ath9k: add dynamic ACK timeout estimation
authorLorenzo Bianconi <lorenzo.bianconi83@gmail.com>
Tue, 16 Sep 2014 00:13:09 +0000 (02:13 +0200)
committerJohn W. Linville <linville@tuxdriver.com>
Tue, 16 Sep 2014 20:18:30 +0000 (16:18 -0400)
Add dynamic ACK timeout estimation algorithm based on ACK frame RX timestamp,
TX frame timestamp and frame duration.

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
Tested-by: Philippe Duchein <wireless-dev@duchein.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
drivers/net/wireless/ath/ath.h
drivers/net/wireless/ath/ath9k/ath9k.h
drivers/net/wireless/ath/ath9k/dynack.c [new file with mode: 0644]
drivers/net/wireless/ath/ath9k/dynack.h [new file with mode: 0644]
drivers/net/wireless/ath/ath9k/hw.c
drivers/net/wireless/ath/ath9k/hw.h

index c1a4ade3277280409e250f5eb4729e40a894a5d2..a3b6e27d91219a54778114f2f8195713cf911e61 100644 (file)
@@ -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
@@ -262,6 +263,7 @@ enum ATH_DEBUG {
        ATH_DBG_DFS             = 0x00010000,
        ATH_DBG_WOW             = 0x00020000,
        ATH_DBG_CHAN_CTX        = 0x00040000,
+       ATH_DBG_DYNACK          = 0x00080000,
        ATH_DBG_ANY             = 0xffffffff
 };
 
index dd0f97f7f960100c251db3bcaa25e67cb747c609..8cd116efe3eac2d7aa3c4df69bafbc36b65f6fae 100644 (file)
@@ -274,6 +274,9 @@ 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 {
diff --git a/drivers/net/wireless/ath/ath9k/dynack.c b/drivers/net/wireless/ath/ath9k/dynack.c
new file mode 100644 (file)
index 0000000..6ae8e0b
--- /dev/null
@@ -0,0 +1,351 @@
+/*
+ * Copyright (c) 2014, Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "ath9k.h"
+#include "hw.h"
+#include "dynack.h"
+
+#define COMPUTE_TO             (5 * HZ)
+#define LATEACK_DELAY          (10 * HZ)
+#define LATEACK_TO             256
+#define MAX_DELAY              300
+#define EWMA_LEVEL             96
+#define EWMA_DIV               128
+
+/**
+ * ath_dynack_ewma - EWMA (Exponentially Weighted Moving Average) calculation
+ *
+ */
+static inline u32 ath_dynack_ewma(u32 old, u32 new)
+{
+       return (new * (EWMA_DIV - EWMA_LEVEL) + old * EWMA_LEVEL) / EWMA_DIV;
+}
+
+/**
+ * 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;
+}
+
+/**
+ * ath_dynack_bssidmask - filter out ACK frames based on BSSID mask
+ * @ah: ath hw
+ * @mac: receiver address
+ */
+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;
+}
+
+/**
+ * ath_dynack_compute_ackto - compute ACK timeout as the maximum STA timeout
+ * @ah: ath hw
+ *
+ * should be called while holding qlock
+ */
+static void ath_dynack_compute_ackto(struct ath_hw *ah)
+{
+       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;
+
+       if (to && da->ackto != to) {
+               u32 slottime;
+
+               slottime = (to - 3) / 2;
+               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 STA 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 = ath_dynack_ewma(an->ackto,
+                                                                   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);
+               }
+       }
+
+       rcu_read_unlock();
+}
+
+/**
+ * ath_dynack_sample_tx_ts - status timestamp 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->enabled)
+               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 timestamp 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->enabled)
+               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_node_init - init ath_node related info
+ * @ah: ath hw
+ * @an: ath node
+ *
+ */
+void ath_dynack_node_init(struct ath_hw *ah, struct ath_node *an)
+{
+       /* ackto = slottime + sifs + air delay */
+       u32 ackto = ATH9K_SLOT_TIME_9 + 16 + 64;
+       struct ath_dynack *da = &ah->dynack;
+
+       an->ackto = ackto;
+
+       spin_lock(&da->qlock);
+       list_add_tail(&an->list, &da->nodes);
+       spin_unlock(&da->qlock);
+}
+EXPORT_SYMBOL(ath_dynack_node_init);
+
+/**
+ * ath_dynack_node_deinit - deinit ath_node related info
+ * @ah: ath hw
+ * @an: ath node
+ *
+ */
+void ath_dynack_node_deinit(struct ath_hw *ah, struct ath_node *an)
+{
+       struct ath_dynack *da = &ah->dynack;
+
+       spin_lock(&da->qlock);
+       list_del(&an->list);
+       spin_unlock(&da->qlock);
+}
+EXPORT_SYMBOL(ath_dynack_node_deinit);
+
+/**
+ * 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);
+
+       ah->hw->wiphy->features |= NL80211_FEATURE_ACKTO_ESTIMATION;
+}
diff --git a/drivers/net/wireless/ath/ath9k/dynack.h b/drivers/net/wireless/ath/ath9k/dynack.h
new file mode 100644 (file)
index 0000000..6d7bef9
--- /dev/null
@@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2014, Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef DYNACK_H
+#define DYNACK_H
+
+#define ATH_DYN_BUF    64
+
+struct ath_hw;
+struct ath_node;
+
+/**
+ * struct ath_dyn_rxbuf - ACK frame ring buffer
+ * @h_rb: ring buffer head
+ * @t_rb: ring buffer tail
+ * @tstamp: ACK RX timestamp 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];
+};
+
+/**
+ * struct ath_dyn_txbuf - tx frame ring buffer
+ * @h_rb: ring buffer head
+ * @t_rb: ring buffer tail
+ * @addr: dest/src address pair for a given TX frame
+ * @ts: TX frame timestamp buffer
+ */
+struct ath_dyn_txbuf {
+       u16 h_rb, t_rb;
+       struct haddr_pair addr[ATH_DYN_BUF];
+       struct ts_info ts[ATH_DYN_BUF];
+};
+
+/**
+ * struct ath_dynack - dynack processing info
+ * @enabled: enable dyn ack processing
+ * @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 enabled;
+       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_node_init(struct ath_hw *ah, struct ath_node *an);
+void ath_dynack_node_deinit(struct ath_hw *ah, struct ath_node *an);
+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_init(struct ath_hw *ah) {}
+static inline void ath_dynack_node_init(struct ath_hw *ah,
+                                       struct ath_node *an) {}
+static inline void ath_dynack_node_deinit(struct ath_hw *ah,
+                                         struct ath_node *an) {}
+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 */
index ce395e23b54963ca82e24a2e58e3b1c30209439c..e71f824cb040e528386d4d9fac909b1631ee2d7c 100644 (file)
@@ -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);
index f36d971855db7fc4b950fc715855f6edc0ad63b1..b9eef3362fbb2fb955d478fed1acdf896ab27bf3 100644 (file)
@@ -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 {