openwrt/package/kernel/mac80211/patches/subsys/333-mac80211-keep-recently-active-tx-queues-in-schedulin.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

119 lines
3.4 KiB
Diff

From: Felix Fietkau <nbd@nbd.name>
Date: Mon, 20 Jun 2022 20:52:50 +0200
Subject: [PATCH] mac80211: keep recently active tx queues in scheduling
list
This allows proper deficit accounting to ensure that they don't carry their
deficit until the next time they become active
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -83,6 +83,13 @@ extern const u8 ieee80211_ac_to_qos_mask
#define IEEE80211_MAX_NAN_INSTANCE_ID 255
+
+/*
+ * Keep a station's queues on the active list for deficit accounting purposes
+ * if it was active or queued during the last 100ms
+ */
+#define AIRTIME_ACTIVE_DURATION (HZ / 10)
+
struct ieee80211_bss {
u32 device_ts_beacon, device_ts_presp;
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -138,6 +138,7 @@ enum ieee80211_agg_stop_reason {
struct airtime_info {
u64 rx_airtime;
u64 tx_airtime;
+ u32 last_active;
s32 deficit;
atomic_t aql_tx_pending; /* Estimated airtime for frames pending */
u32 aql_limit_low;
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -3824,6 +3824,36 @@ static inline s32 ieee80211_sta_deficit(
return air_info->deficit - atomic_read(&air_info->aql_tx_pending);
}
+static void
+ieee80211_txq_set_active(struct txq_info *txqi)
+{
+ struct sta_info *sta;
+
+ if (!txqi->txq.sta)
+ return;
+
+ sta = container_of(txqi->txq.sta, struct sta_info, sta);
+ sta->airtime[txqi->txq.ac].last_active = (u32)jiffies;
+}
+
+static bool
+ieee80211_txq_keep_active(struct txq_info *txqi)
+{
+ struct sta_info *sta;
+ u32 diff;
+
+ if (!txqi->txq.sta)
+ return false;
+
+ sta = container_of(txqi->txq.sta, struct sta_info, sta);
+ if (ieee80211_sta_deficit(sta, txqi->txq.ac) >= 0)
+ return false;
+
+ diff = (u32)jiffies - sta->airtime[txqi->txq.ac].last_active;
+
+ return diff <= AIRTIME_ACTIVE_DURATION;
+}
+
struct ieee80211_txq *ieee80211_next_txq(struct ieee80211_hw *hw, u8 ac)
{
struct ieee80211_local *local = hw_to_local(hw);
@@ -3870,7 +3900,6 @@ struct ieee80211_txq *ieee80211_next_txq
}
}
-
if (txqi->schedule_round == local->schedule_round[ac])
goto out;
@@ -3890,12 +3919,13 @@ void __ieee80211_schedule_txq(struct iee
{
struct ieee80211_local *local = hw_to_local(hw);
struct txq_info *txqi = to_txq_info(txq);
+ bool has_queue;
spin_lock_bh(&local->active_txq_lock[txq->ac]);
+ has_queue = force || txq_has_queue(txq);
if (list_empty(&txqi->schedule_order) &&
- (force || !skb_queue_empty(&txqi->frags) ||
- txqi->tin.backlog_packets)) {
+ (has_queue || ieee80211_txq_keep_active(txqi))) {
/* If airtime accounting is active, always enqueue STAs at the
* head of the list to ensure that they only get moved to the
* back by the airtime DRR scheduler once they have a negative
@@ -3903,7 +3933,7 @@ void __ieee80211_schedule_txq(struct iee
* get immediately moved to the back of the list on the next
* call to ieee80211_next_txq().
*/
- if (txqi->txq.sta && local->airtime_flags &&
+ if (txqi->txq.sta && local->airtime_flags && has_queue &&
wiphy_ext_feature_isset(local->hw.wiphy,
NL80211_EXT_FEATURE_AIRTIME_FAIRNESS))
list_add(&txqi->schedule_order,
@@ -3911,6 +3941,8 @@ void __ieee80211_schedule_txq(struct iee
else
list_add_tail(&txqi->schedule_order,
&local->active_txqs[txq->ac]);
+ if (has_queue)
+ ieee80211_txq_set_active(txqi);
}
spin_unlock_bh(&local->active_txq_lock[txq->ac]);