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mac80211: add the minstrel_ht rate control algorithm

Browse Source 
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Felix Fietkau 2010-05-13 16:48:03 +02:00 committed by John W. Linville
parent b4df47081b
commit ec8aa669b8
7 changed files with 1103 additions and 0 deletions
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7
net/mac80211/Kconfig
View File

@ -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

4
net/mac80211/Makefile
View File

@ -51,7 +51,11 @@ rc80211_pid-$(CONFIG_MAC80211_DEBUGFS) += rc80211_pid_debugfs.o
rc80211_minstrel-y := rc80211_minstrel.o
rc80211_minstrel-$(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__

7
net/mac80211/main.c
View File

@ -704,6 +704,10 @@ 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;
@ -716,6 +720,8 @@ static int __init ieee80211_init(void)
err_netdev:
rc80211_pid_exit();
err_pid:
rc80211_minstrel_ht_exit();
err_minstrel:
rc80211_minstrel_exit();
return ret;
@ -724,6 +730,7 @@ static int __init ieee80211_init(void)
static void __exit ieee80211_exit(void)
{
rc80211_pid_exit();
rc80211_minstrel_ht_exit();
rc80211_minstrel_exit();
/*

13
net/mac80211/rate.h
View File

@ -147,5 +147,18 @@ static inline void rc80211_minstrel_exit(void)
}
#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 */

824
net/mac80211/rc80211_minstrel_ht.c Normal file
View File

@ -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);
}

128
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/*
* 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

120
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/*
* 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);
}