* [PATCH] mac80211: add the minstrel_ht rate control algorithm
@ 2010-05-13 14:48 Felix Fietkau
0 siblings, 0 replies; only message in thread
From: Felix Fietkau @ 2010-05-13 14:48 UTC (permalink / raw)
To: linux-wireless
Cc: Derek Smithies, Benoit PAPILLAULT, Luis R. Rodriguez,
Christian Lamparter, Björn Smedman, Bob Copeland,
Johannes Berg
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
changes since rfc v3:
- various fixes by christian lamparter
- tune sampling for better aggregation length
- added kconfig option
- enables 3 streams (ath9k supports it now)
--- a/net/mac80211/Makefile
+++ b/net/mac80211/Makefile
@@ -50,7 +50,11 @@ rc80211_pid-$(CONFIG_MAC80211_DEBUGFS) +
rc80211_minstrel-y := rc80211_minstrel.o
rc80211_minstrel-$(CONFIG_MAC80211_DEBUGFS) += rc80211_minstrel_debugfs.o
+rc80211_minstrel_ht-y := rc80211_minstrel_ht.o
+rc80211_minstrel_ht-$(CONFIG_MAC80211_DEBUGFS) += rc80211_minstrel_ht_debugfs.o
+
mac80211-$(CONFIG_MAC80211_RC_PID) += $(rc80211_pid-y)
mac80211-$(CONFIG_MAC80211_RC_MINSTREL) += $(rc80211_minstrel-y)
+mac80211-$(CONFIG_MAC80211_RC_MINSTREL_HT) += $(rc80211_minstrel_ht-y)
ccflags-y += -D__CHECK_ENDIAN__
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -716,6 +716,10 @@ static int __init ieee80211_init(void)
if (ret)
return ret;
+ ret = rc80211_minstrel_ht_init();
+ if (ret)
+ goto err_minstrel;
+
ret = rc80211_pid_init();
if (ret)
goto err_pid;
@@ -728,6 +732,8 @@ static int __init ieee80211_init(void)
err_netdev:
rc80211_pid_exit();
err_pid:
+ rc80211_minstrel_ht_exit();
+ err_minstrel:
rc80211_minstrel_exit();
return ret;
@@ -736,6 +742,7 @@ static int __init ieee80211_init(void)
static void __exit ieee80211_exit(void)
{
rc80211_pid_exit();
+ rc80211_minstrel_ht_exit();
rc80211_minstrel_exit();
/*
--- a/net/mac80211/rate.h
+++ b/net/mac80211/rate.h
@@ -147,5 +147,18 @@ static inline void rc80211_minstrel_exit
}
#endif
+#ifdef CONFIG_MAC80211_RC_MINSTREL_HT
+extern int rc80211_minstrel_ht_init(void);
+extern void rc80211_minstrel_ht_exit(void);
+#else
+static inline int rc80211_minstrel_ht_init(void)
+{
+ return 0;
+}
+static inline void rc80211_minstrel_ht_exit(void)
+{
+}
+#endif
+
#endif /* IEEE80211_RATE_H */
--- /dev/null
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -0,0 +1,824 @@
+/*
+ * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
+ *
+ * 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 <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"
+#include "rc80211_minstrel_ht.h"
+
+#define AVG_PKT_SIZE 1200
+#define SAMPLE_COLUMNS 10
+#define EWMA_LEVEL 75
+
+/* Number of bits for an average sized packet */
+#define MCS_NBITS (AVG_PKT_SIZE << 3)
+
+/* Number of symbols for a packet with (bps) bits per symbol */
+#define MCS_NSYMS(bps) ((MCS_NBITS + (bps) - 1) / (bps))
+
+/* Transmission time for a packet containing (syms) symbols */
+#define MCS_SYMBOL_TIME(sgi, syms) \
+ (sgi ? \
+ ((syms) * 18 + 4) / 5 : /* syms * 3.6 us */ \
+ (syms) << 2 /* syms * 4 us */ \
+ )
+
+/* Transmit duration for the raw data part of an average sized packet */
+#define MCS_DURATION(streams, sgi, bps) MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps)))
+
+/* MCS rate information for an MCS group */
+#define MCS_GROUP(_streams, _sgi, _ht40) { \
+ .streams = _streams, \
+ .flags = \
+ (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
+ (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \
+ .duration = { \
+ MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26), \
+ MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52), \
+ MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78), \
+ MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104), \
+ MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156), \
+ MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208), \
+ MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234), \
+ MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) \
+ } \
+}
+
+/*
+ * To enable sufficiently targeted rate sampling, MCS rates are divided into
+ * groups, based on the number of streams and flags (HT40, SGI) that they
+ * use.
+ */
+const struct mcs_group minstrel_mcs_groups[] = {
+ MCS_GROUP(1, 0, 0),
+ MCS_GROUP(2, 0, 0),
+#if MINSTREL_MAX_STREAMS >= 3
+ MCS_GROUP(3, 0, 0),
+#endif
+
+ MCS_GROUP(1, 1, 0),
+ MCS_GROUP(2, 1, 0),
+#if MINSTREL_MAX_STREAMS >= 3
+ MCS_GROUP(3, 1, 0),
+#endif
+
+ MCS_GROUP(1, 0, 1),
+ MCS_GROUP(2, 0, 1),
+#if MINSTREL_MAX_STREAMS >= 3
+ MCS_GROUP(3, 0, 1),
+#endif
+
+ MCS_GROUP(1, 1, 1),
+ MCS_GROUP(2, 1, 1),
+#if MINSTREL_MAX_STREAMS >= 3
+ MCS_GROUP(3, 1, 1),
+#endif
+};
+
+static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES];
+
+/*
+ * Perform EWMA (Exponentially Weighted Moving Average) calculation
+ */
+static int
+minstrel_ewma(int old, int new, int weight)
+{
+ return (new * (100 - weight) + old * weight) / 100;
+}
+
+/*
+ * Look up an MCS group index based on mac80211 rate information
+ */
+static int
+minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
+{
+ int streams = (rate->idx / MCS_GROUP_RATES) + 1;
+ u32 flags = IEEE80211_TX_RC_SHORT_GI | IEEE80211_TX_RC_40_MHZ_WIDTH;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(minstrel_mcs_groups); i++) {
+ if (minstrel_mcs_groups[i].streams != streams)
+ continue;
+ if (minstrel_mcs_groups[i].flags != (rate->flags & flags))
+ continue;
+
+ return i;
+ }
+
+ WARN_ON(1);
+ return 0;
+}
+
+static inline struct minstrel_rate_stats *
+minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
+{
+ return &mi->groups[index / MCS_GROUP_RATES].rates[index % MCS_GROUP_RATES];
+}
+
+
+/*
+ * Recalculate success probabilities and counters for a rate using EWMA
+ */
+static void
+minstrel_calc_rate_ewma(struct minstrel_priv *mp, struct minstrel_rate_stats *mr)
+{
+ if (unlikely(mr->attempts > 0)) {
+ mr->sample_skipped = 0;
+ mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts);
+ if (!mr->att_hist)
+ mr->probability = mr->cur_prob;
+ else
+ mr->probability = minstrel_ewma(mr->probability,
+ mr->cur_prob, EWMA_LEVEL);
+ mr->att_hist += mr->attempts;
+ mr->succ_hist += mr->success;
+ } else {
+ mr->sample_skipped++;
+ }
+ mr->last_success = mr->success;
+ mr->last_attempts = mr->attempts;
+ mr->success = 0;
+ mr->attempts = 0;
+}
+
+/*
+ * Calculate throughput based on the average A-MPDU length, taking into account
+ * the expected number of retransmissions and their expected length
+ */
+static void
+minstrel_ht_calc_tp(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
+ int group, int rate)
+{
+ struct minstrel_rate_stats *mr;
+ unsigned int usecs;
+
+ mr = &mi->groups[group].rates[rate];
+
+ if (mr->probability < MINSTREL_FRAC(1, 10)) {
+ mr->cur_tp = 0;
+ return;
+ }
+
+ usecs = mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
+ usecs += minstrel_mcs_groups[group].duration[rate];
+ mr->cur_tp = MINSTREL_TRUNC((1000000 / usecs) * mr->probability);
+}
+
+/*
+ * Update rate statistics and select new primary rates
+ *
+ * Rules for rate selection:
+ * - max_prob_rate must use only one stream, as a tradeoff between delivery
+ * probability and throughput during strong fluctuations
+ * - as long as the max prob rate has a probability of more than 3/4, pick
+ * higher throughput rates, even if the probablity is a bit lower
+ */
+static void
+minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
+{
+ struct minstrel_mcs_group_data *mg;
+ struct minstrel_rate_stats *mr;
+ int cur_prob, cur_prob_tp, cur_tp, cur_tp2;
+ int group, i, index;
+
+ if (mi->ampdu_packets > 0) {
+ mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
+ MINSTREL_FRAC(mi->ampdu_len, mi->ampdu_packets), EWMA_LEVEL);
+ mi->ampdu_len = 0;
+ mi->ampdu_packets = 0;
+ }
+
+ mi->sample_slow = 0;
+ mi->sample_count = 0;
+ mi->max_tp_rate = 0;
+ mi->max_tp_rate2 = 0;
+ mi->max_prob_rate = 0;
+
+ for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
+ cur_prob = 0;
+ cur_prob_tp = 0;
+ cur_tp = 0;
+ cur_tp2 = 0;
+
+ mg = &mi->groups[group];
+ if (!mg->supported)
+ continue;
+
+ mg->max_tp_rate = 0;
+ mg->max_tp_rate2 = 0;
+ mg->max_prob_rate = 0;
+ mi->sample_count++;
+
+ for (i = 0; i < MCS_GROUP_RATES; i++) {
+ if (!(mg->supported & BIT(i)))
+ continue;
+
+ mr = &mg->rates[i];
+ mr->retry_updated = false;
+ index = MCS_GROUP_RATES * group + i;
+ minstrel_calc_rate_ewma(mp, mr);
+ minstrel_ht_calc_tp(mp, mi, group, i);
+
+ if (!mr->cur_tp)
+ continue;
+
+ /* ignore the lowest rate of each single-stream group */
+ if (!i && minstrel_mcs_groups[group].streams == 1)
+ continue;
+
+ if ((mr->cur_tp > cur_prob_tp && mr->probability >
+ MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
+ mg->max_prob_rate = index;
+ cur_prob = mr->probability;
+ }
+
+ if (mr->cur_tp > cur_tp) {
+ swap(index, mg->max_tp_rate);
+ cur_tp = mr->cur_tp;
+ mr = minstrel_get_ratestats(mi, index);
+ }
+
+ if (index >= mg->max_tp_rate)
+ continue;
+
+ if (mr->cur_tp > cur_tp2) {
+ mg->max_tp_rate2 = index;
+ cur_tp2 = mr->cur_tp;
+ }
+ }
+ }
+
+ /* try to sample up to half of the availble rates during each interval */
+ mi->sample_count *= 4;
+
+ cur_prob = 0;
+ cur_prob_tp = 0;
+ cur_tp = 0;
+ cur_tp2 = 0;
+ for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
+ mg = &mi->groups[group];
+ if (!mg->supported)
+ continue;
+
+ mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
+ if (cur_prob_tp < mr->cur_tp &&
+ minstrel_mcs_groups[group].streams == 1) {
+ mi->max_prob_rate = mg->max_prob_rate;
+ cur_prob = mr->cur_prob;
+ }
+
+ mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
+ if (cur_tp < mr->cur_tp) {
+ mi->max_tp_rate = mg->max_tp_rate;
+ cur_tp = mr->cur_tp;
+ }
+
+ mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
+ if (cur_tp2 < mr->cur_tp) {
+ mi->max_tp_rate2 = mg->max_tp_rate2;
+ cur_tp2 = mr->cur_tp;
+ }
+ }
+
+ mi->stats_update = jiffies;
+}
+
+static bool
+minstrel_ht_txstat_valid(struct ieee80211_tx_rate *rate)
+{
+ if (!rate->count)
+ return false;
+
+ if (rate->idx < 0)
+ return false;
+
+ return !!(rate->flags & IEEE80211_TX_RC_MCS);
+}
+
+static void
+minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
+{
+ struct minstrel_mcs_group_data *mg;
+
+ for (;;) {
+ mi->sample_group++;
+ mi->sample_group %= ARRAY_SIZE(minstrel_mcs_groups);
+ mg = &mi->groups[mi->sample_group];
+
+ if (!mg->supported)
+ continue;
+
+ if (++mg->index >= MCS_GROUP_RATES) {
+ mg->index = 0;
+ if (++mg->column >= ARRAY_SIZE(sample_table))
+ mg->column = 0;
+ }
+ break;
+ }
+}
+
+static void
+minstrel_downgrade_rate(struct minstrel_ht_sta *mi, int *idx, bool primary)
+{
+ int group, orig_group;
+
+ orig_group = group = *idx / MCS_GROUP_RATES;
+ while (group > 0) {
+ group--;
+
+ if (!mi->groups[group].supported)
+ continue;
+
+ if (minstrel_mcs_groups[group].streams >
+ minstrel_mcs_groups[orig_group].streams)
+ continue;
+
+ if (primary)
+ *idx = mi->groups[group].max_tp_rate;
+ else
+ *idx = mi->groups[group].max_tp_rate2;
+ break;
+ }
+}
+
+static void
+minstrel_aggr_check(struct minstrel_priv *mp, struct ieee80211_sta *pubsta, struct sk_buff *skb)
+{
+ struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+ struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
+ u16 tid;
+
+ if (unlikely(!ieee80211_is_data_qos(hdr->frame_control)))
+ return;
+
+ if (unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)))
+ return;
+
+ tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
+ if (likely(sta->ampdu_mlme.tid_state_tx[tid] != HT_AGG_STATE_IDLE))
+ return;
+
+ ieee80211_start_tx_ba_session(pubsta, tid);
+}
+
+static void
+minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
+ struct ieee80211_sta *sta, void *priv_sta,
+ struct sk_buff *skb)
+{
+ struct minstrel_ht_sta_priv *msp = priv_sta;
+ struct minstrel_ht_sta *mi = &msp->ht;
+ struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+ struct ieee80211_tx_rate *ar = info->status.rates;
+ struct minstrel_rate_stats *rate, *rate2;
+ struct minstrel_priv *mp = priv;
+ bool last = false;
+ int group;
+ int i = 0;
+
+ if (!msp->is_ht)
+ return mac80211_minstrel.tx_status(priv, sband, sta, &msp->legacy, skb);
+
+ /* This packet was aggregated but doesn't carry status info */
+ if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
+ !(info->flags & IEEE80211_TX_STAT_AMPDU))
+ return;
+
+ if (!info->status.ampdu_len) {
+ info->status.ampdu_ack_len = 1;
+ info->status.ampdu_len = 1;
+ }
+
+ mi->ampdu_packets++;
+ mi->ampdu_len += info->status.ampdu_len;
+
+ if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
+ mi->sample_wait = 4 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
+ mi->sample_tries = 3;
+ mi->sample_count--;
+ }
+
+ if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) {
+ mi->sample_packets += info->status.ampdu_len;
+ minstrel_next_sample_idx(mi);
+ }
+
+ for (i = 0; !last; i++) {
+ last = (i == IEEE80211_TX_MAX_RATES - 1) ||
+ !minstrel_ht_txstat_valid(&ar[i + 1]);
+
+ if (!minstrel_ht_txstat_valid(&ar[i]))
+ break;
+
+ group = minstrel_ht_get_group_idx(&ar[i]);
+ rate = &mi->groups[group].rates[ar[i].idx % 8];
+
+ if (last && (info->flags & IEEE80211_TX_STAT_ACK))
+ rate->success += info->status.ampdu_ack_len;
+
+ rate->attempts += ar[i].count * info->status.ampdu_len;
+ }
+
+ /*
+ * check for sudden death of spatial multiplexing,
+ * downgrade to a lower number of streams if necessary.
+ */
+ rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
+ if (rate->attempts > 30 &&
+ MINSTREL_FRAC(rate->success, rate->attempts) <
+ MINSTREL_FRAC(20, 100))
+ minstrel_downgrade_rate(mi, &mi->max_tp_rate, true);
+
+ rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
+ if (rate->attempts > 30 &&
+ MINSTREL_FRAC(rate->success, rate->attempts) <
+ MINSTREL_FRAC(20, 100))
+ minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false);
+
+ if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {
+ minstrel_ht_update_stats(mp, mi);
+ minstrel_aggr_check(mp, sta, skb);
+ }
+}
+
+static void
+minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
+ int index)
+{
+ struct minstrel_rate_stats *mr;
+ const struct mcs_group *group;
+ unsigned int tx_time, tx_time_rtscts, tx_time_data;
+ unsigned int cw = mp->cw_min;
+ unsigned int t_slot = 9; /* FIXME */
+ unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
+
+ mr = minstrel_get_ratestats(mi, index);
+ if (mr->probability < MINSTREL_FRAC(1, 10)) {
+ mr->retry_count = 1;
+ mr->retry_count_rtscts = 1;
+ return;
+ }
+
+ mr->retry_count = 2;
+ mr->retry_count_rtscts = 2;
+ mr->retry_updated = true;
+
+ group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
+ tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len;
+ tx_time = 2 * (t_slot + mi->overhead + tx_time_data);
+ tx_time_rtscts = 2 * (t_slot + mi->overhead_rtscts + tx_time_data);
+ do {
+ cw = (cw << 1) | 1;
+ cw = min(cw, mp->cw_max);
+ tx_time += cw + t_slot + mi->overhead;
+ tx_time_rtscts += cw + t_slot + mi->overhead_rtscts;
+ if (tx_time_rtscts < mp->segment_size)
+ mr->retry_count_rtscts++;
+ } while ((tx_time < mp->segment_size) &&
+ (++mr->retry_count < mp->max_retry));
+}
+
+
+static void
+minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
+ struct ieee80211_tx_rate *rate, int index,
+ struct ieee80211_tx_rate_control *txrc,
+ bool sample, bool rtscts)
+{
+ const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
+ struct minstrel_rate_stats *mr;
+
+ mr = minstrel_get_ratestats(mi, index);
+ if (!mr->retry_updated)
+ minstrel_calc_retransmit(mp, mi, index);
+
+ if (mr->probability < MINSTREL_FRAC(20, 100))
+ rate->count = 2;
+ else if (rtscts)
+ rate->count = mr->retry_count_rtscts;
+ else
+ rate->count = mr->retry_count;
+
+ rate->flags = IEEE80211_TX_RC_MCS | group->flags;
+ if (txrc->short_preamble)
+ rate->flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
+ if (txrc->rts || rtscts)
+ rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS;
+ rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES;
+}
+
+static inline int
+minstrel_get_duration(int index)
+{
+ const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
+ return group->duration[index % MCS_GROUP_RATES];
+}
+
+static int
+minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
+{
+ struct minstrel_rate_stats *mr;
+ struct minstrel_mcs_group_data *mg;
+ int sample_idx = 0;
+
+ if (mi->sample_wait > 0) {
+ mi->sample_wait--;
+ return -1;
+ }
+
+ if (!mi->sample_tries)
+ return -1;
+
+ mi->sample_tries--;
+ mg = &mi->groups[mi->sample_group];
+ sample_idx = sample_table[mg->column][mg->index];
+ mr = &mg->rates[sample_idx];
+ sample_idx += mi->sample_group * MCS_GROUP_RATES;
+
+ /*
+ * When not using MRR, do not sample if the probability is already
+ * higher than 95% to avoid wasting airtime
+ */
+ if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100)))
+ goto next;
+
+ /*
+ * Make sure that lower rates get sampled only occasionally,
+ * if the link is working perfectly.
+ */
+ if (minstrel_get_duration(sample_idx) >
+ minstrel_get_duration(mi->max_tp_rate)) {
+ if (mr->sample_skipped < 10)
+ goto next;
+
+ if (mi->sample_slow++ > 2)
+ goto next;
+ }
+
+ return sample_idx;
+
+next:
+ minstrel_next_sample_idx(mi);
+ return -1;
+}
+
+static void
+minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
+ struct ieee80211_tx_rate_control *txrc)
+{
+ struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
+ struct ieee80211_tx_rate *ar = info->status.rates;
+ struct minstrel_ht_sta_priv *msp = priv_sta;
+ struct minstrel_ht_sta *mi = &msp->ht;
+ struct minstrel_priv *mp = priv;
+ int sample_idx;
+
+ if (rate_control_send_low(sta, priv_sta, txrc))
+ return;
+
+ if (!msp->is_ht)
+ return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);
+
+ info->flags |= mi->tx_flags;
+ sample_idx = minstrel_get_sample_rate(mp, mi);
+ if (sample_idx >= 0) {
+ minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx,
+ txrc, true, false);
+ minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate,
+ txrc, false, true);
+ info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
+ } else {
+ minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate,
+ txrc, false, false);
+ minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2,
+ txrc, false, true);
+ }
+ minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, txrc, false, true);
+
+ ar[3].count = 0;
+ ar[3].idx = -1;
+
+ mi->total_packets++;
+
+ /* wraparound */
+ if (mi->total_packets == ~0) {
+ mi->total_packets = 0;
+ mi->sample_packets = 0;
+ }
+}
+
+static void
+minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
+ struct ieee80211_sta *sta, void *priv_sta,
+ enum nl80211_channel_type oper_chan_type)
+{
+ struct minstrel_priv *mp = priv;
+ struct minstrel_ht_sta_priv *msp = priv_sta;
+ struct minstrel_ht_sta *mi = &msp->ht;
+ struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
+ struct ieee80211_local *local = hw_to_local(mp->hw);
+ u16 sta_cap = sta->ht_cap.cap;
+ int ack_dur;
+ int stbc;
+ int i;
+
+ /* fall back to the old minstrel for legacy stations */
+ if (sta && !sta->ht_cap.ht_supported) {
+ msp->is_ht = false;
+ memset(&msp->legacy, 0, sizeof(msp->legacy));
+ msp->legacy.r = msp->ratelist;
+ msp->legacy.sample_table = msp->sample_table;
+ return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy);
+ }
+
+ BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
+ MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS);
+
+ msp->is_ht = true;
+ memset(mi, 0, sizeof(*mi));
+ mi->stats_update = jiffies;
+
+ ack_dur = ieee80211_frame_duration(local, 10, 60, 1, 1);
+ mi->overhead = ieee80211_frame_duration(local, 0, 60, 1, 1) + ack_dur;
+ mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
+
+ mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
+
+ /* When using MRR, sample more on the first attempt, without delay */
+ if (mp->has_mrr) {
+ mi->sample_count = 16;
+ mi->sample_wait = 0;
+ } else {
+ mi->sample_count = 8;
+ mi->sample_wait = 8;
+ }
+ mi->sample_tries = 4;
+
+ stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
+ IEEE80211_HT_CAP_RX_STBC_SHIFT;
+ mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
+
+ if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
+ mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
+
+ if (oper_chan_type != NL80211_CHAN_HT40MINUS &&
+ oper_chan_type != NL80211_CHAN_HT40PLUS)
+ sta_cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
+
+ for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
+ u16 req = 0;
+
+ mi->groups[i].supported = 0;
+ if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {
+ if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
+ req |= IEEE80211_HT_CAP_SGI_40;
+ else
+ req |= IEEE80211_HT_CAP_SGI_20;
+ }
+
+ if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
+ req |= IEEE80211_HT_CAP_SUP_WIDTH_20_40;
+
+ if ((sta_cap & req) != req)
+ continue;
+
+ mi->groups[i].supported =
+ mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
+ }
+}
+
+static void
+minstrel_ht_rate_init(void *priv, struct ieee80211_supported_band *sband,
+ struct ieee80211_sta *sta, void *priv_sta)
+{
+ struct minstrel_priv *mp = priv;
+
+ minstrel_ht_update_caps(priv, sband, sta, priv_sta, mp->hw->conf.channel_type);
+}
+
+static void
+minstrel_ht_rate_update(void *priv, struct ieee80211_supported_band *sband,
+ struct ieee80211_sta *sta, void *priv_sta,
+ u32 changed, enum nl80211_channel_type oper_chan_type)
+{
+ minstrel_ht_update_caps(priv, sband, sta, priv_sta, oper_chan_type);
+}
+
+static void *
+minstrel_ht_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp)
+{
+ struct ieee80211_supported_band *sband;
+ struct minstrel_ht_sta_priv *msp;
+ struct minstrel_priv *mp = priv;
+ struct ieee80211_hw *hw = mp->hw;
+ int max_rates = 0;
+ int i;
+
+ for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
+ sband = hw->wiphy->bands[i];
+ if (sband && sband->n_bitrates > max_rates)
+ max_rates = sband->n_bitrates;
+ }
+
+ msp = kzalloc(sizeof(struct minstrel_ht_sta), gfp);
+ if (!msp)
+ return NULL;
+
+ msp->ratelist = kzalloc(sizeof(struct minstrel_rate) * max_rates, gfp);
+ if (!msp->ratelist)
+ goto error;
+
+ msp->sample_table = kmalloc(SAMPLE_COLUMNS * max_rates, gfp);
+ if (!msp->sample_table)
+ goto error1;
+
+ return msp;
+
+error1:
+ kfree(msp->sample_table);
+error:
+ kfree(msp);
+ return NULL;
+}
+
+static void
+minstrel_ht_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta)
+{
+ struct minstrel_ht_sta_priv *msp = priv_sta;
+
+ kfree(msp->sample_table);
+ kfree(msp->ratelist);
+ kfree(msp);
+}
+
+static void *
+minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
+{
+ return mac80211_minstrel.alloc(hw, debugfsdir);
+}
+
+static void
+minstrel_ht_free(void *priv)
+{
+ mac80211_minstrel.free(priv);
+}
+
+static struct rate_control_ops mac80211_minstrel_ht = {
+ .name = "minstrel_ht",
+ .tx_status = minstrel_ht_tx_status,
+ .get_rate = minstrel_ht_get_rate,
+ .rate_init = minstrel_ht_rate_init,
+ .rate_update = minstrel_ht_rate_update,
+ .alloc_sta = minstrel_ht_alloc_sta,
+ .free_sta = minstrel_ht_free_sta,
+ .alloc = minstrel_ht_alloc,
+ .free = minstrel_ht_free,
+#ifdef CONFIG_MAC80211_DEBUGFS
+ .add_sta_debugfs = minstrel_ht_add_sta_debugfs,
+ .remove_sta_debugfs = minstrel_ht_remove_sta_debugfs,
+#endif
+};
+
+
+static void
+init_sample_table(void)
+{
+ int col, i, new_idx;
+ u8 rnd[MCS_GROUP_RATES];
+
+ memset(sample_table, 0xff, sizeof(sample_table));
+ for (col = 0; col < SAMPLE_COLUMNS; col++) {
+ for (i = 0; i < MCS_GROUP_RATES; i++) {
+ get_random_bytes(rnd, sizeof(rnd));
+ new_idx = (i + rnd[i]) % MCS_GROUP_RATES;
+
+ while (sample_table[col][new_idx] != 0xff)
+ new_idx = (new_idx + 1) % MCS_GROUP_RATES;
+
+ sample_table[col][new_idx] = i;
+ }
+ }
+}
+
+int __init
+rc80211_minstrel_ht_init(void)
+{
+ init_sample_table();
+ return ieee80211_rate_control_register(&mac80211_minstrel_ht);
+}
+
+void
+rc80211_minstrel_ht_exit(void)
+{
+ ieee80211_rate_control_unregister(&mac80211_minstrel_ht);
+}
--- /dev/null
+++ b/net/mac80211/rc80211_minstrel_ht.h
@@ -0,0 +1,128 @@
+/*
+ * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
+ *
+ * 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 __RC_MINSTREL_HT_H
+#define __RC_MINSTREL_HT_H
+
+/*
+ * The number of streams can be changed to 2 to reduce code
+ * size and memory footprint.
+ */
+#define MINSTREL_MAX_STREAMS 3
+#define MINSTREL_STREAM_GROUPS 4
+
+/* scaled fraction values */
+#define MINSTREL_SCALE 16
+#define MINSTREL_FRAC(val, div) (((val) << MINSTREL_SCALE) / div)
+#define MINSTREL_TRUNC(val) ((val) >> MINSTREL_SCALE)
+
+#define MCS_GROUP_RATES 8
+
+struct mcs_group {
+ u32 flags;
+ unsigned int streams;
+ unsigned int duration[MCS_GROUP_RATES];
+};
+
+struct minstrel_rate_stats {
+ /* current / last sampling period attempts/success counters */
+ unsigned int attempts, last_attempts;
+ unsigned int success, last_success;
+
+ /* total attempts/success counters */
+ u64 att_hist, succ_hist;
+
+ /* current throughput */
+ unsigned int cur_tp;
+
+ /* packet delivery probabilities */
+ unsigned int cur_prob, probability;
+
+ /* maximum retry counts */
+ unsigned int retry_count;
+ unsigned int retry_count_rtscts;
+
+ bool retry_updated;
+ u8 sample_skipped;
+};
+
+struct minstrel_mcs_group_data {
+ u8 index;
+ u8 column;
+
+ /* bitfield of supported MCS rates of this group */
+ u8 supported;
+
+ /* selected primary rates */
+ unsigned int max_tp_rate;
+ unsigned int max_tp_rate2;
+ unsigned int max_prob_rate;
+
+ /* MCS rate statistics */
+ struct minstrel_rate_stats rates[MCS_GROUP_RATES];
+};
+
+struct minstrel_ht_sta {
+ /* ampdu length (average, per sampling interval) */
+ unsigned int ampdu_len;
+ unsigned int ampdu_packets;
+
+ /* ampdu length (EWMA) */
+ unsigned int avg_ampdu_len;
+
+ /* best throughput rate */
+ unsigned int max_tp_rate;
+
+ /* second best throughput rate */
+ unsigned int max_tp_rate2;
+
+ /* best probability rate */
+ unsigned int max_prob_rate;
+
+ /* time of last status update */
+ unsigned long stats_update;
+
+ /* overhead time in usec for each frame */
+ unsigned int overhead;
+ unsigned int overhead_rtscts;
+
+ unsigned int total_packets;
+ unsigned int sample_packets;
+
+ /* tx flags to add for frames for this sta */
+ u32 tx_flags;
+
+ u8 sample_wait;
+ u8 sample_tries;
+ u8 sample_count;
+ u8 sample_slow;
+
+ /* current MCS group to be sampled */
+ u8 sample_group;
+
+ /* MCS rate group info and statistics */
+ struct minstrel_mcs_group_data groups[MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS];
+};
+
+struct minstrel_ht_sta_priv {
+ union {
+ struct minstrel_ht_sta ht;
+ struct minstrel_sta_info legacy;
+ };
+#ifdef CONFIG_MAC80211_DEBUGFS
+ struct dentry *dbg_stats;
+#endif
+ void *ratelist;
+ void *sample_table;
+ bool is_ht;
+};
+
+void minstrel_ht_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir);
+void minstrel_ht_remove_sta_debugfs(void *priv, void *priv_sta);
+
+#endif
--- /dev/null
+++ b/net/mac80211/rc80211_minstrel_ht_debugfs.c
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
+ *
+ * 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 <linux/netdevice.h>
+#include <linux/types.h>
+#include <linux/skbuff.h>
+#include <linux/debugfs.h>
+#include <linux/ieee80211.h>
+#include <net/mac80211.h>
+#include "rc80211_minstrel.h"
+#include "rc80211_minstrel_ht.h"
+
+extern const struct mcs_group minstrel_mcs_groups[];
+
+static int
+minstrel_ht_stats_open(struct inode *inode, struct file *file)
+{
+ struct minstrel_ht_sta_priv *msp = inode->i_private;
+ struct minstrel_ht_sta *mi = &msp->ht;
+ struct minstrel_debugfs_info *ms;
+ unsigned int i, j, tp, prob, eprob;
+ char *p;
+ int ret;
+
+ if (!msp->is_ht) {
+ inode->i_private = &msp->legacy;
+ ret = minstrel_stats_open(inode, file);
+ inode->i_private = msp;
+ return ret;
+ }
+
+ ms = kmalloc(sizeof(*ms) + 8192, GFP_KERNEL);
+ if (!ms)
+ return -ENOMEM;
+
+ file->private_data = ms;
+ p = ms->buf;
+ p += sprintf(p, "type rate throughput ewma prob this prob "
+ "this succ/attempt success attempts\n");
+ for (i = 0; i < MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS; i++) {
+ char htmode = '2';
+ char gimode = 'L';
+
+ if (!mi->groups[i].supported)
+ continue;
+
+ if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
+ htmode = '4';
+ if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI)
+ gimode = 'S';
+
+ for (j = 0; j < MCS_GROUP_RATES; j++) {
+ struct minstrel_rate_stats *mr = &mi->groups[i].rates[j];
+ int idx = i * MCS_GROUP_RATES + j;
+
+ if (!(mi->groups[i].supported & BIT(j)))
+ continue;
+
+ p += sprintf(p, "HT%c0/%cGI ", htmode, gimode);
+
+ *(p++) = (idx == mi->max_tp_rate) ? 'T' : ' ';
+ *(p++) = (idx == mi->max_tp_rate2) ? 't' : ' ';
+ *(p++) = (idx == mi->max_prob_rate) ? 'P' : ' ';
+ p += sprintf(p, "MCS%-2u", (minstrel_mcs_groups[i].streams - 1) *
+ MCS_GROUP_RATES + j);
+
+ tp = mr->cur_tp / 10;
+ prob = MINSTREL_TRUNC(mr->cur_prob * 1000);
+ eprob = MINSTREL_TRUNC(mr->probability * 1000);
+
+ p += sprintf(p, " %6u.%1u %6u.%1u %6u.%1u "
+ "%3u(%3u) %8llu %8llu\n",
+ tp / 10, tp % 10,
+ eprob / 10, eprob % 10,
+ prob / 10, prob % 10,
+ mr->last_success,
+ mr->last_attempts,
+ (unsigned long long)mr->succ_hist,
+ (unsigned long long)mr->att_hist);
+ }
+ }
+ p += sprintf(p, "\nTotal packet count:: ideal %d "
+ "lookaround %d\n",
+ max(0, (int) mi->total_packets - (int) mi->sample_packets),
+ mi->sample_packets);
+ p += sprintf(p, "Average A-MPDU length: %d.%d\n",
+ MINSTREL_TRUNC(mi->avg_ampdu_len),
+ MINSTREL_TRUNC(mi->avg_ampdu_len * 10) % 10);
+ ms->len = p - ms->buf;
+
+ return 0;
+}
+
+static const struct file_operations minstrel_ht_stat_fops = {
+ .owner = THIS_MODULE,
+ .open = minstrel_ht_stats_open,
+ .read = minstrel_stats_read,
+ .release = minstrel_stats_release,
+};
+
+void
+minstrel_ht_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir)
+{
+ struct minstrel_ht_sta_priv *msp = priv_sta;
+
+ msp->dbg_stats = debugfs_create_file("rc_stats", S_IRUGO, dir, msp,
+ &minstrel_ht_stat_fops);
+}
+
+void
+minstrel_ht_remove_sta_debugfs(void *priv, void *priv_sta)
+{
+ struct minstrel_ht_sta_priv *msp = priv_sta;
+
+ debugfs_remove(msp->dbg_stats);
+}
--- a/net/mac80211/Kconfig
+++ b/net/mac80211/Kconfig
@@ -33,6 +33,13 @@ config MAC80211_RC_MINSTREL
---help---
This option enables the 'minstrel' TX rate control algorithm
+config MAC80211_RC_MINSTREL_HT
+ bool "Minstrel 802.11n support" if EMBEDDED
+ depends on MAC80211_RC_MINSTREL
+ default y
+ ---help---
+ This option enables the 'minstrel_ht' TX rate control algorithm
+
choice
prompt "Default rate control algorithm"
depends on MAC80211_HAS_RC
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2010-05-13 14:48 UTC | newest]
Thread overview: (only message) (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2010-05-13 14:48 [PATCH] mac80211: add the minstrel_ht rate control algorithm Felix Fietkau
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.