#define AVG_AMPDU_SIZE 16
#define AVG_PKT_SIZE 1200
+#define SAMPLE_SWITCH_THR 100
+
/* Number of bits for an average sized packet */
#define MCS_NBITS ((AVG_PKT_SIZE * AVG_AMPDU_SIZE) << 3)
[GROUP_IDX(_streams, _sgi, _ht40)] = { \
.streams = _streams, \
.shift = _s, \
+ .bw = _ht40, \
.flags = \
IEEE80211_TX_RC_MCS | \
(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
[VHT_GROUP_IDX(_streams, _sgi, _bw)] = { \
.streams = _streams, \
.shift = _s, \
+ .bw = _bw, \
.flags = \
IEEE80211_TX_RC_VHT_MCS | \
(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
tmp_mcs_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
- if (tmp_cck_tp > tmp_mcs_tp) {
+ if (tmp_cck_tp_rate && tmp_cck_tp > tmp_mcs_tp) {
for(i = 0; i < MAX_THR_RATES; i++) {
minstrel_ht_sort_best_tp_rates(mi, tmp_cck_tp_rate[i],
tmp_mcs_tp_rate);
}
}
+static inline int
+minstrel_get_duration(int index)
+{
+ const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
+ unsigned int duration = group->duration[index % MCS_GROUP_RATES];
+ return duration << group->shift;
+}
+
+static bool
+minstrel_ht_probe_group(struct minstrel_ht_sta *mi, const struct mcs_group *tp_group,
+ int tp_idx, const struct mcs_group *group)
+{
+ if (group->bw < tp_group->bw)
+ return false;
+
+ if (group->streams == tp_group->streams)
+ return true;
+
+ if (tp_idx < 4 && group->streams == tp_group->streams - 1)
+ return true;
+
+ return group->streams == tp_group->streams + 1;
+}
+
+static void
+minstrel_ht_find_probe_rates(struct minstrel_ht_sta *mi, u16 *rates, int *n_rates,
+ bool faster_rate)
+{
+ const struct mcs_group *group, *tp_group;
+ int i, g, max_dur;
+ int tp_idx;
+
+ tp_group = &minstrel_mcs_groups[mi->max_tp_rate[0] / MCS_GROUP_RATES];
+ tp_idx = mi->max_tp_rate[0] % MCS_GROUP_RATES;
+
+ max_dur = minstrel_get_duration(mi->max_tp_rate[0]);
+ if (faster_rate)
+ max_dur -= max_dur / 16;
+
+ for (g = 0; g < MINSTREL_GROUPS_NB; g++) {
+ u16 supported = mi->supported[g];
+
+ if (!supported)
+ continue;
+
+ group = &minstrel_mcs_groups[g];
+ if (!minstrel_ht_probe_group(mi, tp_group, tp_idx, group))
+ continue;
+
+ for (i = 0; supported; supported >>= 1, i++) {
+ int idx;
+
+ if (!(supported & 1))
+ continue;
+
+ if ((group->duration[i] << group->shift) > max_dur)
+ continue;
+
+ idx = g * MCS_GROUP_RATES + i;
+ if (idx == mi->max_tp_rate[0])
+ continue;
+
+ rates[(*n_rates)++] = idx;
+ break;
+ }
+ }
+}
+
+static void
+minstrel_ht_rate_sample_switch(struct minstrel_priv *mp,
+ struct minstrel_ht_sta *mi)
+{
+ struct minstrel_rate_stats *mrs;
+ u16 rates[MINSTREL_GROUPS_NB];
+ int n_rates = 0;
+ int probe_rate = 0;
+ bool faster_rate;
+ int i;
+ u8 random;
+
+ /*
+ * Use rate switching instead of probing packets for devices with
+ * little control over retry fallback behavior
+ */
+ if (mp->hw->max_rates > 1)
+ return;
+
+ /*
+ * If the current EWMA prob is >75%, look for a rate that's 6.25%
+ * faster than the max tp rate.
+ * If that fails, look again for a rate that is at least as fast
+ */
+ mrs = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
+ faster_rate = mrs->prob_ewma > MINSTREL_FRAC(75, 100);
+ minstrel_ht_find_probe_rates(mi, rates, &n_rates, faster_rate);
+ if (!n_rates && faster_rate)
+ minstrel_ht_find_probe_rates(mi, rates, &n_rates, false);
+
+ /* If no suitable rate was found, try to pick the next one in the group */
+ if (!n_rates) {
+ int g_idx = mi->max_tp_rate[0] / MCS_GROUP_RATES;
+ u16 supported = mi->supported[g_idx];
+
+ supported >>= mi->max_tp_rate[0] % MCS_GROUP_RATES;
+ for (i = 0; supported; i++) {
+ if (!(supported & 1))
+ continue;
+
+ probe_rate = mi->max_tp_rate[0] + i;
+ goto out;
+ }
+
+ return;
+ }
+
+ i = 0;
+ if (n_rates > 1) {
+ random = prandom_u32();
+ i = random % n_rates;
+ }
+ probe_rate = rates[i];
+
+out:
+ mi->sample_rate = probe_rate;
+ mi->sample_mode = MINSTREL_SAMPLE_ACTIVE;
+}
+
/*
* Update rate statistics and select new primary rates
*
* 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)
+minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
+ bool sample)
{
struct minstrel_mcs_group_data *mg;
struct minstrel_rate_stats *mrs;
u16 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
u16 tmp_cck_tp_rate[MAX_THR_RATES], index;
+ mi->sample_mode = MINSTREL_SAMPLE_IDLE;
+
+ if (sample) {
+ mi->total_packets_cur = mi->total_packets -
+ mi->total_packets_last;
+ mi->total_packets_last = mi->total_packets;
+ }
+ if (!mp->sample_switch)
+ sample = false;
+ if (mi->total_packets_cur < SAMPLE_SWITCH_THR && mp->sample_switch != 1)
+ sample = false;
+
if (mi->ampdu_packets > 0) {
if (!ieee80211_hw_check(mp->hw, TX_STATUS_NO_AMPDU_LEN))
mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
mi->sample_slow = 0;
mi->sample_count = 0;
- /* Initialize global rate indexes */
- for(j = 0; j < MAX_THR_RATES; j++){
- tmp_mcs_tp_rate[j] = 0;
- tmp_cck_tp_rate[j] = 0;
- }
+ memset(tmp_mcs_tp_rate, 0, sizeof(tmp_mcs_tp_rate));
+ memset(tmp_cck_tp_rate, 0, sizeof(tmp_cck_tp_rate));
+ if (mi->supported[MINSTREL_CCK_GROUP])
+ for (j = 0; j < ARRAY_SIZE(tmp_cck_tp_rate); j++)
+ tmp_cck_tp_rate[j] = MINSTREL_CCK_GROUP * MCS_GROUP_RATES;
+
+ if (mi->supported[MINSTREL_VHT_GROUP_0])
+ index = MINSTREL_VHT_GROUP_0 * MCS_GROUP_RATES;
+ else
+ index = MINSTREL_HT_GROUP_0 * MCS_GROUP_RATES;
+
+ for (j = 0; j < ARRAY_SIZE(tmp_mcs_tp_rate); j++)
+ tmp_mcs_tp_rate[j] = index;
/* Find best rate sets within all MCS groups*/
for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
/* (re)Initialize group rate indexes */
for(j = 0; j < MAX_THR_RATES; j++)
- tmp_group_tp_rate[j] = group;
+ tmp_group_tp_rate[j] = MCS_GROUP_RATES * group;
for (i = 0; i < MCS_GROUP_RATES; i++) {
if (!(mi->supported[group] & BIT(i)))
/* try to sample all available rates during each interval */
mi->sample_count *= 8;
+ if (sample)
+ minstrel_ht_rate_sample_switch(mp, mi);
+
#ifdef CONFIG_MAC80211_DEBUGFS
/* use fixed index if set */
if (mp->fixed_rate_idx != -1) {
for (i = 0; i < 4; i++)
mi->max_tp_rate[i] = mp->fixed_rate_idx;
mi->max_prob_rate = mp->fixed_rate_idx;
+ mi->sample_mode = MINSTREL_SAMPLE_IDLE;
}
#endif
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_rate_stats *rate, *rate2, *rate_sample = NULL;
struct minstrel_priv *mp = priv;
bool last, update = false;
+ bool sample_status = false;
int i;
if (!msp->is_ht)
return mac80211_minstrel.tx_status_ext(priv, sband,
&msp->legacy, st);
+
/* This packet was aggregated but doesn't carry status info */
if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
!(info->flags & IEEE80211_TX_STAT_AMPDU))
if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
mi->sample_packets += info->status.ampdu_len;
+ if (mi->sample_mode != MINSTREL_SAMPLE_IDLE)
+ rate_sample = minstrel_get_ratestats(mi, mi->sample_rate);
+
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 (rate == rate_sample)
+ sample_status = true;
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);
+ switch (mi->sample_mode) {
+ case MINSTREL_SAMPLE_IDLE:
+ break;
+
+ case MINSTREL_SAMPLE_ACTIVE:
+ if (!sample_status)
+ break;
+
+ mi->sample_mode = MINSTREL_SAMPLE_PENDING;
update = true;
- }
+ break;
+
+ case MINSTREL_SAMPLE_PENDING:
+ if (sample_status)
+ break;
- 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;
+ minstrel_ht_update_stats(mp, mi, false);
+ break;
+ }
+
+
+ if (mp->hw->max_rates > 1) {
+ /*
+ * 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);
+ minstrel_ht_update_stats(mp, mi, true);
}
if (update)
minstrel_ht_update_rates(mp, mi);
}
-static inline int
-minstrel_get_duration(int index)
-{
- const struct mcs_group *group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
- unsigned int duration = group->duration[index % MCS_GROUP_RATES];
- return duration << group->shift;
-}
-
static void
minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
int index)
minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
{
struct ieee80211_sta_rates *rates;
+ u16 first_rate = mi->max_tp_rate[0];
int i = 0;
+ if (mi->sample_mode == MINSTREL_SAMPLE_ACTIVE)
+ first_rate = mi->sample_rate;
+
rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
if (!rates)
return;
/* Start with max_tp_rate[0] */
- minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]);
+ minstrel_ht_set_rate(mp, mi, rates, i++, first_rate);
if (mp->hw->max_rates >= 3) {
/* At least 3 tx rates supported, use max_tp_rate[1] next */
int tp_rate1, tp_rate2;
int sample_idx = 0;
+ if (mp->hw->max_rates == 1 && mp->sample_switch &&
+ (mi->total_packets_cur >= SAMPLE_SWITCH_THR ||
+ mp->sample_switch == 1))
+ return -1;
+
if (mi->sample_wait > 0) {
mi->sample_wait--;
return -1;
minstrel_get_duration(mi->max_prob_rate) * 3 < sample_dur)
return -1;
+
+ /*
+ * For devices with no configurable multi-rate retry, skip sampling
+ * below the per-group max throughput rate, and only use one sampling
+ * attempt per rate
+ */
+ if (mp->hw->max_rates == 1 &&
+ (minstrel_get_duration(mg->max_group_tp_rate[0]) < sample_dur ||
+ mrs->attempts))
+ return -1;
+
+ /* Skip already sampled slow rates */
+ if (sample_dur >= minstrel_get_duration(tp_rate1) && mrs->attempts)
+ return -1;
+
/*
* Make sure that lower rates get sampled only occasionally,
* if the link is working perfectly.
mi->supported[MINSTREL_CCK_GROUP] |= mi->cck_supported_short << 4;
/* create an initial rate table with the lowest supported rates */
- minstrel_ht_update_stats(mp, mi);
+ minstrel_ht_update_stats(mp, mi, true);
minstrel_ht_update_rates(mp, mi);
return;
if (!mp)
return NULL;
+ mp->sample_switch = -1;
+
/* contention window settings
* Just an approximation. Using the per-queue values would complicate
* the calculations and is probably unnecessary */
mp->fixed_rate_idx = (u32) -1;
debugfs_create_u32("fixed_rate_idx", S_IRUGO | S_IWUGO, debugfsdir,
&mp->fixed_rate_idx);
+ debugfs_create_u32("sample_switch", S_IRUGO | S_IWUSR, debugfsdir,
+ &mp->sample_switch);
#endif
minstrel_ht_init_cck_rates(mp);
projects / linux.git / blobdiff