mac80211: increase airtime scheduler quantum
improves performance by requiring fewer iterations over tx queues Signed-off-by: Felix Fietkau <nbd@nbd.name>
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		| @@ -0,0 +1,53 @@ | |||||||
|  | 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 | ||||||
|  | @@ -90,6 +90,8 @@ extern const u8 ieee80211_ac_to_qos_mask | ||||||
|  |   */ | ||||||
|  |  #define AIRTIME_ACTIVE_DURATION (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 | ||||||
|  | @@ -3894,7 +3894,7 @@ 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, | ||||||
|  | @@ -4037,7 +4037,8 @@ 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]); | ||||||
|  |  	} | ||||||
|  |   | ||||||
|  | @@ -4045,7 +4046,7 @@ 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]); | ||||||
|  |   | ||||||
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