From: Felix Fietkau <nbd@nbd.name>
Date: Sun, 26 Jun 2022 11:43:25 +0200
Subject: [PATCH] mac80211: increase quantum for airtime scheduler

Given the typical AQL budget and queue length, a quantum of 256 with the
default station weight often requires iterating over all queues frequently,
until one of them becomes eligible.
Improve performance by using 8 times station weight as scheduler quantum

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---

--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -103,6 +103,8 @@ ieee80211_sta_keep_active(struct sta_inf
 	return time_before_eq(jiffies, sta->airtime[ac].last_active + HZ / 10);
 }
 
+#define AIRTIME_QUANTUM_SHIFT	3
+
 struct ieee80211_bss {
 	u32 device_ts_beacon, device_ts_presp;
 
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -4081,7 +4081,7 @@ struct ieee80211_txq *ieee80211_next_txq
 
 		if (deficit < 0)
 			sta->airtime[txqi->txq.ac].deficit +=
-				sta->airtime_weight;
+				sta->airtime_weight << AIRTIME_QUANTUM_SHIFT;
 
 		if (deficit < 0 || !aql_check) {
 			list_move_tail(&txqi->schedule_order,
@@ -4224,7 +4224,8 @@ bool ieee80211_txq_may_transmit(struct i
 		}
 		sta = container_of(iter->txq.sta, struct sta_info, sta);
 		if (ieee80211_sta_deficit(sta, ac) < 0)
-			sta->airtime[ac].deficit += sta->airtime_weight;
+			sta->airtime[ac].deficit += sta->airtime_weight <<
+						    AIRTIME_QUANTUM_SHIFT;
 		list_move_tail(&iter->schedule_order, &local->active_txqs[ac]);
 	}
 
@@ -4232,7 +4233,7 @@ bool ieee80211_txq_may_transmit(struct i
 	if (sta->airtime[ac].deficit >= 0)
 		goto out;
 
-	sta->airtime[ac].deficit += sta->airtime_weight;
+	sta->airtime[ac].deficit += sta->airtime_weight << AIRTIME_QUANTUM_SHIFT;
 	list_move_tail(&txqi->schedule_order, &local->active_txqs[ac]);
 	spin_unlock_bh(&local->active_txq_lock[ac]);