211_next_txq(struct ieee80211_hw *hw, u8 ac)
{
struct ieee80211_local *local = hw_to_local(hw);
@@ -3847,7 +3854,7 @@ struct ieee80211_txq *ieee80211_next_txq
struct sta_info *sta = container_of(txqi->txq.sta,
struct sta_info, sta);
bool aql_check = ieee80211_txq_airtime_check(hw, &txqi->txq);
- s32 deficit = sta->airtime[txqi->txq.ac].deficit;
+ s32 deficit = ieee80211_sta_deficit(sta, txqi->txq.ac);
if (aql_check)
found_eligible_txq = true;
@@ -3972,7 +3979,7 @@ bool ieee80211_txq_may_transmit(struct i
continue;
}
sta = container_of(iter->txq.sta, struct sta_info, sta);
- if (sta->airtime[ac].deficit < 0)
+ if (ieee80211_sta_deficit(sta, ac) < 0)
sta->airtime[ac].deficit += sta->airtime_weight;
list_move_tail(&iter->schedule_order, &local->active_txqs[ac]);
}