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Commit message (Expand)AuthorAgeFilesLines
* broadcom-wl: detect all radios when generating config, do wireless setup per-...Jo-Philipp Wich2010-01-221-13/+19
* broadcom-wl: properly detach nas by using start-stop-daemon to launch itJo-Philipp Wich2010-01-211-0/+1
* broadcom-wl: implement wepauth in wlc and support it in broadcom.sh, allows s...Jo-Philipp Wich2010-01-212-1/+12
* broadcom-wl: add rts/frag threshold settings (patch from #4769)Felix Fietkau2009-12-091-0/+4
* implement doth (802.11h) and wmm (802.11e) options for broadcom as well; upda...Jo-Philipp Wich2009-09-221-3/+9
* broadcom-wl: add "assoclist" command to wlcJo-Philipp Wich2009-08-062-2/+9
* broadcom-wl: fix broadcom (2.4) wireless sta (only) mode, adjust release numberNicolas Thill2009-06-012-2/+2
* delay the starting of nas4wds, seems like 5 seconds works in every case: none...Florian Fainelli2009-05-282-2/+2
* allow sta mode to work with psk+aes (#4687)Florian Fainelli2009-05-222-1/+2
* broadcom-wl: add nvram stub to fix nas compile after the switch to unvramFelix Fietkau2009-04-272-3/+25
* get rid of $Id$ - it has never helped us and it has broken too many patches ;)Felix Fietkau2009-04-1739-39/+0
* sync macs with vif bssids in broadcom.sh, fixes multi-ssid with wpaJo-Philipp Wich2009-03-241-1/+1
* replace some -I & -L flags with $(TARGET_CPPFLAGS) & $(TARGET_LDFLAGS) when a...Nicolas Thill2009-02-241-1/+1
* broadcom-wl: move txpower back to wifi-device section, but remain backwards c...Andy Boyett2009-01-312-6/+11
* make broadcom-wl robust against implicit kernel config changes (e.g. netfilte...Felix Fietkau2009-01-074-5/+77
* remove mac address handling, now handled by /lib/network/config.shJo-Philipp Wich2008-11-171-1/+1
* move the txpower option to wifi-iface to mimic madwifi configurationJo-Philipp Wich2008-11-161-2/+3
* package/broadcom-wl: - use [tr]xantenna instead of [tr]xant to unify config -...Jo-Philipp Wich2008-11-161-4/+7
* Allow setting the MAC address on a broadcom device (#1512)Florian Fainelli2008-11-091-0/+2
* broadcom-wl: only use mssid if necessary (fixes spurious error messages on ol...Felix Fietkau2008-09-281-1/+7
* add vif selection fix for the broadcom-wl wifi script (thx, sn9)Felix Fietkau2008-08-161-0/+1
* Make sure we will have lower case MAC addresses when doing WDSFlorian Fainelli2008-08-091-1/+4
* Support encrypted WDS connections (#2463)Florian Fainelli2008-08-091-1/+14
* install libshared into the staging dir (required by wrt-radauth)Felix Fietkau2008-08-051-0/+5
* Default to port 1812 for radius authentication when doing 802.1xFlorian Fainelli2008-07-211-1/+1
* Support for setting monitor mode (#1306)Florian Fainelli2008-07-151-7/+27
* add timer fix by mmp from http://forum.openwrt.org/viewtopic.php?id=14841Felix Fietkau2008-04-071-0/+53
* upgrade to broadcom-wl 4.150.10.5.2Felix Fietkau2008-04-071-4/+10
* add frameburst closes #1759Travis Kemen2008-03-291-0/+2
* upgrade broadcom-wl, fixes wpa2 issues. remove compat-ldso, not necessary any...Felix Fietkau2008-01-164-307/+2
* fix multi-essid setting for broadcom-wlFelix Fietkau2008-01-161-1/+1
* revert [10201] - the broadcom-wl md5sum was correct, the upload on mirror2 ho...Felix Fietkau2008-01-151-1/+1
* broadcom-wl md5sum fixed, thanks ix.Andy Boyett2008-01-151-1/+1
* update brcm-2.4 to 2.4.35.4, integrate new broadcom system code, update broad...Felix Fietkau2008-01-0631-2617/+8017
* Set country before channel (#2958)Florian Fainelli2008-01-041-1/+1
* Force broadcom-compat-ldso to be 2.4 only (#2963)Florian Fainelli2008-01-031-0/+1
* enable broadcom-wl compat hacksFelix Fietkau2008-01-031-7/+7
* Fix macfiltering for broadcom devices (#2822)Florian Fainelli2007-12-191-13/+12
* add missing dependencyFelix Fietkau2007-12-031-1/+1
* comment out dependencies that are not supposed to be used yet (#2723)Felix Fietkau2007-11-171-2/+3
* wlcompat: show wet mode as Managed mode as well to avoid confusionFelix Fietkau2007-11-101-13/+8
* move wlcompat to the broadcom-wl packageFelix Fietkau2007-11-1024-10/+1111
* revert abi changes in uClibc - on hold for 7.11, will be added again with the...Felix Fietkau2007-11-091-5/+5
* disable crt_fini compatibility in uClibc, compile custom ld-uClibc for broadc...Felix Fietkau2007-11-094-1/+304
* Revert [9176] now that we have network config handling stp [9343]Florian Fainelli2007-10-181-3/+0
* Turn on stp for br-lan only when doing wds (#2476)Florian Fainelli2007-10-071-0/+2
* Fix macfiltering options (#2397)Florian Fainelli2007-09-161-4/+4
* Add macfiltering to broadcom-wlFlorian Fainelli2007-09-121-2/+17
* major target cleanup. it is now possible to have subtargets that can override...Felix Fietkau2007-09-081-2/+2
* move package description to a separate definition, remove it when DESCRIPTION...Nicolas Thill2007-09-071-20/+34
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From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@toke.dk>
Date: Mon, 5 Dec 2016 13:27:37 +0200
Subject: [PATCH] ath9k: Introduce airtime fairness scheduling between stations
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This reworks the ath9k driver to schedule transmissions to connected
stations in a way that enforces airtime fairness between them. It
accomplishes this by measuring the time spent transmitting to or
receiving from a station at TX and RX completion, and accounting this to
a per-station, per-QoS level airtime deficit. Then, an FQ-CoDel based
deficit scheduler is employed at packet dequeue time, to control which
station gets the next transmission opportunity.

Airtime fairness can significantly improve the efficiency of the network
when station rates vary. The following throughput values are from a
simple three-station test scenario, where two stations operate at the
highest HT20 rate, and one station at the lowest, and the scheduler is
employed at the access point:

                  Before   /   After
Fast station 1:    19.17   /   25.09 Mbps
Fast station 2:    19.83   /   25.21 Mbps
Slow station:       2.58   /    1.77 Mbps
Total:             41.58   /   52.07 Mbps

The benefit of airtime fairness goes up the more stations are present.
In a 30-station test with one station artificially limited to 1 Mbps,
we have seen aggregate throughput go from 2.14 to 17.76 Mbps.

Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
---

--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -112,6 +112,8 @@ int ath_descdma_setup(struct ath_softc *
 #define ATH_TXFIFO_DEPTH           8
 #define ATH_TX_ERROR               0x01
 
+#define ATH_AIRTIME_QUANTUM        300 /* usec */
+
 /* Stop tx traffic 1ms before the GO goes away */
 #define ATH_P2P_PS_STOP_TIME       1000
 
@@ -247,6 +249,9 @@ struct ath_atx_tid {
 	bool has_queued;
 };
 
+void __ath_tx_queue_tid(struct ath_softc *sc, struct ath_atx_tid *tid);
+void ath_tx_queue_tid(struct ath_softc *sc, struct ath_atx_tid *tid);
+
 struct ath_node {
 	struct ath_softc *sc;
 	struct ieee80211_sta *sta; /* station struct we're part of */
@@ -258,9 +263,12 @@ struct ath_node {
 
 	bool sleeping;
 	bool no_ps_filter;
+	s64 airtime_deficit[IEEE80211_NUM_ACS];
+	u32 airtime_rx_start;
 
 #ifdef CPTCFG_ATH9K_STATION_STATISTICS
 	struct ath_rx_rate_stats rx_rate_stats;
+	struct ath_airtime_stats airtime_stats;
 #endif
 	u8 key_idx[4];
 
@@ -317,10 +325,16 @@ struct ath_rx {
 /* Channel Context */
 /*******************/
 
+struct ath_acq {
+	struct list_head acq_new;
+	struct list_head acq_old;
+	spinlock_t lock;
+};
+
 struct ath_chanctx {
 	struct cfg80211_chan_def chandef;
 	struct list_head vifs;
-	struct list_head acq[IEEE80211_NUM_ACS];
+	struct ath_acq acq[IEEE80211_NUM_ACS];
 	int hw_queue_base;
 
 	/* do not dereference, use for comparison only */
@@ -575,6 +589,8 @@ void ath_txq_schedule_all(struct ath_sof
 int ath_tx_init(struct ath_softc *sc, int nbufs);
 int ath_txq_update(struct ath_softc *sc, int qnum,
 		   struct ath9k_tx_queue_info *q);
+u32 ath_pkt_duration(struct ath_softc *sc, u8 rix, int pktlen,
+		     int width, int half_gi, bool shortPreamble);
 void ath_update_max_aggr_framelen(struct ath_softc *sc, int queue, int txop);
 void ath_assign_seq(struct ath_common *common, struct sk_buff *skb);
 int ath_tx_start(struct ieee80211_hw *hw, struct sk_buff *skb,
@@ -963,6 +979,11 @@ void ath_ant_comb_scan(struct ath_softc
 
 #define ATH9K_NUM_CHANCTX  2 /* supports 2 operating channels */
 
+#define AIRTIME_USE_TX		BIT(0)
+#define AIRTIME_USE_RX		BIT(1)
+#define AIRTIME_USE_NEW_QUEUES	BIT(2)
+#define AIRTIME_ACTIVE(flags) (!!(flags & (AIRTIME_USE_TX|AIRTIME_USE_RX)))
+
 struct ath_softc {
 	struct ieee80211_hw *hw;
 	struct device *dev;
@@ -1005,6 +1026,8 @@ struct ath_softc {
 	short nbcnvifs;
 	unsigned long ps_usecount;
 
+	u16 airtime_flags; /* AIRTIME_* */
+
 	struct ath_rx rx;
 	struct ath_tx tx;
 	struct ath_beacon beacon;
--- a/drivers/net/wireless/ath/ath9k/channel.c
+++ b/drivers/net/wireless/ath/ath9k/channel.c
@@ -118,8 +118,11 @@ void ath_chanctx_init(struct ath_softc *
 		INIT_LIST_HEAD(&ctx->vifs);
 		ctx->txpower = ATH_TXPOWER_MAX;
 		ctx->flush_timeout = HZ / 5; /* 200ms */
-		for (j = 0; j < ARRAY_SIZE(ctx->acq); j++)
-			INIT_LIST_HEAD(&ctx->acq[j]);
+		for (j = 0; j < ARRAY_SIZE(ctx->acq); j++) {
+			INIT_LIST_HEAD(&ctx->acq[j].acq_new);
+			INIT_LIST_HEAD(&ctx->acq[j].acq_old);
+			spin_lock_init(&ctx->acq[j].lock);
+		}
 	}
 }
 
@@ -1345,8 +1348,11 @@ void ath9k_offchannel_init(struct ath_so
 	ctx->txpower = ATH_TXPOWER_MAX;
 	cfg80211_chandef_create(&ctx->chandef, chan, NL80211_CHAN_HT20);
 
-	for (i = 0; i < ARRAY_SIZE(ctx->acq); i++)
-		INIT_LIST_HEAD(&ctx->acq[i]);
+	for (i = 0; i < ARRAY_SIZE(ctx->acq); i++) {
+		INIT_LIST_HEAD(&ctx->acq[i].acq_new);
+		INIT_LIST_HEAD(&ctx->acq[i].acq_old);
+		spin_lock_init(&ctx->acq[i].lock);
+	}
 
 	sc->offchannel.chan.offchannel = true;
 }
--- a/drivers/net/wireless/ath/ath9k/debug.c
+++ b/drivers/net/wireless/ath/ath9k/debug.c
@@ -1399,5 +1399,8 @@ int ath9k_init_debug(struct ath_hw *ah)
 	debugfs_create_file("tpc", S_IRUSR | S_IWUSR,
 			    sc->debug.debugfs_phy, sc, &fops_tpc);
 
+	debugfs_create_u16("airtime_flags", S_IRUSR | S_IWUSR,
+			   sc->debug.debugfs_phy, &sc->airtime_flags);
+
 	return 0;
 }
--- a/drivers/net/wireless/ath/ath9k/debug.h
+++ b/drivers/net/wireless/ath/ath9k/debug.h
@@ -221,6 +221,11 @@ struct ath_rx_rate_stats {
 	} cck_stats[4];
 };
 
+struct ath_airtime_stats {
+	u32 rx_airtime;
+	u32 tx_airtime;
+};
+
 #define ANT_MAIN 0
 #define ANT_ALT  1
 
@@ -314,12 +319,20 @@ ath9k_debug_sync_cause(struct ath_softc
 void ath_debug_rate_stats(struct ath_softc *sc,
 			  struct ath_rx_status *rs,
 			  struct sk_buff *skb);
+void ath_debug_airtime(struct ath_softc *sc,
+		       struct ath_node *an,
+		       u32 rx, u32 tx);
 #else
 static inline void ath_debug_rate_stats(struct ath_softc *sc,
 					struct ath_rx_status *rs,
 					struct sk_buff *skb)
 {
 }
+static inline void ath_debug_airtime(struct ath_softc *sc,
+			      struct ath_node *an,
+			      u32 rx, u32 tx)
+{
+}
 #endif /* CPTCFG_ATH9K_STATION_STATISTICS */
 
 #endif /* DEBUG_H */
--- a/drivers/net/wireless/ath/ath9k/debug_sta.c
+++ b/drivers/net/wireless/ath/ath9k/debug_sta.c
@@ -242,6 +242,59 @@ static const struct file_operations fops
 	.llseek = default_llseek,
 };
 
+void ath_debug_airtime(struct ath_softc *sc,
+		struct ath_node *an,
+		u32 rx,
+		u32 tx)
+{
+	struct ath_airtime_stats *astats = &an->airtime_stats;
+
+	astats->rx_airtime += rx;
+	astats->tx_airtime += tx;
+}
+
+static ssize_t read_airtime(struct file *file, char __user *user_buf,
+			size_t count, loff_t *ppos)
+{
+	struct ath_node *an = file->private_data;
+	struct ath_airtime_stats *astats;
+	static const char *qname[4] = {
+		"VO", "VI", "BE", "BK"
+	};
+	u32 len = 0, size = 256;
+	char *buf;
+	size_t retval;
+	int i;
+
+	buf = kzalloc(size, GFP_KERNEL);
+	if (buf == NULL)
+		return -ENOMEM;
+
+	astats = &an->airtime_stats;
+
+	len += scnprintf(buf + len, size - len, "RX: %u us\n", astats->rx_airtime);
+	len += scnprintf(buf + len, size - len, "TX: %u us\n", astats->tx_airtime);
+	len += scnprintf(buf + len, size - len, "Deficit: ");
+	for (i = 0; i < 4; i++)
+		len += scnprintf(buf+len, size - len, "%s: %lld us ", qname[i], an->airtime_deficit[i]);
+	if (len < size)
+		buf[len++] = '\n';
+
+	retval = simple_read_from_buffer(user_buf, count, ppos, buf, len);
+	kfree(buf);
+
+	return retval;
+}
+
+
+static const struct file_operations fops_airtime = {
+	.read = read_airtime,
+	.open = simple_open,
+	.owner = THIS_MODULE,
+	.llseek = default_llseek,
+};
+
+
 void ath9k_sta_add_debugfs(struct ieee80211_hw *hw,
 			   struct ieee80211_vif *vif,
 			   struct ieee80211_sta *sta,
@@ -251,4 +304,5 @@ void ath9k_sta_add_debugfs(struct ieee80
 
 	debugfs_create_file("node_aggr", S_IRUGO, dir, an, &fops_node_aggr);
 	debugfs_create_file("node_recv", S_IRUGO, dir, an, &fops_node_recv);
+	debugfs_create_file("airtime", S_IRUGO, dir, an, &fops_airtime);
 }
--- a/drivers/net/wireless/ath/ath9k/init.c
+++ b/drivers/net/wireless/ath/ath9k/init.c
@@ -620,6 +620,8 @@ static int ath9k_init_softc(u16 devid, s
 
 	/* Will be cleared in ath9k_start() */
 	set_bit(ATH_OP_INVALID, &common->op_flags);
+	sc->airtime_flags = (AIRTIME_USE_TX | AIRTIME_USE_RX |
+			     AIRTIME_USE_NEW_QUEUES);
 
 	sc->sc_ah = ah;
 	sc->dfs_detector = dfs_pattern_detector_init(common, NL80211_DFS_UNSET);
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -70,10 +70,10 @@ static bool ath9k_has_pending_frames(str
 		goto out;
 
 	if (txq->mac80211_qnum >= 0) {
-		struct list_head *list;
+		struct ath_acq *acq;
 
-		list = &sc->cur_chan->acq[txq->mac80211_qnum];
-		if (!list_empty(list))
+		acq = &sc->cur_chan->acq[txq->mac80211_qnum];
+		if (!list_empty(&acq->acq_new) || !list_empty(&acq->acq_old))
 			pending = true;
 	}
 out:
--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -991,6 +991,70 @@ static void ath9k_apply_ampdu_details(st
 	}
 }
 
+static void ath_rx_count_airtime(struct ath_softc *sc,
+				 struct ath_rx_status *rs,
+				 struct sk_buff *skb)
+{
+	struct ath_node *an;
+	struct ath_acq *acq;
+	struct ath_vif *avp;
+	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+	struct ath_hw *ah = sc->sc_ah;
+	struct ath_common *common = ath9k_hw_common(ah);
+	struct ieee80211_sta *sta;
+	struct ieee80211_rx_status *rxs;
+	const struct ieee80211_rate *rate;
+	bool is_sgi, is_40, is_sp;
+	int phy;
+	u16 len = rs->rs_datalen;
+	u32 airtime = 0;
+	u8 tidno, acno;
+
+	if (!ieee80211_is_data(hdr->frame_control))
+		return;
+
+	rcu_read_lock();
+
+	sta = ieee80211_find_sta_by_ifaddr(sc->hw, hdr->addr2, NULL);
+	if (!sta)
+		goto exit;
+	an = (struct ath_node *) sta->drv_priv;
+	avp = (struct ath_vif *) an->vif->drv_priv;
+	tidno = skb->priority & IEEE80211_QOS_CTL_TID_MASK;
+	acno = TID_TO_WME_AC(tidno);
+	acq = &avp->chanctx->acq[acno];
+
+	rxs = IEEE80211_SKB_RXCB(skb);
+
+	is_sgi = !!(rxs->flag & RX_FLAG_SHORT_GI);
+	is_40 = !!(rxs->flag & RX_FLAG_40MHZ);
+	is_sp = !!(rxs->flag & RX_FLAG_SHORTPRE);
+
+	if (!!(rxs->flag & RX_FLAG_HT)) {
+		/* MCS rates */
+
+		airtime += ath_pkt_duration(sc, rxs->rate_idx, len,
+					is_40, is_sgi, is_sp);
+	} else {
+
+		phy = IS_CCK_RATE(rs->rs_rate) ? WLAN_RC_PHY_CCK : WLAN_RC_PHY_OFDM;
+		rate = &common->sbands[rxs->band].bitrates[rxs->rate_idx];
+		airtime += ath9k_hw_computetxtime(ah, phy, rate->bitrate * 100,
+						len, rxs->rate_idx, is_sp);
+	}
+
+ 	if (!!(sc->airtime_flags & AIRTIME_USE_RX)) {
+		spin_lock_bh(&acq->lock);
+		an->airtime_deficit[acno] -= airtime;
+		if (an->airtime_deficit[acno] <= 0)
+			__ath_tx_queue_tid(sc, ATH_AN_2_TID(an, tidno));
+		spin_unlock_bh(&acq->lock);
+	}
+	ath_debug_airtime(sc, an, airtime, 0);
+exit:
+	rcu_read_unlock();
+}
+
 int ath_rx_tasklet(struct ath_softc *sc, int flush, bool hp)
 {
 	struct ath_rxbuf *bf;
@@ -1137,6 +1201,7 @@ int ath_rx_tasklet(struct ath_softc *sc,
 		ath9k_antenna_check(sc, &rs);
 		ath9k_apply_ampdu_details(sc, &rs, rxs);
 		ath_debug_rate_stats(sc, &rs, skb);
+		ath_rx_count_airtime(sc, &rs, skb);
 
 		hdr = (struct ieee80211_hdr *)skb->data;
 		if (ieee80211_is_ack(hdr->frame_control))
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -125,21 +125,44 @@ void ath_txq_unlock_complete(struct ath_
 		ath_tx_status(hw, skb);
 }
 
-static void ath_tx_queue_tid(struct ath_softc *sc, struct ath_txq *txq,
-			     struct ath_atx_tid *tid)
+void __ath_tx_queue_tid(struct ath_softc *sc, struct ath_atx_tid *tid)
 {
-	struct list_head *list;
 	struct ath_vif *avp = (struct ath_vif *) tid->an->vif->drv_priv;
 	struct ath_chanctx *ctx = avp->chanctx;
+	struct ath_acq *acq;
+	struct list_head *tid_list;
+	u8 acno = TID_TO_WME_AC(tid->tidno);
 
-	if (!ctx)
+	if (!ctx || !list_empty(&tid->list))
 		return;
 
-	list = &ctx->acq[TID_TO_WME_AC(tid->tidno)];
-	if (list_empty(&tid->list))
-		list_add_tail(&tid->list, list);
+
+	acq = &ctx->acq[acno];
+	if ((sc->airtime_flags & AIRTIME_USE_NEW_QUEUES) &&
+	    tid->an->airtime_deficit[acno] > 0)
+		tid_list = &acq->acq_new;
+	else
+		tid_list = &acq->acq_old;
+
+	list_add_tail(&tid->list, tid_list);
 }
 
+void ath_tx_queue_tid(struct ath_softc *sc, struct ath_atx_tid *tid)
+{
+	struct ath_vif *avp = (struct ath_vif *) tid->an->vif->drv_priv;
+	struct ath_chanctx *ctx = avp->chanctx;
+	struct ath_acq *acq;
+
+	if (!ctx || !list_empty(&tid->list))
+		return;
+
+	acq = &ctx->acq[TID_TO_WME_AC(tid->tidno)];
+	spin_lock_bh(&acq->lock);
+	__ath_tx_queue_tid(sc, tid);
+	spin_unlock_bh(&acq->lock);
+}
+
+
 void ath9k_wake_tx_queue(struct ieee80211_hw *hw, struct ieee80211_txq *queue)
 {
 	struct ath_softc *sc = hw->priv;
@@ -154,7 +177,7 @@ void ath9k_wake_tx_queue(struct ieee8021
 	ath_txq_lock(sc, txq);
 
 	tid->has_queued = true;
-	ath_tx_queue_tid(sc, txq, tid);
+	ath_tx_queue_tid(sc, tid);
 	ath_txq_schedule(sc, txq);
 
 	ath_txq_unlock(sc, txq);
@@ -684,7 +707,7 @@ static void ath_tx_complete_aggr(struct
 
 		skb_queue_splice_tail(&bf_pending, &tid->retry_q);
 		if (!an->sleeping) {
-			ath_tx_queue_tid(sc, txq, tid);
+			ath_tx_queue_tid(sc, tid);
 
 			if (ts->ts_status & (ATH9K_TXERR_FILT | ATH9K_TXERR_XRETRY))
 				tid->clear_ps_filter = true;
@@ -712,6 +735,53 @@ static bool bf_is_ampdu_not_probing(stru
     return bf_isampdu(bf) && !(info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE);
 }
 
+static void ath_tx_count_airtime(struct ath_softc *sc, struct ath_txq *txq,
+				 struct ath_buf *bf, struct ath_tx_status *ts)
+{
+	struct ath_node *an;
+	struct ath_acq *acq = &sc->cur_chan->acq[txq->mac80211_qnum];
+	struct sk_buff *skb;
+	struct ieee80211_hdr *hdr;
+	struct ieee80211_hw *hw = sc->hw;
+	struct ieee80211_tx_rate rates[4];
+	struct ieee80211_sta *sta;
+	int i;
+	u32 airtime = 0;
+
+	skb = bf->bf_mpdu;
+	if(!skb)
+		return;
+
+	hdr = (struct ieee80211_hdr *)skb->data;
+	memcpy(rates, bf->rates, sizeof(rates));
+
+	rcu_read_lock();
+
+	sta = ieee80211_find_sta_by_ifaddr(hw, hdr->addr1, hdr->addr2);
+	if(!sta)
+		goto exit;
+
+
+	an = (struct ath_node *) sta->drv_priv;
+
+	airtime += ts->duration * (ts->ts_longretry + 1);
+
+	for(i=0; i < ts->ts_rateindex; i++)
+		airtime += ath9k_hw_get_duration(sc->sc_ah, bf->bf_desc, i) * rates[i].count;
+
+	if (!!(sc->airtime_flags & AIRTIME_USE_TX)) {
+		spin_lock_bh(&acq->lock);
+		an->airtime_deficit[txq->mac80211_qnum] -= airtime;
+		if (an->airtime_deficit[txq->mac80211_qnum] <= 0)
+			__ath_tx_queue_tid(sc, ath_get_skb_tid(sc, an, skb));
+		spin_unlock_bh(&acq->lock);
+	}
+	ath_debug_airtime(sc, an, 0, airtime);
+
+exit:
+	rcu_read_unlock();
+}
+
 static void ath_tx_process_buffer(struct ath_softc *sc, struct ath_txq *txq,
 				  struct ath_tx_status *ts, struct ath_buf *bf,
 				  struct list_head *bf_head)
@@ -733,6 +803,7 @@ static void ath_tx_process_buffer(struct
 
 	ts->duration = ath9k_hw_get_duration(sc->sc_ah, bf->bf_desc,
 					     ts->ts_rateindex);
+	ath_tx_count_airtime(sc, txq, bf, ts);
 
 	hdr = (struct ieee80211_hdr *) bf->bf_mpdu->data;
 	sta = ieee80211_find_sta_by_ifaddr(hw, hdr->addr1, hdr->addr2);
@@ -1094,8 +1165,8 @@ finish:
  * width  - 0 for 20 MHz, 1 for 40 MHz
  * half_gi - to use 4us v/s 3.6 us for symbol time
  */
-static u32 ath_pkt_duration(struct ath_softc *sc, u8 rix, int pktlen,
-			    int width, int half_gi, bool shortPreamble)
+u32 ath_pkt_duration(struct ath_softc *sc, u8 rix, int pktlen,
+		     int width, int half_gi, bool shortPreamble)
 {
 	u32 nbits, nsymbits, duration, nsymbols;
 	int streams;
@@ -1493,7 +1564,7 @@ ath_tx_form_burst(struct ath_softc *sc,
 }
 
 static bool ath_tx_sched_aggr(struct ath_softc *sc, struct ath_txq *txq,
-			      struct ath_atx_tid *tid, bool *stop)
+			      struct ath_atx_tid *tid)
 {
 	struct ath_buf *bf;
 	struct ieee80211_tx_info *tx_info;
@@ -1515,7 +1586,6 @@ static bool ath_tx_sched_aggr(struct ath
 	if ((aggr && txq->axq_ampdu_depth >= ATH_AGGR_MIN_QDEPTH) ||
 	    (!aggr && txq->axq_depth >= ATH_NON_AGGR_MIN_QDEPTH)) {
 		__skb_queue_tail(&tid->retry_q, bf->bf_mpdu);
-		*stop = true;
 		return false;
 	}
 
@@ -1639,7 +1709,7 @@ void ath_tx_aggr_wakeup(struct ath_softc
 		ath_txq_lock(sc, txq);
 		tid->clear_ps_filter = true;
 		if (ath_tid_has_buffered(tid)) {
-			ath_tx_queue_tid(sc, txq, tid);
+			ath_tx_queue_tid(sc, tid);
 			ath_txq_schedule(sc, txq);
 		}
 		ath_txq_unlock_complete(sc, txq);
@@ -1956,9 +2026,10 @@ void ath_tx_cleanupq(struct ath_softc *s
 void ath_txq_schedule(struct ath_softc *sc, struct ath_txq *txq)
 {
 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
-	struct ath_atx_tid *tid, *last_tid;
+	struct ath_atx_tid *tid;
 	struct list_head *tid_list;
-	bool sent = false;
+	struct ath_acq *acq;
+	bool active = AIRTIME_ACTIVE(sc->airtime_flags);
 
 	if (txq->mac80211_qnum < 0)
 		return;
@@ -1967,48 +2038,55 @@ void ath_txq_schedule(struct ath_softc *
 		return;
 
 	spin_lock_bh(&sc->chan_lock);
-	tid_list = &sc->cur_chan->acq[txq->mac80211_qnum];
-
-	if (list_empty(tid_list)) {
-		spin_unlock_bh(&sc->chan_lock);
-		return;
-	}
-
 	rcu_read_lock();
+	acq = &sc->cur_chan->acq[txq->mac80211_qnum];
 
-	last_tid = list_entry(tid_list->prev, struct ath_atx_tid, list);
-	while (!list_empty(tid_list)) {
-		bool stop = false;
-
-		if (sc->cur_chan->stopped)
-			break;
-
-		tid = list_first_entry(tid_list, struct ath_atx_tid, list);
-		list_del_init(&tid->list);
+	if (sc->cur_chan->stopped)
+		goto out;
 
-		if (ath_tx_sched_aggr(sc, txq, tid, &stop))
-			sent = true;
+begin:
+	tid_list = &acq->acq_new;
+	if (list_empty(tid_list)) {
+		tid_list = &acq->acq_old;
+		if (list_empty(tid_list))
+			goto out;
+	}
+	tid = list_first_entry(tid_list, struct ath_atx_tid, list);
 
-		/*
-		 * add tid to round-robin queue if more frames
-		 * are pending for the tid
-		 */
-		if (ath_tid_has_buffered(tid))
-			ath_tx_queue_tid(sc, txq, tid);
+	if (active && tid->an->airtime_deficit[txq->mac80211_qnum] <= 0) {
+		spin_lock_bh(&acq->lock);
+		tid->an->airtime_deficit[txq->mac80211_qnum] += ATH_AIRTIME_QUANTUM;
+		list_move_tail(&tid->list, &acq->acq_old);
+		spin_unlock_bh(&acq->lock);
+		goto begin;
+	}
 
-		if (stop)
-			break;
+	if (!ath_tid_has_buffered(tid)) {
+		spin_lock_bh(&acq->lock);
+		if ((tid_list == &acq->acq_new) && !list_empty(&acq->acq_old))
+			list_move_tail(&tid->list, &acq->acq_old);
+		else {
+			list_del_init(&tid->list);
+		}
+		spin_unlock_bh(&acq->lock);
+		goto begin;
+	}
 
-		if (tid == last_tid) {
-			if (!sent)
-				break;
 
-			sent = false;
-			last_tid = list_entry(tid_list->prev,
-					      struct ath_atx_tid, list);
+	/*
+	 * If we succeed in scheduling something, immediately restart to make
+	 * sure we keep the HW busy.
+	 */
+	if(ath_tx_sched_aggr(sc, txq, tid)) {
+		if (!active) {
+			spin_lock_bh(&acq->lock);
+			list_move_tail(&tid->list, &acq->acq_old);
+			spin_unlock_bh(&acq->lock);
 		}
+		goto begin;
 	}
 
+out:
 	rcu_read_unlock();
 	spin_unlock_bh(&sc->chan_lock);
 }
@@ -2862,6 +2940,9 @@ void ath_tx_node_init(struct ath_softc *
 	struct ath_atx_tid *tid;
 	int tidno, acno;
 
+	for (acno = 0; acno < IEEE80211_NUM_ACS; acno++)
+		an->airtime_deficit[acno] = ATH_AIRTIME_QUANTUM;
+
 	for (tidno = 0; tidno < IEEE80211_NUM_TIDS; tidno++) {
 		tid = ath_node_to_tid(an, tidno);
 		tid->an        = an;