ath9k: Add airtime fairness scheduler

This adds a patch that introduces airtime fairness scheduling to ath9k,
which can significantly improve network efficiency in mixed-rate
environments.

Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
This commit is contained in:
Toke Høiland-Jørgensen 2016-12-19 13:59:15 +01:00 committed by Felix Fietkau
parent b3a871dd3d
commit 47bc081e76
6 changed files with 104 additions and 7 deletions

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@ -0,0 +1,35 @@
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
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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>
---

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From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@toke.dk>
Date: Mon, 5 Dec 2016 13:27:38 +0200
Subject: [PATCH] ath9k: Turn ath_txq_lock/unlock() into static inlines.
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These are one-line functions that just call spin_lock/unlock_bh(); turn
them into static inlines to avoid the function call overhead.
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
@@ -558,6 +558,15 @@ static inline void ath_chanctx_check_act
#endif /* CPTCFG_ATH9K_CHANNEL_CONTEXT */
+static inline void ath_txq_lock(struct ath_softc *sc, struct ath_txq *txq)
+{
+ spin_lock_bh(&txq->axq_lock);
+}
+static inline void ath_txq_unlock(struct ath_softc *sc, struct ath_txq *txq)
+{
+ spin_unlock_bh(&txq->axq_lock);
+}
+
void ath_startrecv(struct ath_softc *sc);
bool ath_stoprecv(struct ath_softc *sc);
u32 ath_calcrxfilter(struct ath_softc *sc);
@@ -565,8 +574,6 @@ int ath_rx_init(struct ath_softc *sc, in
void ath_rx_cleanup(struct ath_softc *sc);
int ath_rx_tasklet(struct ath_softc *sc, int flush, bool hp);
struct ath_txq *ath_txq_setup(struct ath_softc *sc, int qtype, int subtype);
-void ath_txq_lock(struct ath_softc *sc, struct ath_txq *txq);
-void ath_txq_unlock(struct ath_softc *sc, struct ath_txq *txq);
void ath_txq_unlock_complete(struct ath_softc *sc, struct ath_txq *txq);
void ath_tx_cleanupq(struct ath_softc *sc, struct ath_txq *txq);
bool ath_drain_all_txq(struct ath_softc *sc);
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -98,18 +98,6 @@ static void ath_tx_status(struct ieee802
dev_kfree_skb(skb);
}
-void ath_txq_lock(struct ath_softc *sc, struct ath_txq *txq)
- __acquires(&txq->axq_lock)
-{
- spin_lock_bh(&txq->axq_lock);
-}
-
-void ath_txq_unlock(struct ath_softc *sc, struct ath_txq *txq)
- __releases(&txq->axq_lock)
-{
- spin_unlock_bh(&txq->axq_lock);
-}
-
void ath_txq_unlock_complete(struct ath_softc *sc, struct ath_txq *txq)
__releases(&txq->axq_lock)
{

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@ -1,6 +1,6 @@
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -827,6 +827,9 @@ static inline int ath9k_dump_btcoex(stru
@@ -837,6 +837,9 @@ static inline int ath9k_dump_btcoex(stru
#ifdef CPTCFG_MAC80211_LEDS
void ath_init_leds(struct ath_softc *sc);
void ath_deinit_leds(struct ath_softc *sc);
@ -10,7 +10,7 @@
#else
static inline void ath_init_leds(struct ath_softc *sc)
{
@@ -963,6 +966,13 @@ void ath_ant_comb_scan(struct ath_softc
@@ -973,6 +976,13 @@ void ath_ant_comb_scan(struct ath_softc
#define ATH9K_NUM_CHANCTX 2 /* supports 2 operating channels */
@ -24,7 +24,7 @@
struct ath_softc {
struct ieee80211_hw *hw;
struct device *dev;
@@ -1015,9 +1025,8 @@ struct ath_softc {
@@ -1025,9 +1035,8 @@ struct ath_softc {
spinlock_t chan_lock;
#ifdef CPTCFG_MAC80211_LEDS

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@ -18,7 +18,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
#include "common.h"
#include "debug.h"
@@ -973,6 +974,14 @@ struct ath_led {
@@ -983,6 +984,14 @@ struct ath_led {
struct led_classdev cdev;
};
@ -33,7 +33,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
struct ath_softc {
struct ieee80211_hw *hw;
struct device *dev;
@@ -1027,6 +1036,9 @@ struct ath_softc {
@@ -1037,6 +1046,9 @@ struct ath_softc {
#ifdef CPTCFG_MAC80211_LEDS
const char *led_default_trigger;
struct list_head leds;

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@ -10,7 +10,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -1038,6 +1038,7 @@ struct ath_softc {
@@ -1048,6 +1048,7 @@ struct ath_softc {
struct list_head leds;
#ifdef CONFIG_GPIOLIB
struct ath9k_gpio_chip *gpiochip;

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@ -329,7 +329,7 @@ Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
&ratesArray[0], cfgCtl,
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -1177,8 +1177,9 @@ static u8 ath_get_rate_txpower(struct at
@@ -1165,8 +1165,9 @@ static u8 ath_get_rate_txpower(struct at
if (is_40) {
u8 power_ht40delta;
struct ar5416_eeprom_def *eep = &ah->eeprom.def;