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Commit 53a76b58 authored by Christian Lamparter's avatar Christian Lamparter Committed by John W. Linville
Browse files

ar9170: improve network latency 



AR9170 has the bad habit of choking when traffic builds up.
Tests have shown that this can partially be attributed to
a huge buildup of backlogged frames.

Signed-off-by: default avatarChristian Lamparter <chunkeey@googlemail.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 5e0ec316

drivers/net/wireless/ath/ar9170/ar9170.h

+2 −0
Original line number Diff line number Diff line
@@ -152,6 +152,8 @@ struct ar9170_sta_tid { 


#define AR9170_NUM_TX_STATUS		128

#define AR9170_NUM_TX_AGG_MAX		30

#define AR9170_NUM_TX_LIMIT_HARD       AR9170_TXQ_DEPTH

#define AR9170_NUM_TX_LIMIT_SOFT       (AR9170_TXQ_DEPTH - 10)



struct ar9170 {

	struct ieee80211_hw *hw;

drivers/net/wireless/ath/ar9170/main.c

+16 −18
Original line number Diff line number Diff line
@@ -430,7 +430,7 @@ void ar9170_tx_callback(struct ar9170 *ar, struct sk_buff *skb) 
	spin_lock_irqsave(&ar->tx_stats_lock, flags);

	ar->tx_stats[queue].len--;



	if (skb_queue_empty(&ar->tx_pending[queue])) {

	if (ar->tx_stats[queue].len < AR9170_NUM_TX_LIMIT_SOFT) {

#ifdef AR9170_QUEUE_STOP_DEBUG

		printk(KERN_DEBUG "%s: wake queue %d\n",

		       wiphy_name(ar->hw->wiphy), queue);
@@ -1716,6 +1716,21 @@ static void ar9170_tx(struct ar9170 *ar) 


	for (i = 0; i < __AR9170_NUM_TXQ; i++) {

		spin_lock_irqsave(&ar->tx_stats_lock, flags);

		frames = min(ar->tx_stats[i].limit - ar->tx_stats[i].len,

			     skb_queue_len(&ar->tx_pending[i]));



		if (remaining_space < frames) {

#ifdef AR9170_QUEUE_DEBUG

			printk(KERN_DEBUG "%s: tx quota reached queue:%d, "

			       "remaining slots:%d, needed:%d\n",

			       wiphy_name(ar->hw->wiphy), i, remaining_space,

			       frames);

#endif /* AR9170_QUEUE_DEBUG */

			frames = remaining_space;

		}



		ar->tx_stats[i].len += frames;

		ar->tx_stats[i].count += frames;

		if (ar->tx_stats[i].len >= ar->tx_stats[i].limit) {

#ifdef AR9170_QUEUE_DEBUG

			printk(KERN_DEBUG "%s: queue %d full\n",
@@ -1733,25 +1748,8 @@ static void ar9170_tx(struct ar9170 *ar) 
			__ar9170_dump_txstats(ar);

#endif /* AR9170_QUEUE_STOP_DEBUG */

			ieee80211_stop_queue(ar->hw, i);

			spin_unlock_irqrestore(&ar->tx_stats_lock, flags);

			continue;

		}



		frames = min(ar->tx_stats[i].limit - ar->tx_stats[i].len,

			     skb_queue_len(&ar->tx_pending[i]));



		if (remaining_space < frames) {

#ifdef AR9170_QUEUE_DEBUG

			printk(KERN_DEBUG "%s: tx quota reached queue:%d, "

			       "remaining slots:%d, needed:%d\n",

			       wiphy_name(ar->hw->wiphy), i, remaining_space,

			       frames);

#endif /* AR9170_QUEUE_DEBUG */

			frames = remaining_space;

		}



		ar->tx_stats[i].len += frames;

		ar->tx_stats[i].count += frames;

		spin_unlock_irqrestore(&ar->tx_stats_lock, flags);



		if (!frames)