add support for ack timeout estimation in ath9k driver

Add dynamic ack timeout estimation algorithm based on ack frame RX timestamp, TX frame timestamp and frame duration.

Signed-off-by Lorenzo Bianconi <[email protected]>

---

drivers/net/wireless/ath/ath.h          |   2 +
drivers/net/wireless/ath/ath9k/ath9k.h  |   3 +
drivers/net/wireless/ath/ath9k/dynack.c | 293 ++++++++++++++++++++++++++++++++
drivers/net/wireless/ath/ath9k/dynack.h |  81 +++++++++
drivers/net/wireless/ath/ath9k/hw.c     |   2 +
drivers/net/wireless/ath/ath9k/hw.h     |   3 +
6 files changed, 384 insertions(+)

create mode 100644 drivers/net/wireless/ath/ath9k/dynack.c create mode 100644 drivers/net/wireless/ath/ath9k/dynack.h

drivers/net/wireless/ath/ath.h +2 -0

index fd9e530..4e51072 100644
@@ -234,6 +234,7 @@ void ath_printk(const char *level, const struct ath_common *common,
 *	AR9462.
 * @ATH_DBG_DFS: radar datection
 * @ATH_DBG_WOW: Wake on Wireless
+ * @ATH_DBG_DYNACK: dynack handling
 * @ATH_DBG_ANY: enable all debugging
 *
 * The debug level is used to control the amount and type of debugging output

@@ -261,6 +262,7 @@ enum ATH_DEBUG {
 	ATH_DBG_MCI		= 0x00008000,
 	ATH_DBG_DFS		= 0x00010000,
 	ATH_DBG_WOW		= 0x00020000,
+	ATH_DBG_DYNACK		= 0x00040000,
 	ATH_DBG_ANY		= 0xffffffff
 };
 

drivers/net/wireless/ath/ath9k/ath9k.h +3 -0

index 11b5e4d..65a2587 100644
@@ -272,6 +272,9 @@ struct ath_node {
 	struct ath_rx_rate_stats rx_rate_stats;
 #endif
 	u8 key_idx[4];
+
+	u32 ackto;
+	struct list_head list;
 };
 
 struct ath_tx_control {

drivers/net/wireless/ath/ath9k/dynack.c new file +9 -0

new file mode 100644
index 0000000..50297e7
@@ -0,0 +1,293 @@
+/*
+ * Copyright 2014, Lorenzo Bianconi <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include "ath9k.h"
+#include "hw.h"

drivers/net/wireless/ath/ath9k/dynack.c new file +31 -0

+/**
+ * ath_dynack_get_sifs - get sifs time based on phy used
+ * @ah: ath hw
+ * @phy: phy used
+ */
+static inline u32 ath_dynack_get_sifs(struct ath_hw *ah, int phy)
+{
+	u32 sifs = CCK_SIFS_TIME;
+
+	if (phy == WLAN_RC_PHY_OFDM) {
+		if (IS_CHAN_QUARTER_RATE(ah->curchan))
+			sifs = OFDM_SIFS_TIME_QUARTER;
+		else if (IS_CHAN_HALF_RATE(ah->curchan))
+			sifs = OFDM_SIFS_TIME_HALF;
+		else
+			sifs = OFDM_SIFS_TIME;
+	}
+	return sifs;
+}
+
+static inline bool ath_dynack_bssidmask(struct ath_hw *ah, const u8 *mac)
+{
+	int i;
+	struct ath_common *common = ath9k_hw_common(ah);
+
+	for (i = 0; i < ETH_ALEN; i++) {
+		if ((common->macaddr[i] & common->bssidmask[i]) !=
+		    (mac[i] & common->bssidmask[i]))
+			return false;
+	}
+

drivers/net/wireless/ath/ath9k/dynack.c new file +54 -0

+		da->ackto = to;
+		ath_dbg(common, DYNACK, "ack timeout %u slottime %u\n",
+			da->ackto, slottime);
+		ath9k_hw_setslottime(ah, slottime);
+		ath9k_hw_set_ack_timeout(ah, da->ackto);
+		ath9k_hw_set_cts_timeout(ah, da->ackto);
+	}
+}
+
+/**
+ * ath_dynack_compute_to - compute ack timeout
+ * @ah: ath hw
+ *
+ * should be called while holding qlock
+ */
+static void ath_dynack_compute_to(struct ath_hw *ah)
+{
+	u32 ackto, ack_ts;
+	u8 *dst, *src;
+	struct ieee80211_sta *sta;
+	struct ath_node *an;
+	struct ts_info *st_ts;
+	struct ath_dynack *da = &ah->dynack;
+
+	rcu_read_lock();
+
+	while (da->st_rbf.h_rb != da->st_rbf.t_rb &&
+	       da->ack_rbf.h_rb != da->ack_rbf.t_rb) {
+		ack_ts = da->ack_rbf.tstamp[da->ack_rbf.h_rb];
+		st_ts = &da->st_rbf.ts[da->st_rbf.h_rb];
+		dst = da->st_rbf.addr[da->st_rbf.h_rb].h_dest;
+		src = da->st_rbf.addr[da->st_rbf.h_rb].h_src;
+
+		ath_dbg(ath9k_hw_common(ah), DYNACK,
+			"ack_ts %u st_ts %u st_dur %u [%u-%u]\n",
+			ack_ts, st_ts->tstamp, st_ts->dur,
+			da->ack_rbf.h_rb, da->st_rbf.h_rb);
+
+		if (ack_ts > st_ts->tstamp + st_ts->dur) {
+			ackto = ack_ts - st_ts->tstamp - st_ts->dur;
+
+			if (ackto < MAX_DELAY) {
+				sta = ieee80211_find_sta_by_ifaddr(ah->hw, dst,
+								   src);
+				if (sta) {
+					an = (struct ath_node *)sta->drv_priv;
+					an->ackto = DYNACK_EWMA((u32)ackto,
+								an->ackto);
+					ath_dbg(ath9k_hw_common(ah), DYNACK,
+						"%pM to %u\n", dst, an->ackto);
+					if (time_is_before_jiffies(da->lto)) {
+						ath_dynack_compute_ackto(ah);
+						da->lto = jiffies + COMPUTE_TO;
+					}

drivers/net/wireless/ath/ath9k/dynack.c new file +155 -0

+}
+
+/**
+ * ath_dynack_sample_tx_ts - status ts sampling method
+ * @ah: ath hw
+ * @skb: socket buffer
+ * @ts: tx status info
+ *
+ */
+void ath_dynack_sample_tx_ts(struct ath_hw *ah, struct sk_buff *skb,
+			     struct ath_tx_status *ts)
+{
+	u8 ridx;
+	struct ieee80211_hdr *hdr;
+	struct ath_dynack *da = &ah->dynack;
+	struct ath_common *common = ath9k_hw_common(ah);
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+
+	if ((info->flags & IEEE80211_TX_CTL_NO_ACK) || da->fix_to)
+		return;
+
+	spin_lock_bh(&da->qlock);
+
+	hdr = (struct ieee80211_hdr *)skb->data;
+
+	/* late ack */
+	if (ts->ts_status & ATH9K_TXERR_XRETRY) {
+		if (ieee80211_is_assoc_req(hdr->frame_control) ||
+		    ieee80211_is_assoc_resp(hdr->frame_control)) {
+			ath_dbg(common, DYNACK, "late ack\n");
+			ath9k_hw_setslottime(ah, (LATEACK_TO - 3) / 2);
+			ath9k_hw_set_ack_timeout(ah, LATEACK_TO);
+			ath9k_hw_set_cts_timeout(ah, LATEACK_TO);
+			da->lto = jiffies + LATEACK_DELAY;
+		}
+
+		spin_unlock_bh(&da->qlock);
+		return;
+	}
+
+	ridx = ts->ts_rateindex;
+
+	da->st_rbf.ts[da->st_rbf.t_rb].tstamp = ts->ts_tstamp;
+	da->st_rbf.ts[da->st_rbf.t_rb].dur = ts->duration[ts->ts_rateindex];
+	ether_addr_copy(da->st_rbf.addr[da->st_rbf.t_rb].h_dest, hdr->addr1);
+	ether_addr_copy(da->st_rbf.addr[da->st_rbf.t_rb].h_src, hdr->addr2);
+
+	if (!(info->status.rates[ridx].flags & IEEE80211_TX_RC_MCS)) {
+		u32 phy, sifs;
+		const struct ieee80211_rate *rate;
+		struct ieee80211_tx_rate *rates = info->status.rates;
+
+		rate = &common->sbands[info->band].bitrates[rates[ridx].idx];
+		if (info->band == IEEE80211_BAND_2GHZ &&
+		    !(rate->flags & IEEE80211_RATE_ERP_G))
+			phy = WLAN_RC_PHY_CCK;
+		else
+			phy = WLAN_RC_PHY_OFDM;
+
+		sifs = ath_dynack_get_sifs(ah, phy);
+		da->st_rbf.ts[da->st_rbf.t_rb].dur -= sifs;
+	}
+
+	ath_dbg(common, DYNACK, "{%pM} tx sample %u [dur %u][h %u-t %u]\n",
+		hdr->addr1, da->st_rbf.ts[da->st_rbf.t_rb].tstamp,
+		da->st_rbf.ts[da->st_rbf.t_rb].dur, da->st_rbf.h_rb,
+		(da->st_rbf.t_rb + 1) % ATH_DYN_BUF);
+
+	INCR(da->st_rbf.t_rb, ATH_DYN_BUF);
+	if (da->st_rbf.t_rb == da->st_rbf.h_rb)
+		INCR(da->st_rbf.h_rb, ATH_DYN_BUF);
+
+	ath_dynack_compute_to(ah);
+
+	spin_unlock_bh(&da->qlock);
+}
+EXPORT_SYMBOL(ath_dynack_sample_tx_ts);
+
+/**
+ * ath_dynack_sample_ack_ts - ack ts sampling method
+ * @ah: ath hw
+ * @skb: socket buffer
+ * @ts: rx timestamp
+ *
+ */
+void ath_dynack_sample_ack_ts(struct ath_hw *ah, struct sk_buff *skb,
+			      u32 ts)
+{
+	struct ath_dynack *da = &ah->dynack;
+	struct ath_common *common = ath9k_hw_common(ah);
+	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+
+	if (!ath_dynack_bssidmask(ah, hdr->addr1) || da->fix_to)
+		return;
+
+	spin_lock_bh(&da->qlock);
+	da->ack_rbf.tstamp[da->ack_rbf.t_rb] = ts;
+
+	ath_dbg(common, DYNACK, "rx sample %u [h %u-t %u]\n",
+		da->ack_rbf.tstamp[da->ack_rbf.t_rb],
+		da->ack_rbf.h_rb, (da->ack_rbf.t_rb + 1) % ATH_DYN_BUF);
+
+	INCR(da->ack_rbf.t_rb, ATH_DYN_BUF);
+	if (da->ack_rbf.t_rb == da->ack_rbf.h_rb)
+		INCR(da->ack_rbf.h_rb, ATH_DYN_BUF);
+
+	ath_dynack_compute_to(ah);
+
+	spin_unlock_bh(&da->qlock);
+}
+EXPORT_SYMBOL(ath_dynack_sample_ack_ts);
+
+/**
+ * ath_dynack_reset - reset dynack processing
+ * @ah: ath hw
+ *
+ */
+void ath_dynack_reset(struct ath_hw *ah)
+{
+	/* ackto = slottime + sifs + air delay */
+	u32 ackto = ATH9K_SLOT_TIME_9 + 16 + 64;
+	struct ath_dynack *da = &ah->dynack;
+
+	da->lto = jiffies;
+	da->ackto = ackto;
+
+	da->st_rbf.t_rb = 0;
+	da->st_rbf.h_rb = 0;
+	da->ack_rbf.t_rb = 0;
+	da->ack_rbf.h_rb = 0;
+
+	/* init acktimeout */
+	ath9k_hw_setslottime(ah, (ackto - 3) / 2);
+	ath9k_hw_set_ack_timeout(ah, ackto);
+	ath9k_hw_set_cts_timeout(ah, ackto);
+}
+EXPORT_SYMBOL(ath_dynack_reset);
+
+/**
+ * ath_dynack_init - init dynack data structure
+ * @ah: ath hw
+ *
+ */
+void ath_dynack_init(struct ath_hw *ah)
+{
+	struct ath_dynack *da = &ah->dynack;
+
+	memset(da, 0, sizeof(struct ath_dynack));
+
+	spin_lock_init(&da->qlock);
+	INIT_LIST_HEAD(&da->nodes);
+
+	ath_dynack_reset(ah);
+}
+

drivers/net/wireless/ath/ath9k/dynack.h new file +81 -0

new file mode 100644
index 0000000..386f176
@@ -0,0 +1,81 @@
+/*
+ * Copyright 2014, Lorenzo Bianconi <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef DYNACK_H
+#define DYNACK_H
+
+#define ATH_DYN_BUF	64
+
+struct ath_hw;
+
+/**
+ * ath_dyn_rxbuf - ack frame ring buffer
+ */
+struct ath_dyn_rxbuf {
+	u16 h_rb, t_rb;
+	u32 tstamp[ATH_DYN_BUF];
+};
+
+struct ts_info {
+	u32 tstamp;
+	u32 dur;
+};
+
+struct haddr_pair {
+	u8 h_dest[ETH_ALEN];
+	u8 h_src[ETH_ALEN];
+};
+/**
+ * ath_dyn_txbuf - tx frame ring buffer
+ */
+struct ath_dyn_txbuf {
+	u16 h_rb, t_rb;
+	struct haddr_pair addr[ATH_DYN_BUF];
+	struct ts_info ts[ATH_DYN_BUF];
+};
+
+/**
+ * ath_dynack - dyn ack processing info
+ * @fix_to: use static ack timeout
+ * @ackto: current ack timeout
+ * @lto: last ack timeout computation
+ * @nodes: ath_node linked list
+ * @qlock: ts queue spinlock
+ * @ack_rbf: ack ts ring buffer
+ * @st_rbf: status ts ring buffer
+ */
+struct ath_dynack {
+	bool fix_to;
+	int ackto;
+	unsigned long lto;
+
+	struct list_head nodes;
+
+	/* protect timestamp queue access */
+	spinlock_t qlock;
+	struct ath_dyn_rxbuf ack_rbf;
+	struct ath_dyn_txbuf st_rbf;
+};
+
+#if defined(CONFIG_ATH9K_DYNACK)
+void ath_dynack_reset(struct ath_hw *ah);
+void ath_dynack_init(struct ath_hw *ah);
+void ath_dynack_sample_ack_ts(struct ath_hw *ah, struct sk_buff *skb, u32 ts);
+void ath_dynack_sample_tx_ts(struct ath_hw *ah, struct sk_buff *skb,
+			     struct ath_tx_status *ts);
+#else
+static inline void ath_dynack_reset(struct ath_hw *ah) {}
+static inline void ath_dynack_init(struct ath_hw *ah) {}
+static inline void ath_dynack_sample_ack_ts(struct ath_hw *ah,
+					    struct sk_buff *skb, u32 ts) {}
+static inline void ath_dynack_sample_tx_ts(struct ath_hw *ah,
+					   struct sk_buff *skb,
+					   struct ath_tx_status *ts) {}
+#endif
+
+#endif /* DYNACK_H */

drivers/net/wireless/ath/ath9k/hw.c +2 -0

index e88896c..9a6b113 100644
@@ -647,6 +647,8 @@ int ath9k_hw_init(struct ath_hw *ah)
 		return ret;
 	}
 
+	ath_dynack_init(ah);
+
 	return 0;
 }
 EXPORT_SYMBOL(ath9k_hw_init);

drivers/net/wireless/ath/ath9k/hw.h +3 -0

index f36d971..b9eef33 100644
@@ -29,6 +29,7 @@
 #include "reg.h"
 #include "phy.h"
 #include "btcoex.h"
+#include "dynack.h"
 
 #include "../regd.h"
 

@@ -924,6 +925,8 @@ struct ath_hw {
 	int (*external_reset)(void);
 
 	const struct firmware *eeprom_blob;
+
+	struct ath_dynack dynack;
 };
 
 struct ath_bus_ops {

Signature · 6 lines

1.9.1

_______________________________________________
ath9k-devel mailing list
ath9k-devel at lists.ath9k.org
https://lists.ath9k.org/mailman/listinfo/ath9k-devel

drivers/net/wireless/ath/ath9k/dynack.c line 70

Quoted 11 lines

drivers/net/wireless/ath/ath9k/dynack.c new file +10 -0

+{
+	struct ath_node *an;
+	u32 to = 0;
+	struct ath_dynack *da = &ah->dynack;
+	struct ath_common *common = ath9k_hw_common(ah);
+
 
+	list_for_each_entry(an, &da->nodes, list)
+		if (an->ackto > to)
+			to = an->ackto;
+

This list parsing would probably need rcu protection like:

	rcu_read_lock();
	list_for_each_entry(an, &da->nodes, list)
		if (an->ackto > to)
			to = an->ackto;
	rcu_read_unlock();

I am not sure that you need to call the entire function with spin_lock as you do it now.

drivers/net/wireless/ath/ath9k/dynack.c line 74

Quoted 4 lines

drivers/net/wireless/ath/ath9k/dynack.c new file +4 -0

+	if (to && da->ackto != to) {
+		u32 slottime;
+
+		slottime = (to - 3) / 2;

Should the case to < 3 be covered or is it safe to have potentially slottime = 0 ?

Quoted 51 lines

drivers/net/wireless/ath/ath9k/dynack.c new file +51 -0

+/**
+ * ath_dynack_compute_to - compute ack timeout
+ * @ah: ath hw
+ *
+ * should be called while holding qlock
+ */
+static void ath_dynack_compute_to(struct ath_hw *ah)
+{
+	u32 ackto, ack_ts;
+	u8 *dst, *src;
+	struct ieee80211_sta *sta;
+	struct ath_node *an;
+	struct ts_info *st_ts;
+	struct ath_dynack *da = &ah->dynack;
+
+	rcu_read_lock();
+
+	while (da->st_rbf.h_rb != da->st_rbf.t_rb &&
+	       da->ack_rbf.h_rb != da->ack_rbf.t_rb) {
+		ack_ts = da->ack_rbf.tstamp[da->ack_rbf.h_rb];
+		st_ts = &da->st_rbf.ts[da->st_rbf.h_rb];
+		dst = da->st_rbf.addr[da->st_rbf.h_rb].h_dest;
+		src = da->st_rbf.addr[da->st_rbf.h_rb].h_src;
+
+		ath_dbg(ath9k_hw_common(ah), DYNACK,
+			"ack_ts %u st_ts %u st_dur %u [%u-%u]\n",
+			ack_ts, st_ts->tstamp, st_ts->dur,
+			da->ack_rbf.h_rb, da->st_rbf.h_rb);
+
+		if (ack_ts > st_ts->tstamp + st_ts->dur) {
+			ackto = ack_ts - st_ts->tstamp - st_ts->dur;
+
+			if (ackto < MAX_DELAY) {
+				sta = ieee80211_find_sta_by_ifaddr(ah->hw, dst,
+								   src);
+				if (sta) {
+					an = (struct ath_node *)sta->drv_priv;
+					an->ackto = DYNACK_EWMA((u32)ackto,
+								an->ackto);
+					ath_dbg(ath9k_hw_common(ah), DYNACK,
+						"%pM to %u\n", dst, an->ackto);
+					if (time_is_before_jiffies(da->lto)) {
+						ath_dynack_compute_ackto(ah);
+						da->lto = jiffies + COMPUTE_TO;
+					}
+				}
+				INCR(da->ack_rbf.h_rb, ATH_DYN_BUF);
+			}
+			INCR(da->st_rbf.h_rb, ATH_DYN_BUF);
+		} else {
+			INCR(da->ack_rbf.h_rb, ATH_DYN_BUF);

drivers/net/wireless/ath/ath9k/dynack.c line 138

Quoted 4 lines

drivers/net/wireless/ath/ath9k/dynack.c new file +4 -0

+		}
+	}
+
+	rcu_read_unlock();

I think it is sufficient to have the rcu_read_unlock just around ieee80211_find_sta_by_ifaddr(). So the lock does not need to include the whole while loop under lock.

Hi Lorenzo,

My comments are inline.

Quoted 64 lines

Add dynamic ack timeout estimation algorithm based on ack frame RX timestamp, TX frame timestamp and frame duration.

Signed-off-by Lorenzo Bianconi <[email protected]>

---

drivers/net/wireless/ath/ath.h          |   2 +
drivers/net/wireless/ath/ath9k/ath9k.h  |   3 +
drivers/net/wireless/ath/ath9k/dynack.c | 293 ++++++++++++++++++++++++++++++++
drivers/net/wireless/ath/ath9k/dynack.h |  81 +++++++++
drivers/net/wireless/ath/ath9k/hw.c     |   2 +
drivers/net/wireless/ath/ath9k/hw.h     |   3 +
6 files changed, 384 insertions(+)

create mode 100644 drivers/net/wireless/ath/ath9k/dynack.c create mode 100644 drivers/net/wireless/ath/ath9k/dynack.h

drivers/net/wireless/ath/ath.h +2 -0

index fd9e530..4e51072 100644
@@ -234,6 +234,7 @@ void ath_printk(const char *level, const struct ath_common *common,
 *    AR9462.
 * @ATH_DBG_DFS: radar datection
 * @ATH_DBG_WOW: Wake on Wireless
+ * @ATH_DBG_DYNACK: dynack handling
 * @ATH_DBG_ANY: enable all debugging
 *
 * The debug level is used to control the amount and type of debugging output

@@ -261,6 +262,7 @@ enum ATH_DEBUG {
      ATH_DBG_MCI             = 0x00008000,
      ATH_DBG_DFS             = 0x00010000,
      ATH_DBG_WOW             = 0x00020000,
+     ATH_DBG_DYNACK          = 0x00040000,
      ATH_DBG_ANY             = 0xffffffff
 };
 

drivers/net/wireless/ath/ath9k/ath9k.h +3 -0

index 11b5e4d..65a2587 100644
@@ -272,6 +272,9 @@ struct ath_node {
      struct ath_rx_rate_stats rx_rate_stats;
 #endif
      u8 key_idx[4];
+
+     u32 ackto;
+     struct list_head list;
 };
 
 struct ath_tx_control {

drivers/net/wireless/ath/ath9k/dynack.c new file +9 -0

new file mode 100644
index 0000000..50297e7
@@ -0,0 +1,293 @@
+/*
+ * Copyright 2014, Lorenzo Bianconi <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include "ath9k.h"
+#include "hw.h"

drivers/net/wireless/ath/ath9k/dynack.c line 19

Quoted 10 lines

drivers/net/wireless/ath/ath9k/dynack.c new file +10 -0

+#include "dynack.h"
+
+#define COMPUTE_TO           (5 * HZ)
+#define LATEACK_DELAY                (10 * HZ)
+#define LATEACK_TO           256
+#define MAX_DELAY            300
+#define EWMA_LEVEL           75
+#define DYNACK_EWMA(old, new)        \
+     (((new) * (100 - EWMA_LEVEL) + (old) * EWMA_LEVEL) / 100)
+

You could change this EWMA calculation as we did it in Minstrel to use powers of two as the calculation speed increased. This would change :
- EWMA_DIV from 100 to 2^7
- EWMA_LEVEL from 75 (/EWMA_DIV=100) to 2^6 + 2^5 (/EWMA_DIV=128)

Note that this changes EWMA_DIV - EWMA_LEVEL from 25 to 2^5 and keeps EWMA_LEVEL / EWMA_DIV == 0.75.

Something like this:

(quoted diff) +2 -0

+#define EWMA_LEVEL     96      /* ewma weighting factor [/EWMA_DIV] */
+#define EWMA_DIV       128

static inline int
dynack_ewma(int old, int new, int weight)
{
+ return (new * (EWMA_DIV - weight) + old * weight) / EWMA_DIV;
}

Quoted 36 lines

drivers/net/wireless/ath/ath9k/dynack.c new file +35 -0

+/**
+ * ath_dynack_get_sifs - get sifs time based on phy used
+ * @ah: ath hw
+ * @phy: phy used
+ */
+static inline u32 ath_dynack_get_sifs(struct ath_hw *ah, int phy)
+{
+     u32 sifs = CCK_SIFS_TIME;
+
+     if (phy == WLAN_RC_PHY_OFDM) {
+             if (IS_CHAN_QUARTER_RATE(ah->curchan))
+                     sifs = OFDM_SIFS_TIME_QUARTER;
+             else if (IS_CHAN_HALF_RATE(ah->curchan))
+                     sifs = OFDM_SIFS_TIME_HALF;
+             else
+                     sifs = OFDM_SIFS_TIME;
+     }
+     return sifs;
+}
+
+static inline bool ath_dynack_bssidmask(struct ath_hw *ah, const u8 *mac)
+{
+     int i;
+     struct ath_common *common = ath9k_hw_common(ah);
+
+     for (i = 0; i < ETH_ALEN; i++) {
+             if ((common->macaddr[i] & common->bssidmask[i]) !=
+                 (mac[i] & common->bssidmask[i]))
+                     return false;
+     }
+
+     return true;
+}
+
+/**

drivers/net/wireless/ath/ath9k/dynack.c line 60

Quoted 6 lines

drivers/net/wireless/ath/ath9k/dynack.c new file +6 -0

+ * ath_dynack_set_ackto - compute ack timeout based on sta timeout
+ * @ah: ath hw
+ *
+ * should be called while holding qlock
+ */
+static void ath_dynack_compute_ackto(struct ath_hw *ah)

The function name does not match the name in the comment above (ath_dynack_set_ackto != ath_dynack_compute_ackto).

drivers/net/wireless/ath/ath9k/dynack.c line 70

Quoted 11 lines

drivers/net/wireless/ath/ath9k/dynack.c new file +10 -0

+{
+     struct ath_node *an;
+     u32 to = 0;
+     struct ath_dynack *da = &ah->dynack;
+     struct ath_common *common = ath9k_hw_common(ah);
+
 
+     list_for_each_entry(an, &da->nodes, list)
+             if (an->ackto > to)
+                     to = an->ackto;
+

This list parsing would probably need rcu protection like:

        rcu_read_lock();
        list_for_each_entry(an, &da->nodes, list)
                if (an->ackto > to)
                        to = an->ackto;
        rcu_read_unlock();

I am not sure that you need to call the entire function with spin_lock as you do it now.

drivers/net/wireless/ath/ath9k/dynack.c line 74

Quoted 4 lines

drivers/net/wireless/ath/ath9k/dynack.c new file +4 -0

+     if (to && da->ackto != to) {
+             u32 slottime;
+
+             slottime = (to - 3) / 2;

Should the case to < 3 be covered or is it safe to have potentially slottime = 0 ?

Quoted 55 lines

drivers/net/wireless/ath/ath9k/dynack.c new file +54 -0

+             da->ackto = to;
+             ath_dbg(common, DYNACK, "ack timeout %u slottime %u\n",
+                     da->ackto, slottime);
+             ath9k_hw_setslottime(ah, slottime);
+             ath9k_hw_set_ack_timeout(ah, da->ackto);
+             ath9k_hw_set_cts_timeout(ah, da->ackto);
+     }
+}
+
+/**
+ * ath_dynack_compute_to - compute ack timeout
+ * @ah: ath hw
+ *
+ * should be called while holding qlock
+ */
+static void ath_dynack_compute_to(struct ath_hw *ah)
+{
+     u32 ackto, ack_ts;
+     u8 *dst, *src;
+     struct ieee80211_sta *sta;
+     struct ath_node *an;
+     struct ts_info *st_ts;
+     struct ath_dynack *da = &ah->dynack;
+
+     rcu_read_lock();
+
+     while (da->st_rbf.h_rb != da->st_rbf.t_rb &&
+            da->ack_rbf.h_rb != da->ack_rbf.t_rb) {
+             ack_ts = da->ack_rbf.tstamp[da->ack_rbf.h_rb];
+             st_ts = &da->st_rbf.ts[da->st_rbf.h_rb];
+             dst = da->st_rbf.addr[da->st_rbf.h_rb].h_dest;
+             src = da->st_rbf.addr[da->st_rbf.h_rb].h_src;
+
+             ath_dbg(ath9k_hw_common(ah), DYNACK,
+                     "ack_ts %u st_ts %u st_dur %u [%u-%u]\n",
+                     ack_ts, st_ts->tstamp, st_ts->dur,
+                     da->ack_rbf.h_rb, da->st_rbf.h_rb);
+
+             if (ack_ts > st_ts->tstamp + st_ts->dur) {
+                     ackto = ack_ts - st_ts->tstamp - st_ts->dur;
+
+                     if (ackto < MAX_DELAY) {
+                             sta = ieee80211_find_sta_by_ifaddr(ah->hw, dst,
+                                                                src);
+                             if (sta) {
+                                     an = (struct ath_node *)sta->drv_priv;
+                                     an->ackto = DYNACK_EWMA((u32)ackto,
+                                                             an->ackto);
+                                     ath_dbg(ath9k_hw_common(ah), DYNACK,
+                                             "%pM to %u\n", dst, an->ackto);
+                                     if (time_is_before_jiffies(da->lto)) {
+                                             ath_dynack_compute_ackto(ah);
+                                             da->lto = jiffies + COMPUTE_TO;
+                                     }

drivers/net/wireless/ath/ath9k/dynack.c line 138

Quoted 10 lines

drivers/net/wireless/ath/ath9k/dynack.c new file +10 -0

+                             }
+                             INCR(da->ack_rbf.h_rb, ATH_DYN_BUF);
+                     }
+                     INCR(da->st_rbf.h_rb, ATH_DYN_BUF);
+             } else {
+                     INCR(da->ack_rbf.h_rb, ATH_DYN_BUF);
+             }
+     }
+
+     rcu_read_unlock();

I think it is sufficient to have the rcu_read_unlock just around ieee80211_find_sta_by_ifaddr(). So the lock does not need to include the whole while loop under lock.

Greetings Thomas

Quoted 275 lines

drivers/net/wireless/ath/ath9k/dynack.c new file +155 -0

+}
+
+/**
+ * ath_dynack_sample_tx_ts - status ts sampling method
+ * @ah: ath hw
+ * @skb: socket buffer
+ * @ts: tx status info
+ *
+ */
+void ath_dynack_sample_tx_ts(struct ath_hw *ah, struct sk_buff *skb,
+                          struct ath_tx_status *ts)
+{
+     u8 ridx;
+     struct ieee80211_hdr *hdr;
+     struct ath_dynack *da = &ah->dynack;
+     struct ath_common *common = ath9k_hw_common(ah);
+     struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+
+     if ((info->flags & IEEE80211_TX_CTL_NO_ACK) || da->fix_to)
+             return;
+
+     spin_lock_bh(&da->qlock);
+
+     hdr = (struct ieee80211_hdr *)skb->data;
+
+     /* late ack */
+     if (ts->ts_status & ATH9K_TXERR_XRETRY) {
+             if (ieee80211_is_assoc_req(hdr->frame_control) ||
+                 ieee80211_is_assoc_resp(hdr->frame_control)) {
+                     ath_dbg(common, DYNACK, "late ack\n");
+                     ath9k_hw_setslottime(ah, (LATEACK_TO - 3) / 2);
+                     ath9k_hw_set_ack_timeout(ah, LATEACK_TO);
+                     ath9k_hw_set_cts_timeout(ah, LATEACK_TO);
+                     da->lto = jiffies + LATEACK_DELAY;
+             }
+
+             spin_unlock_bh(&da->qlock);
+             return;
+     }
+
+     ridx = ts->ts_rateindex;
+
+     da->st_rbf.ts[da->st_rbf.t_rb].tstamp = ts->ts_tstamp;
+     da->st_rbf.ts[da->st_rbf.t_rb].dur = ts->duration[ts->ts_rateindex];
+     ether_addr_copy(da->st_rbf.addr[da->st_rbf.t_rb].h_dest, hdr->addr1);
+     ether_addr_copy(da->st_rbf.addr[da->st_rbf.t_rb].h_src, hdr->addr2);
+
+     if (!(info->status.rates[ridx].flags & IEEE80211_TX_RC_MCS)) {
+             u32 phy, sifs;
+             const struct ieee80211_rate *rate;
+             struct ieee80211_tx_rate *rates = info->status.rates;
+
+             rate = &common->sbands[info->band].bitrates[rates[ridx].idx];
+             if (info->band == IEEE80211_BAND_2GHZ &&
+                 !(rate->flags & IEEE80211_RATE_ERP_G))
+                     phy = WLAN_RC_PHY_CCK;
+             else
+                     phy = WLAN_RC_PHY_OFDM;
+
+             sifs = ath_dynack_get_sifs(ah, phy);
+             da->st_rbf.ts[da->st_rbf.t_rb].dur -= sifs;
+     }
+
+     ath_dbg(common, DYNACK, "{%pM} tx sample %u [dur %u][h %u-t %u]\n",
+             hdr->addr1, da->st_rbf.ts[da->st_rbf.t_rb].tstamp,
+             da->st_rbf.ts[da->st_rbf.t_rb].dur, da->st_rbf.h_rb,
+             (da->st_rbf.t_rb + 1) % ATH_DYN_BUF);
+
+     INCR(da->st_rbf.t_rb, ATH_DYN_BUF);
+     if (da->st_rbf.t_rb == da->st_rbf.h_rb)
+             INCR(da->st_rbf.h_rb, ATH_DYN_BUF);
+
+     ath_dynack_compute_to(ah);
+
+     spin_unlock_bh(&da->qlock);
+}
+EXPORT_SYMBOL(ath_dynack_sample_tx_ts);
+
+/**
+ * ath_dynack_sample_ack_ts - ack ts sampling method
+ * @ah: ath hw
+ * @skb: socket buffer
+ * @ts: rx timestamp
+ *
+ */
+void ath_dynack_sample_ack_ts(struct ath_hw *ah, struct sk_buff *skb,
+                           u32 ts)
+{
+     struct ath_dynack *da = &ah->dynack;
+     struct ath_common *common = ath9k_hw_common(ah);
+     struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+
+     if (!ath_dynack_bssidmask(ah, hdr->addr1) || da->fix_to)
+             return;
+
+     spin_lock_bh(&da->qlock);
+     da->ack_rbf.tstamp[da->ack_rbf.t_rb] = ts;
+
+     ath_dbg(common, DYNACK, "rx sample %u [h %u-t %u]\n",
+             da->ack_rbf.tstamp[da->ack_rbf.t_rb],
+             da->ack_rbf.h_rb, (da->ack_rbf.t_rb + 1) % ATH_DYN_BUF);
+
+     INCR(da->ack_rbf.t_rb, ATH_DYN_BUF);
+     if (da->ack_rbf.t_rb == da->ack_rbf.h_rb)
+             INCR(da->ack_rbf.h_rb, ATH_DYN_BUF);
+
+     ath_dynack_compute_to(ah);
+
+     spin_unlock_bh(&da->qlock);
+}
+EXPORT_SYMBOL(ath_dynack_sample_ack_ts);
+
+/**
+ * ath_dynack_reset - reset dynack processing
+ * @ah: ath hw
+ *
+ */
+void ath_dynack_reset(struct ath_hw *ah)
+{
+     /* ackto = slottime + sifs + air delay */
+     u32 ackto = ATH9K_SLOT_TIME_9 + 16 + 64;
+     struct ath_dynack *da = &ah->dynack;
+
+     da->lto = jiffies;
+     da->ackto = ackto;
+
+     da->st_rbf.t_rb = 0;
+     da->st_rbf.h_rb = 0;
+     da->ack_rbf.t_rb = 0;
+     da->ack_rbf.h_rb = 0;
+
+     /* init acktimeout */
+     ath9k_hw_setslottime(ah, (ackto - 3) / 2);
+     ath9k_hw_set_ack_timeout(ah, ackto);
+     ath9k_hw_set_cts_timeout(ah, ackto);
+}
+EXPORT_SYMBOL(ath_dynack_reset);
+
+/**
+ * ath_dynack_init - init dynack data structure
+ * @ah: ath hw
+ *
+ */
+void ath_dynack_init(struct ath_hw *ah)
+{
+     struct ath_dynack *da = &ah->dynack;
+
+     memset(da, 0, sizeof(struct ath_dynack));
+
+     spin_lock_init(&da->qlock);
+     INIT_LIST_HEAD(&da->nodes);
+
+     ath_dynack_reset(ah);
+}
+

drivers/net/wireless/ath/ath9k/dynack.h new file +81 -0

new file mode 100644
index 0000000..386f176
@@ -0,0 +1,81 @@
+/*
+ * Copyright 2014, Lorenzo Bianconi <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef DYNACK_H
+#define DYNACK_H
+
+#define ATH_DYN_BUF  64
+
+struct ath_hw;
+
+/**
+ * ath_dyn_rxbuf - ack frame ring buffer
+ */
+struct ath_dyn_rxbuf {
+     u16 h_rb, t_rb;
+     u32 tstamp[ATH_DYN_BUF];
+};
+
+struct ts_info {
+     u32 tstamp;
+     u32 dur;
+};
+
+struct haddr_pair {
+     u8 h_dest[ETH_ALEN];
+     u8 h_src[ETH_ALEN];
+};
+/**
+ * ath_dyn_txbuf - tx frame ring buffer
+ */
+struct ath_dyn_txbuf {
+     u16 h_rb, t_rb;
+     struct haddr_pair addr[ATH_DYN_BUF];
+     struct ts_info ts[ATH_DYN_BUF];
+};
+
+/**
+ * ath_dynack - dyn ack processing info
+ * @fix_to: use static ack timeout
+ * @ackto: current ack timeout
+ * @lto: last ack timeout computation
+ * @nodes: ath_node linked list
+ * @qlock: ts queue spinlock
+ * @ack_rbf: ack ts ring buffer
+ * @st_rbf: status ts ring buffer
+ */
+struct ath_dynack {
+     bool fix_to;
+     int ackto;
+     unsigned long lto;
+
+     struct list_head nodes;
+
+     /* protect timestamp queue access */
+     spinlock_t qlock;
+     struct ath_dyn_rxbuf ack_rbf;
+     struct ath_dyn_txbuf st_rbf;
+};
+
+#if defined(CONFIG_ATH9K_DYNACK)
+void ath_dynack_reset(struct ath_hw *ah);
+void ath_dynack_init(struct ath_hw *ah);
+void ath_dynack_sample_ack_ts(struct ath_hw *ah, struct sk_buff *skb, u32 ts);
+void ath_dynack_sample_tx_ts(struct ath_hw *ah, struct sk_buff *skb,
+                          struct ath_tx_status *ts);
+#else
+static inline void ath_dynack_reset(struct ath_hw *ah) {}
+static inline void ath_dynack_init(struct ath_hw *ah) {}
+static inline void ath_dynack_sample_ack_ts(struct ath_hw *ah,
+                                         struct sk_buff *skb, u32 ts) {}
+static inline void ath_dynack_sample_tx_ts(struct ath_hw *ah,
+                                        struct sk_buff *skb,
+                                        struct ath_tx_status *ts) {}
+#endif
+
+#endif /* DYNACK_H */

drivers/net/wireless/ath/ath9k/hw.c +2 -0

index e88896c..9a6b113 100644
@@ -647,6 +647,8 @@ int ath9k_hw_init(struct ath_hw *ah)
              return ret;
      }
 
+     ath_dynack_init(ah);
+
      return 0;
 }
 EXPORT_SYMBOL(ath9k_hw_init);

drivers/net/wireless/ath/ath9k/hw.h +3 -0

index f36d971..b9eef33 100644
@@ -29,6 +29,7 @@
 #include "reg.h"
 #include "phy.h"
 #include "btcoex.h"
+#include "dynack.h"
 
 #include "../regd.h"
 

@@ -924,6 +925,8 @@ struct ath_hw {
      int (*external_reset)(void);
 
      const struct firmware *eeprom_blob;
+
+     struct ath_dynack dynack;
 };
 

Quoted 8 lines

drivers/net/wireless/ath/ath9k/hw.h +0 -1

 struct ath_bus_ops {
--

1.9.1

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+/*
+ * Copyright 2014, Lorenzo Bianconi <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */

Quoted 7 lines · Lorenzo Bianconi

+/*
+ * Copyright 2014, Lorenzo Bianconi <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */

I have not reviewed the patches, but the ath9k driver is licensed under ISC. Introducing a file with GPLv2 license is bound to cause complications and I think might require legal clearance from a QCA employee maintaining ath9k.

Right now, I am not sure if there is an official maintainer for ath9k, but is there any specific reason why you have chosen GPLv2 ?

Sujith

Hi Sujith,

Quoted 18 lines

Quoted 7 lines · Lorenzo Bianconi

+/*
+ * Copyright 2014, Lorenzo Bianconi <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */

I have not reviewed the patches, but the ath9k driver is licensed under ISC. Introducing a file with GPLv2 license is bound to cause complications and I think might require legal clearance from a QCA employee maintaining ath9k.

Right now, I am not sure if there is an official maintainer for ath9k, but is there any specific reason why you have chosen GPLv2 ?

Quoted 1 line

Sujith

Nope. I didn't know ath9k is under ISC license. I think I can replace GPLv2 license with an ISC one.
Best regards,

Lorenzo

Signature · 7 lines

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This patchset adds support for estimation of the ack timeout (dynack) in ath9k driver. Ath9k dynack computes the ack timeout based on ack frame RX timestamp, TX frame timestamp and frame duration.

Ath9k dynack has been tested in indoor environment using AR9223 chipset (running 3.15.3 kernel) configured as AP and using AR9280 chipset (running 3.16.0-rc3) configured as STA. Ath9k dynack needs to be tested on a long distance link in outdoor environment.

Lorenzo Bianconi (10):
ath9k: export methods related to ack timeout estimation
ath9k: add duration field to ath_tx_status
ath9k: add dynamic ack timeout estimation
ath9k: add config for (en|dis)abling ack timeout estimation
ath9k: do not overwrite ack timeout estimation
ath9k: add sampling methods for (tx|rx) timestamp
ath9k: enable control frame reception
ath9k: add debugfs support for dynack
ath9k: disable dynack algorithm when coverage class is set
ath9k: add ath_node linked list

drivers/net/wireless/ath/ath.h              |   2 +
drivers/net/wireless/ath/ath9k/Kconfig      |   7 +
drivers/net/wireless/ath/ath9k/Makefile     |   3 +
drivers/net/wireless/ath/ath9k/ar9002_mac.c |   7 +
drivers/net/wireless/ath/ath9k/ar9003_mac.c |   9 +
drivers/net/wireless/ath/ath9k/ath9k.h      |   3 +
drivers/net/wireless/ath/ath9k/debug.c      |  82 ++++++++
drivers/net/wireless/ath/ath9k/dynack.c     | 293 ++++++++++++++++++++++++++++
drivers/net/wireless/ath/ath9k/dynack.h     |  81 ++++++++
drivers/net/wireless/ath/ath9k/hw.c         |  16 +-
drivers/net/wireless/ath/ath9k/hw.h         |   7 +
drivers/net/wireless/ath/ath9k/mac.h        |   1 +
drivers/net/wireless/ath/ath9k/main.c       |  11 ++
drivers/net/wireless/ath/ath9k/recv.c       |   7 +-
drivers/net/wireless/ath/ath9k/xmit.c       |   5 +
15 files changed, 530 insertions(+), 4 deletions(-)

create mode 100644 drivers/net/wireless/ath/ath9k/dynack.c create mode 100644 drivers/net/wireless/ath/ath9k/dynack.h

Signature · 6 lines

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