static void
minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
int index)
{
struct minstrel_rate_stats *mrs;
const struct mcs_group *group;
unsigned int tx_time, tx_time_rtscts, tx_time_data;
unsigned int cw = mp->cw_min;
unsigned int ctime = 0;
unsigned int t_slot = 9; /* FIXME */
unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);
unsigned int overhead = 0, overhead_rtscts = 0;
mrs = minstrel_get_ratestats(mi, index);
if (mrs->prob_ewma < MINSTREL_FRAC(1, 10)) {
mrs->retry_count = 1;
mrs->retry_count_rtscts = 1;
return;
}
mrs->retry_count = 2;
mrs->retry_count_rtscts = 2;
mrs->retry_updated = true;
group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
/* Contention time for first 2 tries */
ctime = (t_slot * cw) >> 1;
cw = min((cw << 1) | 1, mp->cw_max);
ctime += (t_slot * cw) >> 1;
cw = min((cw << 1) | 1, mp->cw_max);
if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {
overhead = mi->overhead;
overhead_rtscts = mi->overhead_rtscts;
}
/* Total TX time for data and Contention after first 2 tries */
tx_time = ctime + 2 * (overhead + tx_time_data);
tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);
/* See how many more tries we can fit inside segment size */
do {
/* Contention time for this try */
ctime = (t_slot * cw) >> 1;
cw = min((cw << 1) | 1, mp->cw_max);
/* Total TX time after this try */
tx_time += ctime + overhead + tx_time_data;
tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;
if (tx_time_rtscts < mp->segment_size)
mrs->retry_count_rtscts++;
} while ((tx_time < mp->segment_size) &&
(++mrs->retry_count < mp->max_retry));
}
static void
minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
struct ieee80211_sta_rates *ratetbl, int offset, int index)
{
const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
struct minstrel_rate_stats *mrs;
u8 idx;
u16 flags = group->flags;
mrs = minstrel_get_ratestats(mi, index);
if (!mrs->retry_updated)
minstrel_calc_retransmit(mp, mi, index);
if (mrs->prob_ewma < MINSTREL_FRAC(20, 100) || !mrs->retry_count) {
ratetbl->rate[offset].count = 2;
ratetbl->rate[offset].count_rts = 2;
ratetbl->rate[offset].count_cts = 2;
} else {
ratetbl->rate[offset].count = mrs->retry_count;
ratetbl->rate[offset].count_cts = mrs->retry_count;
ratetbl->rate[offset].count_rts = mrs->retry_count_rtscts;
}
if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP)
idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
else if (flags & IEEE80211_TX_RC_VHT_MCS)
idx = ((group->streams - 1) << 4) |
((index % MCS_GROUP_RATES) & 0xF);
else
idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8;
/* enable RTS/CTS if needed:
* - if station is in dynamic SMPS (and streams > 1)
* - for fallback rates, to increase chances of getting through
*/
if (offset > 0 ||
(mi->sta->smps_mode == IEEE80211_SMPS_DYNAMIC &&
group->streams > 1)) {
ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
flags |= IEEE80211_TX_RC_USE_RTS_CTS;
}
ratetbl->rate[offset].idx = idx;
ratetbl->rate[offset].flags = flags;
}
static void
minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
struct ieee80211_sta_rates *ratetbl, int offset, int index)
{
const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
struct minstrel_rate_stats *mr;
u8 idx;
u16 flags;
mr = minstrel_get_ratestats(mi, index);
if (!mr->retry_updated)
minstrel_calc_retransmit(mp, mi, index);
if (mr->probability < MINSTREL_FRAC(20, 100) || !mr->retry_count) {
ratetbl->rate[offset].count = 2;
ratetbl->rate[offset].count_rts = 2;
ratetbl->rate[offset].count_cts = 2;
} else {
ratetbl->rate[offset].count = mr->retry_count;
ratetbl->rate[offset].count_cts = mr->retry_count;
ratetbl->rate[offset].count_rts = mr->retry_count_rtscts;
}
if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
flags = 0;
} else {
idx = index % MCS_GROUP_RATES +
(group->streams - 1) * MCS_GROUP_RATES;
flags = IEEE80211_TX_RC_MCS | group->flags;
}
if (offset > 0) {
ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
flags |= IEEE80211_TX_RC_USE_RTS_CTS;
}
ratetbl->rate[offset].idx = idx;
ratetbl->rate[offset].flags = flags;
}
/*
* Try to increase robustness of max_prob rate by decrease number of
* streams if possible.
*/
static inline void
minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi)
{
struct minstrel_mcs_group_data *mg;
struct minstrel_rate_stats *mr;
int tmp_max_streams, group;
int tmp_tp = 0;
tmp_max_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
MCS_GROUP_RATES].streams;
for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
mg = &mi->groups[group];
if (!mg->supported || group == MINSTREL_CCK_GROUP)
continue;
mr = minstrel_get_ratestats(mi, mg->max_group_prob_rate);
if (tmp_tp < mr->cur_tp &&
(minstrel_mcs_groups[group].streams < tmp_max_streams)) {
mi->max_prob_rate = mg->max_group_prob_rate;
tmp_tp = mr->cur_tp;
}
}
}
static void
minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
struct ieee80211_sta *sta, void *priv_sta,
struct ieee80211_tx_info *info)
{
struct minstrel_ht_sta_priv *msp = priv_sta;
struct minstrel_ht_sta *mi = &msp->ht;
struct ieee80211_tx_rate *ar = info->status.rates;
struct minstrel_rate_stats *rate, *rate2;
struct minstrel_priv *mp = priv;
bool last, update = false;
int i;
if (!msp->is_ht)
return mac80211_minstrel.tx_status_noskb(priv, sband, sta,
&msp->legacy, info);
/* 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->flags & IEEE80211_TX_STAT_AMPDU)) {
info->status.ampdu_ack_len =
(info->flags & IEEE80211_TX_STAT_ACK ? 1 : 0);
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 = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
mi->sample_tries = 1;
mi->sample_count--;
}
if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
mi->sample_packets += info->status.ampdu_len;
last = !minstrel_ht_txstat_valid(mp, &ar[0]);
for (i = 0; !last; i++) {
last = (i == IEEE80211_TX_MAX_RATES - 1) ||
!minstrel_ht_txstat_valid(mp, &ar[i + 1]);
rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
if (last)
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[0]);
if (rate->attempts > 30 &&
MINSTREL_FRAC(rate->success, rate->attempts) <
MINSTREL_FRAC(20, 100)) {
minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true);
update = true;
}
rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]);
if (rate2->attempts > 30 &&
MINSTREL_FRAC(rate2->success, rate2->attempts) <
MINSTREL_FRAC(20, 100)) {
minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false);
update = true;
}
if (time_after(jiffies, mi->last_stats_update +
(mp->update_interval / 2 * HZ) / 1000)) {
update = true;
minstrel_ht_update_stats(mp, mi);
}
if (update)
minstrel_ht_update_rates(mp, mi);
}
/*
* 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;
bool mi_rates_valid = false;
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;
for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
bool mg_rates_valid = false;
cur_prob = 0;
cur_prob_tp = 0;
cur_tp = 0;
cur_tp2 = 0;
mg = &mi->groups[group];
if (!mg->supported)
continue;
mi->sample_count++;
for (i = 0; i < MCS_GROUP_RATES; i++) {
if (!(mg->supported & BIT(i)))
continue;
index = MCS_GROUP_RATES * group + i;
/* initialize rates selections starting indexes */
if (!mg_rates_valid) {
mg->max_tp_rate = mg->max_tp_rate2 =
mg->max_prob_rate = i;
if (!mi_rates_valid) {
mi->max_tp_rate = mi->max_tp_rate2 =
mi->max_prob_rate = index;
mi_rates_valid = true;
}
mg_rates_valid = true;
}
mr = &mg->rates[i];
mr->retry_updated = false;
minstrel_calc_rate_ewma(mr);
minstrel_ht_calc_tp(mi, group, i);
if (!mr->cur_tp)
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;
cur_prob_tp = mr->cur_tp;
}
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 all available rates during each interval */
mi->sample_count *= 8;
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_tp_rate);
if (cur_tp < mr->cur_tp) {
mi->max_tp_rate2 = mi->max_tp_rate;
cur_tp2 = cur_tp;
mi->max_tp_rate = mg->max_tp_rate;
cur_tp = mr->cur_tp;
mi->max_prob_streams = minstrel_mcs_groups[group].streams - 1;
}
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;
}
}
if (mi->max_prob_streams < 1)
mi->max_prob_streams = 1;
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 <= mi->max_prob_streams) {
mi->max_prob_rate = mg->max_prob_rate;
cur_prob = mr->cur_prob;
cur_prob_tp = mr->cur_tp;
}
}
#ifdef CPTCFG_MAC80211_DEBUGFS
/* use fixed index if set */
if (mp->fixed_rate_idx != -1) {
mi->max_tp_rate = mp->fixed_rate_idx;
mi->max_tp_rate2 = mp->fixed_rate_idx;
mi->max_prob_rate = mp->fixed_rate_idx;
}
#endif
mi->stats_update = jiffies;
}
