/*
* For the throughput calculation, limit the probability value to 90% to
-@@ -780,7 +784,7 @@ minstrel_calc_retransmit(struct minstrel
+@@ -755,12 +759,19 @@ minstrel_ht_tx_status(void *priv, struct
+ 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)
+ {
+ 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;
+@@ -779,8 +790,7 @@ minstrel_calc_retransmit(struct minstrel
+ mrs->retry_count_rtscts = 2;
mrs->retry_updated = true;
- group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
+- group = &minstrel_mcs_groups[index / MCS_GROUP_RATES];
- tx_time_data = group->duration[index % MCS_GROUP_RATES] * ampdu_len / 1000;
-+ tx_time_data = (group->duration[index % MCS_GROUP_RATES] << group->shift) * ampdu_len / 1000;
++ tx_time_data = minstrel_get_duration(index) * ampdu_len / 1000;
/* Contention time for first 2 tries */
ctime = (t_slot * cw) >> 1;
-@@ -880,14 +884,14 @@ minstrel_ht_get_max_amsdu_len(struct min
+@@ -874,20 +884,24 @@ minstrel_ht_get_max_amsdu_len(struct min
+ int group = mi->max_prob_rate / MCS_GROUP_RATES;
+ const struct mcs_group *g = &minstrel_mcs_groups[group];
+ int rate = mi->max_prob_rate % MCS_GROUP_RATES;
++ unsigned int duration;
+
+ /* Disable A-MSDU if max_prob_rate is bad */
+ if (mi->groups[group].rates[rate].prob_ewma < MINSTREL_FRAC(50, 100))
return 1;
++ duration = g->duration[rate];
++ duration <<= g->shift;
++
/* If the rate is slower than single-stream MCS1, make A-MSDU limit small */
- if (g->duration[rate] > MCS_DURATION(1, 0, 52))
-+ if ((g->duration[rate] << g->shift) > MCS_DURATION(1, 0, 52))
++ if (duration > MCS_DURATION(1, 0, 52))
return 500;
/*
* data packet size
*/
- if (g->duration[rate] > MCS_DURATION(1, 0, 104))
-+ if ((g->duration[rate] << g->shift) > MCS_DURATION(1, 0, 104))
++ if (duration > MCS_DURATION(1, 0, 104))
return 1600;
/*
-@@ -895,7 +899,7 @@ minstrel_ht_get_max_amsdu_len(struct min
+@@ -895,7 +909,7 @@ minstrel_ht_get_max_amsdu_len(struct min
* rate success probability is less than 75%, limit A-MSDU to twice the usual
* data packet size
*/
- if (g->duration[rate] > MCS_DURATION(1, 0, 260) ||
-+ if ((g->duration[rate] << g->shift) > MCS_DURATION(1, 0, 260) ||
++ if (duration > MCS_DURATION(1, 0, 260) ||
(minstrel_ht_get_prob_ewma(mi, mi->max_tp_rate[0]) <
MINSTREL_FRAC(75, 100)))
return 3200;
-@@ -946,7 +950,7 @@ 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];
-+ return group->duration[index % MCS_GROUP_RATES] << group->shift;
+@@ -942,13 +956,6 @@ minstrel_ht_update_rates(struct minstrel
+ rate_control_set_rates(mp->hw, mi->sta, 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)
+ {
--- a/net/mac80211/rc80211_minstrel_ht.h
+++ b/net/mac80211/rc80211_minstrel_ht.h
@@ -33,9 +33,10 @@
extern const struct mcs_group minstrel_mcs_groups[];
--- a/net/mac80211/rc80211_minstrel_ht_debugfs.c
+++ b/net/mac80211/rc80211_minstrel_ht_debugfs.c
-@@ -95,7 +95,7 @@ minstrel_ht_stats_dump(struct minstrel_h
+@@ -58,6 +58,7 @@ minstrel_ht_stats_dump(struct minstrel_h
+ static const int bitrates[4] = { 10, 20, 55, 110 };
+ int idx = i * MCS_GROUP_RATES + j;
+ unsigned int prob_ewmsd;
++ unsigned int duration;
+
+ if (!(mi->supported[i] & BIT(j)))
+ continue;
+@@ -95,7 +96,9 @@ minstrel_ht_stats_dump(struct minstrel_h
p += sprintf(p, " %3u ", idx);
/* tx_time[rate(i)] in usec */
- tx_time = DIV_ROUND_CLOSEST(mg->duration[j], 1000);
-+ tx_time = DIV_ROUND_CLOSEST(mg->duration[j] << mg->shift, 1000);
++ duration = mg->duration[j];
++ duration <<= mg->shift;
++ tx_time = DIV_ROUND_CLOSEST(duration, 1000);
p += sprintf(p, "%6u ", tx_time);
tp_max = minstrel_ht_get_tp_avg(mi, i, j, MINSTREL_FRAC(100, 100));
-@@ -238,7 +238,7 @@ minstrel_ht_stats_csv_dump(struct minstr
+@@ -204,6 +207,7 @@ minstrel_ht_stats_csv_dump(struct minstr
+ static const int bitrates[4] = { 10, 20, 55, 110 };
+ int idx = i * MCS_GROUP_RATES + j;
+ unsigned int prob_ewmsd;
++ unsigned int duration;
+
+ if (!(mi->supported[i] & BIT(j)))
+ continue;
+@@ -238,7 +242,10 @@ minstrel_ht_stats_csv_dump(struct minstr
}
p += sprintf(p, "%u,", idx);
- tx_time = DIV_ROUND_CLOSEST(mg->duration[j], 1000);
-+ tx_time = DIV_ROUND_CLOSEST(mg->duration[j] << mg->shift, 1000);
++
++ duration = mg->duration[j];
++ duration <<= mg->shift;
++ tx_time = DIV_ROUND_CLOSEST(duration, 1000);
p += sprintf(p, "%u,", tx_time);
tp_max = minstrel_ht_get_tp_avg(mi, i, j, MINSTREL_FRAC(100, 100));
--- /dev/null
+From: Felix Fietkau <nbd@nbd.name>
+Date: Thu, 1 Mar 2018 13:28:48 +0100
+Subject: [PATCH] mac80211: minstrel: fix sampling/reporting of CCK rates
+ in HT mode
+
+Long/short preamble selection cannot be sampled separately, since it
+depends on the BSS state. Because of that, sampling attempts to
+currently not used preamble modes are not counted in the statistics,
+which leads to CCK rates being sampled too often.
+
+Fix statistics accounting for long/short preamble by increasing the
+index where necessary.
+Fix excessive CCK rate sampling by dropping unsupported sample attempts.
+
+This improves throughput on 2.4 GHz channels
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/net/mac80211/rc80211_minstrel_ht.c
++++ b/net/mac80211/rc80211_minstrel_ht.c
+@@ -281,7 +281,8 @@ minstrel_ht_get_stats(struct minstrel_pr
+ break;
+
+ /* short preamble */
+- if (!(mi->supported[group] & BIT(idx)))
++ if ((mi->supported[group] & BIT(idx + 4)) &&
++ (rate->flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE))
+ idx += 4;
+ }
+ return &mi->groups[group].rates[idx];
+@@ -1080,18 +1081,22 @@ minstrel_ht_get_rate(void *priv, struct
+ return;
+
+ sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES];
++ sample_idx %= MCS_GROUP_RATES;
++
++ if ((sample_idx >= 4) != txrc->short_preamble)
++ return;
++
+ info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
+ rate->count = 1;
+
+- if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
++ if (sample_group == &minstrel_mcs_groups[MINSTREL_CCK_GROUP]) {
+ int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
+ rate->idx = mp->cck_rates[idx];
+ } else if (sample_group->flags & IEEE80211_TX_RC_VHT_MCS) {
+ ieee80211_rate_set_vht(rate, sample_idx % MCS_GROUP_RATES,
+ sample_group->streams);
+ } else {
+- rate->idx = sample_idx % MCS_GROUP_RATES +
+- (sample_group->streams - 1) * 8;
++ rate->idx = sample_idx + (sample_group->streams - 1) * 8;
+ }
+
+ rate->flags = sample_group->flags;