multi-rate retry and the 'minstrel' rate control for mac80211

@@ -337,8 +337,6 @@
 			unsigned long jiffies;
 			s8 rts_cts_rate_idx, alt_retry_rate_idx;
 			u8 retry_limit;
-			u8 icv_len;
-			u8 iv_len;
 		} control;
 		struct {
 			u64 ampdu_ack_map;

@@ -635,6 +633,8 @@
  */
 struct ieee80211_key_conf {
 	enum ieee80211_key_alg alg;
+	u8 icv_len;
+	u8 iv_len;
 	u8 hw_key_idx;
 	u8 flags;
 	s8 keyidx;

@@ -252,7 +252,7 @@
 		}
 
 		/* Hardware appends ICV. */
-		plcp_fragment_len += info->control.icv_len;
+		plcp_fragment_len += info->control.hw_key->icv_len;
 
 		key_idx = b43_kidx_to_fw(dev, key_idx);
 		mac_ctl |= (key_idx << B43_TXH_MAC_KEYIDX_SHIFT) &

@@ -260,7 +260,7 @@
 		mac_ctl |= (key->algorithm << B43_TXH_MAC_KEYALG_SHIFT) &
 			   B43_TXH_MAC_KEYALG;
 		wlhdr_len = ieee80211_hdrlen(fctl);
-		iv_len = min((size_t) info->control.iv_len,
+		iv_len = min((size_t) info->control.hw_key->iv_len,
 			     ARRAY_SIZE(txhdr->iv));
 		memcpy(txhdr->iv, ((u8 *) wlhdr) + wlhdr_len, iv_len);
 	}

@@ -243,7 +243,7 @@
 
 		if (key->enabled) {
 			/* Hardware appends ICV. */
-			plcp_fragment_len += info->control.icv_len;
+			plcp_fragment_len += info->control.hw_key->icv_len;
 
 			key_idx = b43legacy_kidx_to_fw(dev, key_idx);
 			mac_ctl |= (key_idx << B43legacy_TX4_MAC_KEYIDX_SHIFT) &

@@ -252,7 +252,7 @@
 				   B43legacy_TX4_MAC_KEYALG_SHIFT) &
 				   B43legacy_TX4_MAC_KEYALG;
 			wlhdr_len = ieee80211_hdrlen(wlhdr->frame_control);
-			iv_len = min((size_t)info->control.iv_len,
+			iv_len = min((size_t)info->control.hw_key->iv_len,
 				     ARRAY_SIZE(txhdr->iv));
 			memcpy(txhdr->iv, ((u8 *)wlhdr) + wlhdr_len, iv_len);
 		} else {

@@ -313,9 +313,6 @@
 {
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 
-	info->control.iv_len = WEP_IV_LEN;
-	info->control.icv_len = WEP_ICV_LEN;
-
 	if (!(tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)) {
 		if (ieee80211_wep_encrypt(tx->local, skb, tx->key))
 			return -1;

@@ -152,9 +152,6 @@
 	int len, tail;
 	u8 *pos;
 
-	info->control.icv_len = TKIP_ICV_LEN;
-	info->control.iv_len = TKIP_IV_LEN;
-
 	if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
 	    !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
 		/* hwaccel - with no need for preallocated room for IV/ICV */

@@ -374,9 +371,6 @@
 	u8 *pos, *pn;
 	int i;
 
-	info->control.icv_len = CCMP_MIC_LEN;
-	info->control.iv_len = CCMP_HDR_LEN;
-
 	if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
 	    !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
 		/* hwaccel - with no need for preallocated room for CCMP "

@@ -1164,7 +1164,7 @@
 
 	if (info->control.hw_key) {
 		keyidx = info->control.hw_key->hw_key_idx;
-		pktlen += info->control.icv_len;
+		pktlen += info->control.hw_key->icv_len;
 	}
 	ret = ah->ah_setup_tx_desc(ah, ds, pktlen,
 		ieee80211_get_hdrlen_from_skb(skb), AR5K_PKT_TYPE_NORMAL,

@@ -237,7 +237,7 @@
 
 	if (tx_info->control.hw_key) {
 		txctl->keyix = tx_info->control.hw_key->hw_key_idx;
-		txctl->frmlen += tx_info->control.icv_len;
+		txctl->frmlen += tx_info->control.hw_key->icv_len;
 
 		if (tx_info->control.hw_key->alg == ALG_WEP)
 			txctl->keytype = ATH9K_KEY_TYPE_WEP;

@@ -56,10 +56,10 @@
 	 * note that these lengths should only be added when
 	 * mac80211 does not generate it.
 	 */
-	overhead += tx_info->control.icv_len;
+	overhead += key->icv_len;
 
 	if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_IV))
-		overhead += tx_info->control.iv_len;
+		overhead += key->iv_len;
 
 	if (!(key->flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) {
 		if (key->alg == ALG_TKIP)

@@ -374,7 +374,7 @@
 	struct queue_entry *entry = rt2x00queue_get_entry(queue, Q_INDEX);
 	struct txentry_desc txdesc;
 	struct skb_frame_desc *skbdesc;
-	unsigned int iv_len = IEEE80211_SKB_CB(skb)->control.iv_len;
+	unsigned int iv_len;
 
 	if (unlikely(rt2x00queue_full(queue)))
 		return -EINVAL;

@@ -410,8 +410,11 @@
 	 * the frame so we can provide it to the driver seperately.
 	 */
 	if (test_bit(ENTRY_TXD_ENCRYPT, &txdesc.flags) &&
-	    !test_bit(ENTRY_TXD_ENCRYPT_IV, &txdesc.flags))
+	    !test_bit(ENTRY_TXD_ENCRYPT_IV, &txdesc.flags) &&
+		(IEEE80211_SKB_CB(skb)->control.hw_key != NULL)) {
+		iv_len = IEEE80211_SKB_CB(skb)->control.hw_key->iv_len;
 		rt2x00crypto_tx_remove_iv(skb, iv_len);
+	}
 
 	/*
 	 * It could be possible that the queue was corrupted and this

@@ -281,6 +281,20 @@
 	key->conf.alg = alg;
 	key->conf.keyidx = idx;
 	key->conf.keylen = key_len;
+	switch (alg) {
+	case ALG_WEP:
+		key->conf.iv_len = WEP_IV_LEN;
+		key->conf.icv_len = WEP_ICV_LEN;
+		break;
+	case ALG_TKIP:
+		key->conf.iv_len = TKIP_IV_LEN;
+		key->conf.icv_len = TKIP_ICV_LEN;
+		break;
+	case ALG_CCMP:
+		key->conf.iv_len = CCMP_HDR_LEN;
+		key->conf.icv_len = CCMP_MIC_LEN;
+		break;
+	}
 	memcpy(key->conf.key, key_data, key_len);
 	INIT_LIST_HEAD(&key->list);
 	INIT_LIST_HEAD(&key->todo);

@@ -292,6 +292,20 @@
 #define IEEE80211_TX_INFO_DRIVER_DATA_PTRS \
 	(IEEE80211_TX_INFO_DRIVER_DATA_SIZE / sizeof(void *))
 
+/* maximum number of alternate rate retry stages */
+#define IEEE80211_TX_MAX_ALTRATE	3
+
+/**
+ * struct ieee80211_tx_altrate - alternate rate selection/status
+ *
+ * @rate_idx: rate index to attempt to send with
+ * @limit: number of retries before fallback
+ */
+struct ieee80211_tx_altrate {
+	s8 rate_idx;
+	u8 limit;
+};
+
 /**
  * struct ieee80211_tx_info - skb transmit information
  *

@@ -335,12 +349,14 @@
 			struct ieee80211_key_conf *hw_key;
 			struct ieee80211_sta *sta;
 			unsigned long jiffies;
-			s8 rts_cts_rate_idx, alt_retry_rate_idx;
+			s8 rts_cts_rate_idx;
 			u8 retry_limit;
+			struct ieee80211_tx_altrate retries[IEEE80211_TX_MAX_ALTRATE];
 		} control;
 		struct {
 			u64 ampdu_ack_map;
 			int ack_signal;
+			struct ieee80211_tx_altrate retries[IEEE80211_TX_MAX_ALTRATE + 1];
 			u8 retry_count;
 			bool excessive_retries;
 			u8 ampdu_ack_len;

@@ -828,6 +844,9 @@
  *	within &struct ieee80211_vif.
  * @sta_data_size: size (in bytes) of the drv_priv data area
  *	within &struct ieee80211_sta.
+ *
+ * @max_altrates: maximum number of alternate rate retry stages
+ * @max_altrate_tries: maximum number of tries for each stage
  */
 struct ieee80211_hw {
 	struct ieee80211_conf conf;

@@ -844,6 +863,8 @@
 	u16 ampdu_queues;
 	u16 max_listen_interval;
 	s8 max_signal;
+	u8 max_altrates;
+	u8 max_altrate_tries;
 };
 
 struct ieee80211_hw *wiphy_to_hw(struct wiphy *wiphy);

@@ -900,11 +921,11 @@
 
 static inline struct ieee80211_rate *
 ieee80211_get_alt_retry_rate(const struct ieee80211_hw *hw,
-			     const struct ieee80211_tx_info *c)
+			     const struct ieee80211_tx_info *c, int idx)
 {
-	if (c->control.alt_retry_rate_idx < 0)
+	if (c->control.retries[idx].rate_idx < 0)
 		return NULL;
-	return &hw->wiphy->bands[c->band]->bitrates[c->control.alt_retry_rate_idx];
+	return &hw->wiphy->bands[c->band]->bitrates[c->control.retries[idx].rate_idx];
 }
 
 /**

@@ -208,7 +208,7 @@
 	txrate = ieee80211_get_tx_rate(dev->wl->hw, info);
 	rate = txrate ? txrate->hw_value : B43_CCK_RATE_1MB;
 	rate_ofdm = b43_is_ofdm_rate(rate);
-	fbrate = ieee80211_get_alt_retry_rate(dev->wl->hw, info) ? : txrate;
+	fbrate = ieee80211_get_alt_retry_rate(dev->wl->hw, info, 0) ? : txrate;
 	rate_fb = fbrate->hw_value;
 	rate_fb_ofdm = b43_is_ofdm_rate(rate_fb);
 

@@ -210,7 +210,7 @@
 
 	rate = tx_rate->hw_value;
 	rate_ofdm = b43legacy_is_ofdm_rate(rate);
-	rate_fb = ieee80211_get_alt_retry_rate(dev->wl->hw, info) ? : tx_rate;
+	rate_fb = ieee80211_get_alt_retry_rate(dev->wl->hw, info, 0) ? : tx_rate;
 	rate_fb_ofdm = b43legacy_is_ofdm_rate(rate_fb->hw_value);
 
 	txhdr->mac_frame_ctl = wlhdr->frame_control;

@@ -292,8 +292,8 @@
 	entry->plcp_len = cpu_to_le16(plcp_len);
 	entry->tx_buf = cpu_to_le32(mapping);
 	entry->frame_len = cpu_to_le32(skb->len);
-	entry->flags2 = info->control.alt_retry_rate_idx >= 0 ?
-		ieee80211_get_alt_retry_rate(dev, info)->bitrate << 4 : 0;
+	entry->flags2 = info->control.retries[0].rate_idx >= 0 ?
+		ieee80211_get_alt_retry_rate(dev, info, 0)->bitrate << 4 : 0;
 	entry->retry_limit = info->control.retry_limit;
 	entry->flags = cpu_to_le32(tx_flags);
 	__skb_queue_tail(&ring->queue, skb);

@@ -855,6 +855,7 @@
 	priv = dev->priv;
 	priv->pdev = pdev;
 
+	dev->max_altrates = 1;
 	SET_IEEE80211_DEV(dev, &pdev->dev);
 	pci_set_drvdata(pdev, dev);
 

@@ -454,15 +454,16 @@
 		if (unlikely(rsel.probe_idx >= 0)) {
 			info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
 			tx->flags |= IEEE80211_TX_PROBE_LAST_FRAG;
-			info->control.alt_retry_rate_idx = tx->rate_idx;
+			info->control.retries[0].rate_idx = tx->rate_idx;
+			info->control.retries[0].limit = tx->local->hw.max_altrate_tries;
 			tx->rate_idx = rsel.probe_idx;
-		} else
-			info->control.alt_retry_rate_idx = -1;
+		} else if (info->control.retries[0].limit == 0)
+			info->control.retries[0].rate_idx = -1;
 
 		if (unlikely(tx->rate_idx < 0))
 			return TX_DROP;
 	} else
-		info->control.alt_retry_rate_idx = -1;
+		info->control.retries[0].rate_idx = -1;
 
 	if (tx->sdata->bss_conf.use_cts_prot &&
 	    (tx->flags & IEEE80211_TX_FRAGMENTED) && (rsel.nonerp_idx >= 0)) {

@@ -521,7 +522,7 @@
 		 * frames.
 		 * TODO: The last fragment could still use multiple retry
 		 * rates. */
-		info->control.alt_retry_rate_idx = -1;
+		info->control.retries[0].rate_idx = -1;
 	}
 
 	/* Use CTS protection for unicast frames sent using extended rates if

@@ -551,7 +552,7 @@
 		int idx;
 
 		/* Do not use multiple retry rates when using RTS/CTS */
-		info->control.alt_retry_rate_idx = -1;
+		info->control.retries[0].rate_idx = -1;
 
 		/* Use min(data rate, max base rate) as CTS/RTS rate */
 		rate = &sband->bitrates[tx->rate_idx];

@@ -4588,6 +4588,7 @@
 		BIT(NL80211_IFTYPE_ADHOC);
 
 	hw->queues = b43_modparam_qos ? 4 : 1;
+	hw->max_altrates = 1;
 	SET_IEEE80211_DEV(hw, dev->dev);
 	if (is_valid_ether_addr(sprom->et1mac))
 		SET_IEEE80211_PERM_ADDR(hw, sprom->et1mac);

@@ -3710,6 +3710,7 @@
 		BIT(NL80211_IFTYPE_WDS) |
 		BIT(NL80211_IFTYPE_ADHOC);
 	hw->queues = 1; /* FIXME: hardware has more queues */
+	hw->max_altrates = 1;
 	SET_IEEE80211_DEV(hw, dev->dev);
 	if (is_valid_ether_addr(sprom->et1mac))
 		SET_IEEE80211_PERM_ADDR(hw, sprom->et1mac);

@@ -530,6 +530,12 @@
 		goto err_irq;
 	}
 
+	/* set up multi-rate retry capabilities */
+	if (sc->ah->ah_version == AR5K_AR5212) {
+		hw->max_altrates = 3;
+		hw->max_altrate_tries = 11;
+	}
+
 	/* Finish private driver data initialization */
 	ret = ath5k_attach(pdev, hw);
 	if (ret)

@@ -1149,7 +1155,9 @@
 	struct sk_buff *skb = bf->skb;
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 	unsigned int pktlen, flags, keyidx = AR5K_TXKEYIX_INVALID;
-	int ret;
+	struct ieee80211_rate *rate;
+	unsigned int mrr_rate[3], mrr_tries[3];
+	int i, ret;
 
 	flags = AR5K_TXDESC_INTREQ | AR5K_TXDESC_CLRDMASK;
 

@@ -1174,6 +1182,22 @@
 	if (ret)
 		goto err_unmap;
 
+	memset(mrr_rate, 0, sizeof(mrr_rate));
+	memset(mrr_tries, 0, sizeof(mrr_tries));
+	for (i = 0; i < 3; i++) {
+		rate = ieee80211_get_alt_retry_rate(sc->hw, info, i);
+		if (!rate)
+			break;
+
+		mrr_rate[i] = rate->hw_value;
+		mrr_tries[i] = info->control.retries[i].limit;
+	}
+
+	ah->ah_setup_mrr_tx_desc(ah, ds,
+		mrr_rate[0], mrr_tries[0],
+		mrr_rate[1], mrr_tries[1],
+		mrr_rate[2], mrr_tries[2]);
+
 	ds->ds_link = 0;
 	ds->ds_data = bf->skbaddr;
 

@@ -1790,7 +1814,7 @@
 	struct ath5k_desc *ds;
 	struct sk_buff *skb;
 	struct ieee80211_tx_info *info;
-	int ret;
+	int i, ret;
 
 	spin_lock(&txq->lock);
 	list_for_each_entry_safe(bf, bf0, &txq->q, list) {

@@ -1812,7 +1836,25 @@
 		pci_unmap_single(sc->pdev, bf->skbaddr, skb->len,
 				PCI_DMA_TODEVICE);
 
-		info->status.retry_count = ts.ts_shortretry + ts.ts_longretry / 6;
+		memset(&info->status, 0, sizeof(info->status));
+		info->tx_rate_idx = ath5k_hw_to_driver_rix(sc,
+				ts.ts_rate[ts.ts_final_idx]);
+		info->status.retry_count = ts.ts_longretry;
+
+		for (i = 0; i < 4; i++) {
+			struct ieee80211_tx_altrate *r =
+				&info->status.retries[i];
+
+			if (ts.ts_rate[i]) {
+				r->rate_idx = ath5k_hw_to_driver_rix(sc, ts.ts_rate[i]);
+				r->limit = ts.ts_retry[i];
+			} else {
+				r->rate_idx = -1;
+				r->limit = 0;
+			}
+		}
+
+		info->status.excessive_retries = 0;
 		if (unlikely(ts.ts_status)) {
 			sc->ll_stats.dot11ACKFailureCount++;
 			if (ts.ts_status & AR5K_TXERR_XRETRY)

97 lines not on this page · raw message

@@ -418,7 +418,9 @@
 	u16	ts_seqnum;
 	u16	ts_tstamp;
 	u8	ts_status;
-	u8	ts_rate;
+	u8	ts_rate[4];
+	u8	ts_retry[4];
+	u8	ts_final_idx;
 	s8	ts_rssi;
 	u8	ts_shortretry;
 	u8	ts_longretry;

@@ -0,0 +1,583 @@
+/*
+ * Copyright (C) 2008 Felix Fietkau <[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.
+ *
+ * Based on minstrel.c:
+ *   Copyright (C) 2005-2007 Derek Smithies <[email protected]>
+ *   Sponsored by Indranet Technologies Ltd
+ *
+ * Based on sample.c:
+ *   Copyright (c) 2005 John Bicket
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer,
+ *      without modification.
+ *   2. Redistributions in binary form must reproduce at minimum a disclaimer
+ *      similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
+ *      redistribution must be conditioned upon including a substantially
+ *      similar Disclaimer requirement for further binary redistribution.
+ *   3. Neither the names of the above-listed copyright holders nor the names
+ *      of any contributors may be used to endorse or promote products derived
+ *      from this software without specific prior written permission.
+ *
+ *   Alternatively, this software may be distributed under the terms of the
+ *   GNU General Public License ("GPL") version 2 as published by the Free
+ *   Software Foundation.
+ *
+ *   NO WARRANTY
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
+ *   AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+ *   THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
+ *   OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ *   SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
+ *   IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ *   ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ *   THE POSSIBILITY OF SUCH DAMAGES.
+ */
+#include <linux/netdevice.h>
+#include <linux/types.h>
+#include <linux/skbuff.h>
+#include <linux/debugfs.h>
+#include <linux/random.h>
+#include <linux/ieee80211.h>
+#include <net/mac80211.h>
+#include "rate.h"
+#include "rc80211_minstrel.h"
+
+#define SAMPLE_COLUMNS	10
+#define SAMPLE_TBL(_mi, _idx, _col) \
+		_mi->sample_table[(_idx * SAMPLE_COLUMNS) + _col]
+
+/* convert mac80211 rate index to local array index */
+static inline int
+rix_to_ndx(struct minstrel_sta_info *mi, int rix)
+{
+	int i = rix;
+	for (i = rix; i >= 0; i--)
+		if (mi->r[i].rix == rix)
+			break;
+	WARN_ON(mi->r[i].rix != rix);
+	return i;
+}
+
+static inline bool
+use_low_rate(struct sk_buff *skb)
+{
+	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	u16 fc;
+
+	fc = le16_to_cpu(hdr->frame_control);
+
+	return ((info->flags & IEEE80211_TX_CTL_NO_ACK) ||
+		(fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA ||
+		is_multicast_ether_addr(hdr->addr1));
+}
+
+
+static void
+minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
+{
+	u32 max_tp = 0, index_max_tp = 0, index_max_tp2 = 0;
+	u32 max_prob = 0, index_max_prob = 0;
+	u32 usecs;
+	u32 p;
+	int i;
+
+	mi->stats_update = jiffies;
+	for (i = 0; i < mi->n_rates; i++) {
+		struct minstrel_rate *mr = &mi->r[i];
+
+		usecs = mr->perfect_tx_time;
+		if (!usecs)
+			usecs = 1000000;
+
+		/* To avoid rounding issues, probabilities scale from 0 (0%)
+		 * to 18000 (100%) */
+		if (mr->attempts) {
+			p = (mr->success * 18000) / mr->attempts;
+			mr->succ_hist += mr->success;
+			mr->att_hist += mr->attempts;
+			mr->cur_prob = p;
+			p = ((p * (100 - mp->ewma_level)) + (mr->probability *
+				mp->ewma_level)) / 100;
+			mr->probability = p;
+			mr->cur_tp = p * (1000000 / usecs);
+		}
+
+		mr->last_success = mr->success;
+		mr->last_attempts = mr->attempts;
+		mr->success = 0;
+		mr->attempts = 0;
+
+		/* Sample less often below the 10% chance of success.
+		 * Sample less often above the 95% chance of success. */
+		if ((mr->probability > 17100) || (mr->probability < 1800)) {
+			mr->adjusted_retry_count = mr->retry_count >> 1;
+			if (mr->adjusted_retry_count > 2)
+				mr->adjusted_retry_count = 2;
+		} else {
+			mr->adjusted_retry_count = mr->retry_count;
+		}
+		if (!mr->adjusted_retry_count)
+			mr->adjusted_retry_count = 2;
+	}
+
+	for (i = 0; i < mi->n_rates; i++) {
+		struct minstrel_rate *mr = &mi->r[i];
+		if (max_tp < mr->cur_tp) {
+			index_max_tp = i;
+			max_tp = mr->cur_tp;
+		}
+		if (max_prob < mr->probability) {
+			index_max_prob = i;
+			max_prob = mr->probability;
+		}
+	}
+
+	max_tp = 0;
+	for (i = 0; i < mi->n_rates; i++) {
+		struct minstrel_rate *mr = &mi->r[i];
+
+		if (i == index_max_tp)
+			continue;
+
+		if (max_tp < mr->cur_tp) {
+			index_max_tp2 = i;
+			max_tp = mr->cur_tp;
+		}
+	}
+	mi->max_tp_rate = index_max_tp;
+	mi->max_tp_rate2 = index_max_tp2;
+	mi->max_prob_rate = index_max_prob;
+}
+
+static void
+minstrel_tx_status(void *priv, struct ieee80211_supported_band *sband,
+                   struct ieee80211_sta *sta, void *priv_sta,
+		   struct sk_buff *skb)
+{
+	struct minstrel_sta_info *mi = priv_sta;
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	struct ieee80211_tx_altrate *ar = info->status.retries;
+	struct minstrel_priv *mp = priv;
+	int i, ndx, tries;
+	int success = 0;
+
+	if (!info->status.excessive_retries)
+		success = 1;
+
+	if (!mp->has_mrr || (ar[0].rate_idx < 0)) {
+		ndx = rix_to_ndx(mi, info->tx_rate_idx);
+		tries = info->status.retry_count + 1;
+		mi->r[ndx].success += success;
+		mi->r[ndx].attempts += tries;
+		return;
+	}
+
+	for (i = 0; i < 4; i++) {
+		if (ar[i].rate_idx < 0)
+			break;
+
+		ndx = rix_to_ndx(mi, ar[i].rate_idx);
+		mi->r[ndx].attempts += ar[i].limit + 1;
+
+		if ((i != 3) && (ar[i + 1].rate_idx < 0))
+			mi->r[ndx].success += success;
+	}
+
+	if ((info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) && (i >= 0))
+		mi->sample_count++;
+
+	if (mi->sample_deferred > 0)
+		mi->sample_deferred--;
+}
+
+
+static inline unsigned int
+minstrel_get_retry_count(struct minstrel_rate *mr,
+                         struct ieee80211_tx_info *info)
+{
+	unsigned int retry = mr->adjusted_retry_count;
+
+	if (info->flags & IEEE80211_TX_CTL_USE_RTS_CTS)
+		retry = max(2U, min(mr->retry_count_rtscts, retry));
+	else if (info->flags & IEEE80211_TX_CTL_USE_CTS_PROTECT)
+		retry = max(2U, min(mr->retry_count_cts, retry));
+	return retry;
+}
+
+
+static int
+minstrel_get_next_sample(struct minstrel_sta_info *mi)
+{
+	unsigned int sample_ndx;
+	sample_ndx = SAMPLE_TBL(mi, mi->sample_idx, mi->sample_column);
+	mi->sample_idx++;
+	if (mi->sample_idx > (mi->n_rates - 2)) {
+		mi->sample_idx = 0;
+		mi->sample_column++;
+		if (mi->sample_column >= SAMPLE_COLUMNS)
+			mi->sample_column = 0;
+	}
+	return sample_ndx;
+}
+
+void
+minstrel_get_rate(void *priv, struct ieee80211_supported_band *sband,
+                  struct ieee80211_sta *sta, void *priv_sta,
+                  struct sk_buff *skb, struct rate_selection *sel)
+{
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	struct minstrel_sta_info *mi = priv_sta;
+	struct minstrel_priv *mp = priv;
+	struct ieee80211_tx_altrate *ar = info->control.retries;
+	unsigned int ndx, sample_ndx = 0;
+	bool mrr;
+	bool sample_slower = false;
+	bool sample = false;
+	int i, delta;
+	int mrr_ndx[3];
+	int sample_rate;
+
+	if (!sta || !mi || use_low_rate(skb)) {
+		sel->rate_idx = rate_lowest_index(sband, sta);
+		return;
+	}
+
+	mrr = mp->has_mrr;
+
+	/* mac80211 does not allow mrr for RTS/CTS */
+	if ((info->flags & IEEE80211_TX_CTL_USE_RTS_CTS) ||
+	    (info->flags & IEEE80211_TX_CTL_USE_CTS_PROTECT))
+		mrr = false;
+
+	if (time_after(jiffies, mi->stats_update + (mp->update_interval *
+			HZ) / 1000))
+		minstrel_update_stats(mp, mi);
+
+	ndx = mi->max_tp_rate;
+
+	if (mrr)
+		sample_rate = mp->lookaround_rate_mrr;
+	else
+		sample_rate = mp->lookaround_rate;
+
+	mi->packet_count++;
+	delta = (mi->packet_count * sample_rate / 100) -
+			(mi->sample_count + mi->sample_deferred / 2);
+
+	/* delta > 0: sampling required */
+	if (delta > 0) {
+		if (mi->packet_count >= 10000) {
+			mi->sample_deferred = 0;
+			mi->sample_count = 0;
+			mi->packet_count = 0;
+		} else if (delta > mi->n_rates * 2) {
+			/* With multi-rate retry, not every planned sample
+			 * attempt actually gets used, due to the way the retry
+			 * chain is set up - [max_tp,sample,prob,lowest] for
+			 * sample_rate < max_tp.
+			 *
+			 * If there's too much sampling backlog and the link
+			 * starts getting worse, minstrel would start bursting
+			 * out lots of sampling frames, which would result
+			 * in a large throughput loss. */
+			mi->sample_count += (delta - mi->n_rates * 2);
+		}
+
+		sample_ndx = minstrel_get_next_sample(mi);
+		sample = true;
+		sample_slower = mrr && (mi->r[sample_ndx].perfect_tx_time >
+			mi->r[ndx].perfect_tx_time);
+
+		if (!sample_slower) {
+			ndx = sample_ndx;
+			mi->sample_count++;
+		} else {
+			/* Only use IEEE80211_TX_CTL_RATE_CTRL_PROBE to mark
+			 * packets that have the sampling rate deferred to the
+			 * second MRR stage. Increase the sample counter only
+			 * if the deferred sample rate was actually used.
+			 * Use the sample_deferred counter to make sure that
+			 * the sampling is not done in large bursts */
+			info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
+			mi->sample_deferred++;
+		}
+	}
+	sel->rate_idx = mi->r[ndx].rix;
+	info->control.retry_limit = minstrel_get_retry_count(&mi->r[ndx], info);
+
+	if (!mrr) {
+		ar[0].rate_idx = mi->lowest_rix;
+		ar[0].limit = mp->max_retry;
+		ar[1].rate_idx = -1;
+		return;
+	}
+
+	/* MRR setup */
+	if (sample) {
+		if (sample_slower)
+			mrr_ndx[0] = sample_ndx;
+		else
+			mrr_ndx[0] = mi->max_tp_rate;
+	} else {
+		mrr_ndx[0] = mi->max_tp_rate2;
+	}
+	mrr_ndx[1] = mi->max_prob_rate;
+	mrr_ndx[2] = 0;
+	for (i = 0; i < 3; i++) {
+		ar[i].rate_idx = mi->r[mrr_ndx[i]].rix;
+		ar[i].limit = mi->r[mrr_ndx[i]].adjusted_retry_count;
+	}
+}
+
+
+static void
+calc_rate_durations(struct minstrel_sta_info *mi, struct ieee80211_local *local,
+                    struct minstrel_rate *d, struct ieee80211_rate *rate)
+{
+	int erp = !!(rate->flags & IEEE80211_RATE_ERP_G);
+
+	d->perfect_tx_time = ieee80211_frame_duration(local, 1200,
+			rate->bitrate, erp, 1);
+	d->ack_time = ieee80211_frame_duration(local, 10,
+			rate->bitrate, erp, 1);
+}
+
+static void
+init_sample_table(struct minstrel_sta_info *mi)
+{
+	unsigned int i, col, new_idx;
+	unsigned int n_srates = mi->n_rates - 1;
+	u8 rnd[8];
+
+	mi->sample_column = 0;
+	mi->sample_idx = 0;
+	memset(mi->sample_table, 0, SAMPLE_COLUMNS * mi->n_rates);
+
+	for (col = 0; col < SAMPLE_COLUMNS; col++) {
+		for (i = 0; i < n_srates; i++) {
+			get_random_bytes(rnd, sizeof(rnd));
+			new_idx = (i + rnd[i & 7]) % n_srates;
+
+			while (SAMPLE_TBL(mi, new_idx, col) != 0)
+				new_idx = (new_idx + 1) % n_srates;
+
+			/* Don't sample the slowest rate (i.e. slowest base
+			 * rate). We must presume that the slowest rate works
+			 * fine, or else other management frames will also be
+			 * failing and the link will break */
+			SAMPLE_TBL(mi, new_idx, col) = i + 1;
+		}
+	}
+}
+
+static void
+minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband,
+               struct ieee80211_sta *sta, void *priv_sta)
+{
+	struct minstrel_sta_info *mi = priv_sta;
+	struct minstrel_priv *mp = priv;
+	struct minstrel_rate *mr_ctl;
+	unsigned int i, n = 0;
+	unsigned int t_slot = 9; /* FIXME: get real slot time */
+
+	mi->lowest_rix = rate_lowest_index(sband, sta);
+	mr_ctl = &mi->r[rix_to_ndx(mi, mi->lowest_rix)];
+	mi->sp_ack_dur = mr_ctl->ack_time;
+
+	for (i = 0; i < sband->n_bitrates; i++) {
+		struct minstrel_rate *mr = &mi->r[n];
+		unsigned int tx_time = 0, tx_time_cts = 0, tx_time_rtscts = 0;
+		unsigned int tx_time_single;
+		unsigned int cw = mp->cw_min;
+
+		if (!rate_supported(sta, sband->band, i))
+			continue;
+		n++;
+		memset(mr, 0, sizeof(*mr));
+
+		mr->rix = i;
+		mr->bitrate = sband->bitrates[i].bitrate / 5;
+		calc_rate_durations(mi, hw_to_local(mp->hw), mr,
+				&sband->bitrates[i]);
+
+		/* calculate maximum number of retransmissions before
+		 * fallback (based on maximum segment size) */
+		mr->retry_count = 1;
+		mr->retry_count_cts = 1;
+		mr->retry_count_rtscts = 1;
+		tx_time = mr->perfect_tx_time + mi->sp_ack_dur;
+		do {
+			/* add one retransmission */
+			tx_time_single = mr->ack_time + mr->perfect_tx_time;
+
+			/* contention window */
+			tx_time_single += t_slot + min(cw, mp->cw_max);
+			cw = (cw + 1) << 1;
+
+			tx_time += tx_time_single;
+			tx_time_cts += tx_time_single + mi->sp_ack_dur;
+			tx_time_rtscts += tx_time_single + 2 * mi->sp_ack_dur;
+			if ((tx_time_cts < mp->segment_size) &&
+				(mr->retry_count_cts < mp->max_retry))
+				mr->retry_count_cts++;
+			if ((tx_time_rtscts < mp->segment_size) &&
+				(mr->retry_count_rtscts < mp->max_retry))
+				mr->retry_count_rtscts++;
+		} while ((tx_time < mp->segment_size) &&
+				(++mr->retry_count < mp->max_retry));
+		mr->adjusted_retry_count = mr->retry_count;
+	}
+
+	for (i = n; i < sband->n_bitrates; i++) {
+		struct minstrel_rate *mr = &mi->r[i];
+		mr->rix = -1;
+	}
+
+	mi->n_rates = n;
+	mi->stats_update = jiffies;
+
+	init_sample_table(mi);
+}
+
+static void *
+minstrel_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
+{
+	struct ieee80211_supported_band *sband;
+	struct minstrel_sta_info *mi;
+	struct minstrel_priv *mp = priv;
+	struct ieee80211_hw *hw = mp->hw;
+	int max_rates = 0;
+	int i;
+
+	mi = kzalloc(sizeof(struct minstrel_sta_info), gfp);
+	if (!mi)
+		return NULL;
+
+	for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
+		sband = hw->wiphy->bands[hw->conf.channel->band];
+		if (sband->n_bitrates > max_rates)
+			max_rates = sband->n_bitrates;
+	}
+
+	mi->r = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
+	if (!mi->r)
+		goto error;
+
+	mi->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
+	if (!mi->sample_table)
+		goto error1;
+
+	mi->stats_update = jiffies;
+	return mi;
+
+error1:
+	kfree(mi->r);
+error:
+	kfree(mi);
+	return NULL;
+}
+
+static void
+minstrel_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
+{
+	struct minstrel_sta_info *mi = priv_sta;
+
+	kfree(mi->sample_table);
+	kfree(mi->r);
+	kfree(mi);
+}
+
+static void
+minstrel_clear(void *priv)
+{
+}
+
+static void *
+minstrel_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
+{
+	struct minstrel_priv *mp;
+
+	mp = kzalloc(sizeof(struct minstrel_priv), GFP_ATOMIC);
+	if (!mp)
+		return NULL;
+
+	/* contention window settings
+	 * Just an approximation. Using the per-queue values would complicate
+	 * the calculations and is probably unnecessary */
+	mp->cw_min = 15;
+	mp->cw_max = 1023;
+
+	/* number of packets (in %) to use for sampling other rates
+	 * sample less often for non-mrr packets, because the overhead
+	 * is much higher than with mrr */
+	mp->lookaround_rate = 5;
+	mp->lookaround_rate_mrr = 10;
+
+	/* moving average weight for EWMA */
+	mp->ewma_level = 75;
+
+	/* maximum time that the hw is allowed to stay in one MRR segment */
+	mp->segment_size = 6000;
+
+	if (hw->max_altrate_tries > 0)
+		mp->max_retry = hw->max_altrate_tries;
+	else
+		/* safe default, does not necessarily have to match hw properties */
+		mp->max_retry = 7;
+
+	if (hw->max_altrates >= 3)
+		mp->has_mrr = true;
+
+	mp->hw = hw;
+	mp->update_interval = 100;
+
+	return mp;
+}
+
+static void
+minstrel_free(void *priv)
+{
+	kfree(priv);
+}
+
+static struct rate_control_ops mac80211_minstrel = {
+	.name = "minstrel",
+	.tx_status = minstrel_tx_status,
+	.get_rate = minstrel_get_rate,
+	.rate_init = minstrel_rate_init,
+	.clear = minstrel_clear,
+	.alloc = minstrel_alloc,
+	.free = minstrel_free,
+	.alloc_sta = minstrel_alloc_sta,
+	.free_sta = minstrel_free_sta,
+#ifdef CONFIG_MAC80211_DEBUGFS
+	.add_sta_debugfs = minstrel_add_sta_debugfs,
+	.remove_sta_debugfs = minstrel_remove_sta_debugfs,
+#endif
+};
+
+int __init
+rc80211_minstrel_init(void)
+{
+	return ieee80211_rate_control_register(&mac80211_minstrel);
+}
+
+void
+rc80211_minstrel_exit(void)
+{
+	ieee80211_rate_control_unregister(&mac80211_minstrel);
+}
+

@@ -1015,6 +1015,10 @@
 	BUILD_BUG_ON(offsetof(struct ieee80211_tx_info, driver_data) +
 	             IEEE80211_TX_INFO_DRIVER_DATA_SIZE > sizeof(skb->cb));
 
+	ret = rc80211_minstrel_init();
+	if (ret)
+		return ret;
+
 	ret = rc80211_pid_init();
 	if (ret)
 		return ret;

@@ -1027,6 +1031,7 @@
 static void __exit ieee80211_exit(void)
 {
 	rc80211_pid_exit();
+	rc80211_minstrel_exit();
 
 	/*
 	 * For key todo, it'll be empty by now but the work

@@ -125,4 +125,18 @@
 }
 #endif
 
+#ifdef CONFIG_MAC80211_RC_MINSTREL
+extern int rc80211_minstrel_init(void);
+extern void rc80211_minstrel_exit(void);
+#else
+static inline int rc80211_minstrel_init(void)
+{
+	return 0;
+}
+static inline void rc80211_minstrel_exit(void)
+{
+}
+#endif
+
+
 #endif /* IEEE80211_RATE_H */

85 lines not on this page · raw message

164 lines not on this page · raw message