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mac80211: add significant minstrel_ht performance improvements 

Completely redesign the rate sampling approach

Signed-off-by: Felix Fietkau <nbd@nbd.name>
This commit is contained in:
Felix Fietkau 2021-01-23 00:17:31 +01:00
parent 1fb413e657
commit 37752336bd
6 changed files with 1670 additions and 0 deletions
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409
package/kernel/mac80211/patches/subsys/346-mac80211-minstrel_ht-use-bitfields-to-encode-rate-in.patch Normal file
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@ -0,0 +1,409 @@
From: Felix Fietkau <nbd@nbd.name>
Date: Thu, 21 Jan 2021 18:29:30 +0100
Subject: [PATCH] mac80211: minstrel_ht: use bitfields to encode rate
indexes
Get rid of a lot of divisions and modulo operations
Reduces code size and improves performance
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -379,14 +379,14 @@ out:
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];
+ return &mi->groups[MI_RATE_GROUP(index)].rates[MI_RATE_IDX(index)];
}
-static inline int
-minstrel_get_duration(int index)
+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];
+ const struct mcs_group *group = &minstrel_mcs_groups[MI_RATE_GROUP(index)];
+ unsigned int duration = group->duration[MI_RATE_IDX(index)];
+
return duration << group->shift;
}
@@ -398,7 +398,7 @@ minstrel_ht_avg_ampdu_len(struct minstre
if (mi->avg_ampdu_len)
return MINSTREL_TRUNC(mi->avg_ampdu_len);
- if (minstrel_ht_is_legacy_group(mi->max_tp_rate[0] / MCS_GROUP_RATES))
+ if (minstrel_ht_is_legacy_group(MI_RATE_GROUP(mi->max_tp_rate[0])))
return 1;
duration = minstrel_get_duration(mi->max_tp_rate[0]);
@@ -465,14 +465,14 @@ minstrel_ht_sort_best_tp_rates(struct mi
int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
int j = MAX_THR_RATES;
- cur_group = index / MCS_GROUP_RATES;
- cur_idx = index % MCS_GROUP_RATES;
+ cur_group = MI_RATE_GROUP(index);
+ cur_idx = MI_RATE_IDX(index);
cur_prob = mi->groups[cur_group].rates[cur_idx].prob_avg;
cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx, cur_prob);
do {
- tmp_group = tp_list[j - 1] / MCS_GROUP_RATES;
- tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES;
+ tmp_group = MI_RATE_GROUP(tp_list[j - 1]);
+ tmp_idx = MI_RATE_IDX(tp_list[j - 1]);
tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx,
tmp_prob);
@@ -504,23 +504,23 @@ minstrel_ht_set_best_prob_rate(struct mi
int max_gpr_group, max_gpr_idx;
int max_gpr_tp_avg, max_gpr_prob;
- cur_group = index / MCS_GROUP_RATES;
- cur_idx = index % MCS_GROUP_RATES;
- mg = &mi->groups[index / MCS_GROUP_RATES];
- mrs = &mg->rates[index % MCS_GROUP_RATES];
+ cur_group = MI_RATE_GROUP(index);
+ cur_idx = MI_RATE_IDX(index);
+ mg = &mi->groups[cur_group];
+ mrs = &mg->rates[cur_idx];
- tmp_group = *dest / MCS_GROUP_RATES;
- tmp_idx = *dest % MCS_GROUP_RATES;
+ tmp_group = MI_RATE_GROUP(*dest);
+ tmp_idx = MI_RATE_IDX(*dest);
tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
/* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
* MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
- max_tp_group = mi->max_tp_rate[0] / MCS_GROUP_RATES;
- max_tp_idx = mi->max_tp_rate[0] % MCS_GROUP_RATES;
+ max_tp_group = MI_RATE_GROUP(mi->max_tp_rate[0]);
+ max_tp_idx = MI_RATE_IDX(mi->max_tp_rate[0]);
max_tp_prob = mi->groups[max_tp_group].rates[max_tp_idx].prob_avg;
- if (minstrel_ht_is_legacy_group(index / MCS_GROUP_RATES) &&
+ if (minstrel_ht_is_legacy_group(MI_RATE_GROUP(index)) &&
!minstrel_ht_is_legacy_group(max_tp_group))
return;
@@ -529,8 +529,8 @@ minstrel_ht_set_best_prob_rate(struct mi
mrs->prob_avg < max_tp_prob)
return;
- max_gpr_group = mg->max_group_prob_rate / MCS_GROUP_RATES;
- max_gpr_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;
+ max_gpr_group = MI_RATE_GROUP(mg->max_group_prob_rate);
+ max_gpr_idx = MI_RATE_IDX(mg->max_group_prob_rate);
max_gpr_prob = mi->groups[max_gpr_group].rates[max_gpr_idx].prob_avg;
if (mrs->prob_avg > MINSTREL_FRAC(75, 100)) {
@@ -567,13 +567,13 @@ minstrel_ht_assign_best_tp_rates(struct
unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp, tmp_prob;
int i;
- tmp_group = tmp_legacy_tp_rate[0] / MCS_GROUP_RATES;
- tmp_idx = tmp_legacy_tp_rate[0] % MCS_GROUP_RATES;
+ tmp_group = MI_RATE_GROUP(tmp_legacy_tp_rate[0]);
+ tmp_idx = MI_RATE_IDX(tmp_legacy_tp_rate[0]);
tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
tmp_cck_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
- tmp_group = tmp_mcs_tp_rate[0] / MCS_GROUP_RATES;
- tmp_idx = tmp_mcs_tp_rate[0] % MCS_GROUP_RATES;
+ tmp_group = MI_RATE_GROUP(tmp_mcs_tp_rate[0]);
+ tmp_idx = MI_RATE_IDX(tmp_mcs_tp_rate[0]);
tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
tmp_mcs_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
@@ -600,14 +600,14 @@ minstrel_ht_prob_rate_reduce_streams(str
if (!mi->sta->ht_cap.ht_supported)
return;
- tmp_max_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
- MCS_GROUP_RATES].streams;
+ group = MI_RATE_GROUP(mi->max_tp_rate[0]);
+ tmp_max_streams = minstrel_mcs_groups[group].streams;
for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
mg = &mi->groups[group];
if (!mi->supported[group] || group == MINSTREL_CCK_GROUP)
continue;
- tmp_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;
+ tmp_idx = MI_RATE_IDX(mg->max_group_prob_rate);
tmp_prob = mi->groups[group].rates[tmp_idx].prob_avg;
if (tmp_tp < minstrel_ht_get_tp_avg(mi, group, tmp_idx, tmp_prob) &&
@@ -644,8 +644,8 @@ minstrel_ht_find_probe_rates(struct mins
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;
+ tp_group = &minstrel_mcs_groups[MI_RATE_GROUP(mi->max_tp_rate[0])];
+ tp_idx = MI_RATE_IDX(mi->max_tp_rate[0]);
max_dur = minstrel_get_duration(mi->max_tp_rate[0]);
if (faster_rate)
@@ -670,7 +670,7 @@ minstrel_ht_find_probe_rates(struct mins
if ((group->duration[i] << group->shift) > max_dur)
continue;
- idx = g * MCS_GROUP_RATES + i;
+ idx = MI_RATE(g, i);
if (idx == mi->max_tp_rate[0])
continue;
@@ -712,10 +712,10 @@ minstrel_ht_rate_sample_switch(struct mi
/* 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;
+ int g_idx = MI_RATE_GROUP(mi->max_tp_rate[0]);
u16 supported = mi->supported[g_idx];
- supported >>= mi->max_tp_rate[0] % MCS_GROUP_RATES;
+ supported >>= MI_RATE_IDX(mi->max_tp_rate[0]);
for (i = 0; supported; supported >>= 1, i++) {
if (!(supported & 1))
continue;
@@ -856,22 +856,26 @@ minstrel_ht_update_stats(struct minstrel
memset(tmp_mcs_tp_rate, 0, sizeof(tmp_mcs_tp_rate));
memset(tmp_legacy_tp_rate, 0, sizeof(tmp_legacy_tp_rate));
+
if (mi->supported[MINSTREL_CCK_GROUP])
- for (j = 0; j < ARRAY_SIZE(tmp_legacy_tp_rate); j++)
- tmp_legacy_tp_rate[j] = MINSTREL_CCK_GROUP * MCS_GROUP_RATES;
+ group = MINSTREL_CCK_GROUP;
else if (mi->supported[MINSTREL_OFDM_GROUP])
- for (j = 0; j < ARRAY_SIZE(tmp_legacy_tp_rate); j++)
- tmp_legacy_tp_rate[j] = MINSTREL_OFDM_GROUP * MCS_GROUP_RATES;
+ group = MINSTREL_OFDM_GROUP;
+
+ index = MI_RATE(group, 0);
+ for (j = 0; j < ARRAY_SIZE(tmp_legacy_tp_rate); j++)
+ tmp_legacy_tp_rate[j] = index;
if (mi->supported[MINSTREL_VHT_GROUP_0])
- index = MINSTREL_VHT_GROUP_0 * MCS_GROUP_RATES;
+ group = MINSTREL_VHT_GROUP_0;
else if (ht_supported)
- index = MINSTREL_HT_GROUP_0 * MCS_GROUP_RATES;
+ group = MINSTREL_HT_GROUP_0;
else if (mi->supported[MINSTREL_CCK_GROUP])
- index = MINSTREL_CCK_GROUP * MCS_GROUP_RATES;
+ group = MINSTREL_CCK_GROUP;
else
- index = MINSTREL_OFDM_GROUP * MCS_GROUP_RATES;
+ group = MINSTREL_OFDM_GROUP;
+ index = MI_RATE(group, 0);
tmp_max_prob_rate = index;
for (j = 0; j < ARRAY_SIZE(tmp_mcs_tp_rate); j++)
tmp_mcs_tp_rate[j] = index;
@@ -888,7 +892,7 @@ minstrel_ht_update_stats(struct minstrel
/* (re)Initialize group rate indexes */
for(j = 0; j < MAX_THR_RATES; j++)
- tmp_group_tp_rate[j] = MCS_GROUP_RATES * group;
+ tmp_group_tp_rate[j] = MI_RATE(group, 0);
if (group == MINSTREL_CCK_GROUP && ht_supported)
tp_rate = tmp_legacy_tp_rate;
@@ -897,7 +901,7 @@ minstrel_ht_update_stats(struct minstrel
if (!(mi->supported[group] & BIT(i)))
continue;
- index = MCS_GROUP_RATES * group + i;
+ index = MI_RATE(group, i);
mrs = &mg->rates[i];
mrs->retry_updated = false;
@@ -929,13 +933,13 @@ minstrel_ht_update_stats(struct minstrel
continue;
mg = &mi->groups[group];
- mg->max_group_prob_rate = MCS_GROUP_RATES * group;
+ mg->max_group_prob_rate = MI_RATE(group, 0);
for (i = 0; i < MCS_GROUP_RATES; i++) {
if (!(mi->supported[group] & BIT(i)))
continue;
- index = MCS_GROUP_RATES * group + i;
+ index = MI_RATE(group, i);
/* Find max probability rate per group and global */
minstrel_ht_set_best_prob_rate(mi, &tmp_max_prob_rate,
@@ -1022,7 +1026,7 @@ minstrel_downgrade_rate(struct minstrel_
{
int group, orig_group;
- orig_group = group = *idx / MCS_GROUP_RATES;
+ orig_group = group = MI_RATE_GROUP(*idx);
while (group > 0) {
group--;
@@ -1206,7 +1210,7 @@ minstrel_calc_retransmit(struct minstrel
ctime += (t_slot * cw) >> 1;
cw = min((cw << 1) | 1, mp->cw_max);
- if (minstrel_ht_is_legacy_group(index / MCS_GROUP_RATES)) {
+ if (minstrel_ht_is_legacy_group(MI_RATE_GROUP(index))) {
overhead = mi->overhead_legacy;
overhead_rtscts = mi->overhead_legacy_rtscts;
} else {
@@ -1239,7 +1243,7 @@ static void
minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
struct ieee80211_sta_rates *ratetbl, int offset, int index)
{
- int group_idx = index / MCS_GROUP_RATES;
+ int group_idx = MI_RATE_GROUP(index);
const struct mcs_group *group = &minstrel_mcs_groups[group_idx];
struct minstrel_rate_stats *mrs;
u8 idx;
@@ -1259,7 +1263,7 @@ minstrel_ht_set_rate(struct minstrel_pri
ratetbl->rate[offset].count_rts = mrs->retry_count_rtscts;
}
- index %= MCS_GROUP_RATES;
+ index = MI_RATE_IDX(index);
if (group_idx == MINSTREL_CCK_GROUP)
idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
else if (group_idx == MINSTREL_OFDM_GROUP)
@@ -1289,17 +1293,17 @@ minstrel_ht_set_rate(struct minstrel_pri
static inline int
minstrel_ht_get_prob_avg(struct minstrel_ht_sta *mi, int rate)
{
- int group = rate / MCS_GROUP_RATES;
- rate %= MCS_GROUP_RATES;
+ int group = MI_RATE_GROUP(rate);
+ rate = MI_RATE_IDX(rate);
return mi->groups[group].rates[rate].prob_avg;
}
static int
minstrel_ht_get_max_amsdu_len(struct minstrel_ht_sta *mi)
{
- int group = mi->max_prob_rate / MCS_GROUP_RATES;
+ int group = MI_RATE_GROUP(mi->max_prob_rate);
const struct mcs_group *g = &minstrel_mcs_groups[group];
- int rate = mi->max_prob_rate % MCS_GROUP_RATES;
+ int rate = MI_RATE_IDX(mi->max_prob_rate);
unsigned int duration;
/* Disable A-MSDU if max_prob_rate is bad */
@@ -1405,7 +1409,7 @@ minstrel_get_sample_rate(struct minstrel
return -1;
mrs = &mg->rates[sample_idx];
- sample_idx += sample_group * MCS_GROUP_RATES;
+ sample_idx += MI_RATE(sample_group, 0);
tp_rate1 = mi->max_tp_rate[0];
@@ -1455,8 +1459,7 @@ minstrel_get_sample_rate(struct minstrel
* if the link is working perfectly.
*/
- cur_max_tp_streams = minstrel_mcs_groups[tp_rate1 /
- MCS_GROUP_RATES].streams;
+ cur_max_tp_streams = minstrel_mcs_groups[MI_RATE_GROUP(tp_rate1)].streams;
if (sample_dur >= minstrel_get_duration(tp_rate2) &&
(cur_max_tp_streams - 1 <
minstrel_mcs_groups[sample_group].streams ||
@@ -1484,7 +1487,7 @@ minstrel_ht_get_rate(void *priv, struct
int sample_idx;
if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
- !minstrel_ht_is_legacy_group(mi->max_prob_rate / MCS_GROUP_RATES))
+ !minstrel_ht_is_legacy_group(MI_RATE_GROUP(mi->max_prob_rate)))
minstrel_aggr_check(sta, txrc->skb);
info->flags |= mi->tx_flags;
@@ -1512,8 +1515,8 @@ minstrel_ht_get_rate(void *priv, struct
if (sample_idx < 0)
return;
- sample_group = &minstrel_mcs_groups[sample_idx / MCS_GROUP_RATES];
- sample_idx %= MCS_GROUP_RATES;
+ sample_group = &minstrel_mcs_groups[MI_RATE_GROUP(sample_idx)];
+ sample_idx = MI_RATE_IDX(sample_idx);
if (sample_group == &minstrel_mcs_groups[MINSTREL_CCK_GROUP] &&
(sample_idx >= 4) != txrc->short_preamble)
@@ -1529,7 +1532,7 @@ minstrel_ht_get_rate(void *priv, struct
int idx = sample_idx % ARRAY_SIZE(mp->ofdm_rates[0]);
rate->idx = mp->ofdm_rates[mi->band][idx];
} else if (sample_group->flags & IEEE80211_TX_RC_VHT_MCS) {
- ieee80211_rate_set_vht(rate, sample_idx % MCS_GROUP_RATES,
+ ieee80211_rate_set_vht(rate, MI_RATE_IDX(sample_idx),
sample_group->streams);
} else {
rate->idx = sample_idx + (sample_group->streams - 1) * 8;
@@ -1898,8 +1901,8 @@ static u32 minstrel_ht_get_expected_thro
struct minstrel_ht_sta *mi = priv_sta;
int i, j, prob, tp_avg;
- i = mi->max_tp_rate[0] / MCS_GROUP_RATES;
- j = mi->max_tp_rate[0] % MCS_GROUP_RATES;
+ i = MI_RATE_GROUP(mi->max_tp_rate[0]);
+ j = MI_RATE_IDX(mi->max_tp_rate[0]);
prob = mi->groups[i].rates[j].prob_avg;
/* convert tp_avg from pkt per second in kbps */
--- a/net/mac80211/rc80211_minstrel_ht.h
+++ b/net/mac80211/rc80211_minstrel_ht.h
@@ -6,6 +6,8 @@
#ifndef __RC_MINSTREL_HT_H
#define __RC_MINSTREL_HT_H
+#include <linux/bitfield.h>
+
/* number of highest throughput rates to consider*/
#define MAX_THR_RATES 4
#define SAMPLE_COLUMNS 10 /* number of columns in sample table */
@@ -57,6 +59,17 @@
#define MCS_GROUP_RATES 10
+#define MI_RATE_IDX_MASK GENMASK(3, 0)
+#define MI_RATE_GROUP_MASK GENMASK(15, 4)
+
+#define MI_RATE(_group, _idx) \
+ (FIELD_PREP(MI_RATE_GROUP_MASK, _group) | \
+ FIELD_PREP(MI_RATE_IDX_MASK, _idx))
+
+#define MI_RATE_IDX(_rate) FIELD_GET(MI_RATE_IDX_MASK, _rate)
+#define MI_RATE_GROUP(_rate) FIELD_GET(MI_RATE_GROUP_MASK, _rate)
+
+
struct minstrel_priv {
struct ieee80211_hw *hw;
bool has_mrr;
--- a/net/mac80211/rc80211_minstrel_ht_debugfs.c
+++ b/net/mac80211/rc80211_minstrel_ht_debugfs.c
@@ -56,7 +56,7 @@ minstrel_ht_stats_dump(struct minstrel_h
for (j = 0; j < MCS_GROUP_RATES; j++) {
struct minstrel_rate_stats *mrs = &mi->groups[i].rates[j];
- int idx = i * MCS_GROUP_RATES + j;
+ int idx = MI_RATE(i, j);
unsigned int duration;
if (!(mi->supported[i] & BIT(j)))
@@ -201,7 +201,7 @@ minstrel_ht_stats_csv_dump(struct minstr
for (j = 0; j < MCS_GROUP_RATES; j++) {
struct minstrel_rate_stats *mrs = &mi->groups[i].rates[j];
- int idx = i * MCS_GROUP_RATES + j;
+ int idx = MI_RATE(i, j);
unsigned int duration;
if (!(mi->supported[i] & BIT(j)))

54
package/kernel/mac80211/patches/subsys/347-mac80211-minstrel_ht-update-total-packets-counter-in.patch Normal file
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@ -0,0 +1,54 @@
From: Felix Fietkau <nbd@nbd.name>
Date: Fri, 22 Jan 2021 18:21:13 +0100
Subject: [PATCH] mac80211: minstrel_ht: update total packets counter in tx
status path
Keep the update in one place and prepare for further rework
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -1093,6 +1093,16 @@ minstrel_ht_tx_status(void *priv, struct
info->status.ampdu_len = 1;
}
+ /* wraparound */
+ if (mi->total_packets >= ~0 - info->status.ampdu_len) {
+ mi->total_packets = 0;
+ mi->sample_packets = 0;
+ }
+
+ mi->total_packets += info->status.ampdu_len;
+ if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
+ mi->sample_packets += info->status.ampdu_len;
+
mi->ampdu_packets++;
mi->ampdu_len += info->status.ampdu_len;
@@ -1104,9 +1114,6 @@ minstrel_ht_tx_status(void *priv, struct
mi->sample_count--;
}
- 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);
@@ -1504,14 +1511,6 @@ minstrel_ht_get_rate(void *priv, struct
else
sample_idx = minstrel_get_sample_rate(mp, mi);
- mi->total_packets++;
-
- /* wraparound */
- if (mi->total_packets == ~0) {
- mi->total_packets = 0;
- mi->sample_packets = 0;
- }
-
if (sample_idx < 0)
return;

102
package/kernel/mac80211/patches/subsys/348-mac80211-minstrel_ht-reduce-the-need-to-sample-slowe.patch Normal file
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@ -0,0 +1,102 @@
From: Felix Fietkau <nbd@nbd.name>
Date: Fri, 22 Jan 2021 19:24:59 +0100
Subject: [PATCH] mac80211: minstrel_ht: reduce the need to sample slower
rates
In order to more gracefully be able to fall back to lower rates without too
much throughput fluctuations, initialize all untested rates below tested ones
to the maximum probabilty of higher rates.
Usually this leads to untested lower rates getting initialized with a
probability value of 100%, making them better candidates for fallback without
having to rely on random probing
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -791,14 +791,11 @@ minstrel_ht_calc_rate_stats(struct minst
unsigned int cur_prob;
if (unlikely(mrs->attempts > 0)) {
- mrs->sample_skipped = 0;
cur_prob = MINSTREL_FRAC(mrs->success, mrs->attempts);
minstrel_filter_avg_add(&mrs->prob_avg,
&mrs->prob_avg_1, cur_prob);
mrs->att_hist += mrs->attempts;
mrs->succ_hist += mrs->success;
- } else {
- mrs->sample_skipped++;
}
mrs->last_success = mrs->success;
@@ -851,7 +848,6 @@ minstrel_ht_update_stats(struct minstrel
mi->ampdu_packets = 0;
}
- mi->sample_slow = 0;
mi->sample_count = 0;
memset(tmp_mcs_tp_rate, 0, sizeof(tmp_mcs_tp_rate));
@@ -883,6 +879,7 @@ minstrel_ht_update_stats(struct minstrel
/* Find best rate sets within all MCS groups*/
for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
u16 *tp_rate = tmp_mcs_tp_rate;
+ u16 last_prob = 0;
mg = &mi->groups[group];
if (!mi->supported[group])
@@ -897,7 +894,7 @@ minstrel_ht_update_stats(struct minstrel
if (group == MINSTREL_CCK_GROUP && ht_supported)
tp_rate = tmp_legacy_tp_rate;
- for (i = 0; i < MCS_GROUP_RATES; i++) {
+ for (i = MCS_GROUP_RATES - 1; i >= 0; i--) {
if (!(mi->supported[group] & BIT(i)))
continue;
@@ -906,6 +903,11 @@ minstrel_ht_update_stats(struct minstrel
mrs = &mg->rates[i];
mrs->retry_updated = false;
minstrel_ht_calc_rate_stats(mp, mrs);
+
+ if (mrs->att_hist)
+ last_prob = max(last_prob, mrs->prob_avg);
+ else
+ mrs->prob_avg = max(last_prob, mrs->prob_avg);
cur_prob = mrs->prob_avg;
if (minstrel_ht_get_tp_avg(mi, group, i, cur_prob) == 0)
@@ -1470,13 +1472,9 @@ minstrel_get_sample_rate(struct minstrel
if (sample_dur >= minstrel_get_duration(tp_rate2) &&
(cur_max_tp_streams - 1 <
minstrel_mcs_groups[sample_group].streams ||
- sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
- if (mrs->sample_skipped < 20)
+ sample_dur >= minstrel_get_duration(mi->max_prob_rate)))
return -1;
- if (mi->sample_slow++ > 2)
- return -1;
- }
mi->sample_tries--;
return sample_idx;
--- a/net/mac80211/rc80211_minstrel_ht.h
+++ b/net/mac80211/rc80211_minstrel_ht.h
@@ -123,7 +123,6 @@ struct minstrel_rate_stats {
u8 retry_count;
u8 retry_count_rtscts;
- u8 sample_skipped;
bool retry_updated;
};
@@ -179,7 +178,6 @@ struct minstrel_ht_sta {
u8 sample_wait;
u8 sample_tries;
u8 sample_count;
- u8 sample_slow;
enum minstrel_sample_mode sample_mode;
u16 sample_rate;

767
package/kernel/mac80211/patches/subsys/349-mac80211-minstrel_ht-significantly-redesign-the-rate.patch Normal file
View File

@ -0,0 +1,767 @@
From: Felix Fietkau <nbd@nbd.name>
Date: Fri, 22 Jan 2021 23:57:50 +0100
Subject: [PATCH] mac80211: minstrel_ht: significantly redesign the rate
probing strategy
The biggest flaw in current minstrel_ht is the fact that it needs way too
many probing packets to be able to quickly find the best rate.
Depending on the wifi hardware and operating mode, this can significantly
reduce throughput when not operating at the highest available data rate.
In order to be able to significantly reduce the amount of rate sampling,
we need a much smarter selection of probing rates.
The new approach introduced by this patch maintains a limited set of
available rates to be tested during a statistics window.
They are split into distinct categories:
- MINSTREL_SAMPLE_TYPE_INC - incremental rate upgrade:
Pick the next rate group and find the first rate that is faster than
the current max. throughput rate
- MINSTREL_SAMPLE_TYPE_JUMP - random testing of higher rates:
Pick a random rate from the next group that is faster than the current
max throughput rate. This allows faster adaptation when the link changes
significantly
- MINSTREL_SAMPLE_TYPE_SLOW - test a rate between max_prob, max_tp2 and
max_tp in order to reduce the gap between them
In order to prioritize sampling, every 6 attempts are split into 3x INC,
2x JUMP, 1x SLOW.
Available rates are checked and refilled on every stats window update.
With this approach, we finally get a very small delta in throughput when
comparing setting the optimal data rate as a fixed rate vs normal rate
control operation.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -266,6 +266,14 @@ const struct mcs_group minstrel_mcs_grou
const s16 minstrel_cck_bitrates[4] = { 10, 20, 55, 110 };
const s16 minstrel_ofdm_bitrates[8] = { 60, 90, 120, 180, 240, 360, 480, 540 };
static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly;
+static const u8 minstrel_sample_seq[] = {
+ MINSTREL_SAMPLE_TYPE_INC,
+ MINSTREL_SAMPLE_TYPE_JUMP,
+ MINSTREL_SAMPLE_TYPE_INC,
+ MINSTREL_SAMPLE_TYPE_JUMP,
+ MINSTREL_SAMPLE_TYPE_INC,
+ MINSTREL_SAMPLE_TYPE_SLOW,
+};
static void
minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);
@@ -620,77 +628,31 @@ minstrel_ht_prob_rate_reduce_streams(str
}
}
-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)
+static u16
+__minstrel_ht_get_sample_rate(struct minstrel_ht_sta *mi,
+ enum minstrel_sample_type type)
{
- const struct mcs_group *group, *tp_group;
- int i, g, max_dur;
- int tp_idx;
-
- tp_group = &minstrel_mcs_groups[MI_RATE_GROUP(mi->max_tp_rate[0])];
- tp_idx = MI_RATE_IDX(mi->max_tp_rate[0]);
-
- 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;
+ u16 *rates = mi->sample[type].sample_rates;
+ u16 cur;
+ int i;
- group = &minstrel_mcs_groups[g];
- if (!minstrel_ht_probe_group(mi, tp_group, tp_idx, group))
+ for (i = 0; i < MINSTREL_SAMPLE_RATES; i++) {
+ if (!rates[i])
continue;
- for (i = 0; supported; supported >>= 1, i++) {
- int idx;
-
- if (!(supported & 1))
- continue;
-
- if ((group->duration[i] << group->shift) > max_dur)
- continue;
-
- idx = MI_RATE(g, i);
- if (idx == mi->max_tp_rate[0])
- continue;
-
- rates[(*n_rates)++] = idx;
- break;
- }
+ cur = rates[i];
+ rates[i] = 0;
+ return cur;
}
+
+ return 0;
}
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;
+ u16 rate;
/*
* Use rate switching instead of probing packets for devices with
@@ -699,43 +661,11 @@ minstrel_ht_rate_sample_switch(struct mi
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_avg > 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_RATE_GROUP(mi->max_tp_rate[0]);
- u16 supported = mi->supported[g_idx];
-
- supported >>= MI_RATE_IDX(mi->max_tp_rate[0]);
- for (i = 0; supported; supported >>= 1, i++) {
- if (!(supported & 1))
- continue;
-
- probe_rate = mi->max_tp_rate[0] + i;
- goto out;
- }
-
+ rate = __minstrel_ht_get_sample_rate(mi, MINSTREL_SAMPLE_TYPE_INC);
+ if (!rate)
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_rate = rate;
mi->sample_mode = MINSTREL_SAMPLE_ACTIVE;
}
@@ -804,6 +734,274 @@ minstrel_ht_calc_rate_stats(struct minst
mrs->attempts = 0;
}
+static bool
+minstrel_ht_find_sample_rate(struct minstrel_ht_sta *mi, int type, int idx)
+{
+ int i;
+
+ for (i = 0; i < MINSTREL_SAMPLE_RATES; i++) {
+ u16 cur = mi->sample[type].sample_rates[i];
+
+ if (cur == idx)
+ return true;
+
+ if (!cur)
+ break;
+ }
+
+ return false;
+}
+
+static int
+minstrel_ht_move_sample_rates(struct minstrel_ht_sta *mi, int type,
+ u32 fast_rate_dur, u32 slow_rate_dur)
+{
+ u16 *rates = mi->sample[type].sample_rates;
+ int i, j;
+
+ for (i = 0, j = 0; i < MINSTREL_SAMPLE_RATES; i++) {
+ u32 duration;
+ bool valid = false;
+ u16 cur;
+
+ cur = rates[i];
+ if (!cur)
+ continue;
+
+ duration = minstrel_get_duration(cur);
+ switch (type) {
+ case MINSTREL_SAMPLE_TYPE_SLOW:
+ valid = duration > fast_rate_dur &&
+ duration < slow_rate_dur;
+ break;
+ case MINSTREL_SAMPLE_TYPE_INC:
+ case MINSTREL_SAMPLE_TYPE_JUMP:
+ valid = duration < fast_rate_dur;
+ break;
+ default:
+ valid = false;
+ break;
+ }
+
+ if (!valid) {
+ rates[i] = 0;
+ continue;
+ }
+
+ if (i == j)
+ continue;
+
+ rates[j++] = cur;
+ rates[i] = 0;
+ }
+
+ return j;
+}
+
+static int
+minstrel_ht_group_min_rate_offset(struct minstrel_ht_sta *mi, int group,
+ u32 max_duration)
+{
+ u16 supported = mi->supported[group];
+ int i;
+
+ for (i = 0; i < MCS_GROUP_RATES && supported; i++, supported >>= 1) {
+ if (!(supported & BIT(0)))
+ continue;
+
+ if (minstrel_get_duration(MI_RATE(group, i)) >= max_duration)
+ continue;
+
+ return i;
+ }
+
+ return -1;
+}
+
+/*
+ * Incremental update rates:
+ * Flip through groups and pick the first group rate that is faster than the
+ * highest currently selected rate
+ */
+static u16
+minstrel_ht_next_inc_rate(struct minstrel_ht_sta *mi, u32 fast_rate_dur)
+{
+ struct minstrel_mcs_group_data *mg;
+ u8 type = MINSTREL_SAMPLE_TYPE_INC;
+ int i, index = 0;
+ u8 group;
+
+ group = mi->sample[type].sample_group;
+ for (i = 0; i < ARRAY_SIZE(minstrel_mcs_groups); i++) {
+ group = (group + 1) % ARRAY_SIZE(minstrel_mcs_groups);
+ mg = &mi->groups[group];
+
+ index = minstrel_ht_group_min_rate_offset(mi, group,
+ fast_rate_dur);
+ if (index < 0)
+ continue;
+
+ index = MI_RATE(group, index & 0xf);
+ if (!minstrel_ht_find_sample_rate(mi, type, index))
+ goto out;
+ }
+ index = 0;
+
+out:
+ mi->sample[type].sample_group = group;
+
+ return index;
+}
+
+static int
+minstrel_ht_next_group_sample_rate(struct minstrel_ht_sta *mi, int group,
+ u16 supported, int offset)
+{
+ struct minstrel_mcs_group_data *mg = &mi->groups[group];
+ u16 idx;
+ int i;
+
+ for (i = 0; i < MCS_GROUP_RATES; i++) {
+ idx = sample_table[mg->column][mg->index];
+ if (++mg->index >= MCS_GROUP_RATES) {
+ mg->index = 0;
+ if (++mg->column >= ARRAY_SIZE(sample_table))
+ mg->column = 0;
+ }
+
+ if (idx < offset)
+ continue;
+
+ if (!(supported & BIT(idx)))
+ continue;
+
+ return MI_RATE(group, idx);
+ }
+
+ return -1;
+}
+
+/*
+ * Jump rates:
+ * Sample random rates, use those that are faster than the highest
+ * currently selected rate. Rates between the fastest and the slowest
+ * get sorted into the slow sample bucket, but only if it has room
+ */
+static u16
+minstrel_ht_next_jump_rate(struct minstrel_ht_sta *mi, u32 fast_rate_dur,
+ u32 slow_rate_dur, int *slow_rate_ofs)
+{
+ struct minstrel_mcs_group_data *mg;
+ struct minstrel_rate_stats *mrs;
+ u32 max_duration = slow_rate_dur;
+ int i, index, offset;
+ u16 *slow_rates;
+ u16 supported;
+ u32 duration;
+ u8 group;
+
+ if (*slow_rate_ofs >= MINSTREL_SAMPLE_RATES)
+ max_duration = fast_rate_dur;
+
+ slow_rates = mi->sample[MINSTREL_SAMPLE_TYPE_SLOW].sample_rates;
+ group = mi->sample[MINSTREL_SAMPLE_TYPE_JUMP].sample_group;
+ for (i = 0; i < ARRAY_SIZE(minstrel_mcs_groups); i++) {
+ u8 type;
+
+ group = (group + 1) % ARRAY_SIZE(minstrel_mcs_groups);
+ mg = &mi->groups[group];
+
+ supported = mi->supported[group];
+ if (!supported)
+ continue;
+
+ offset = minstrel_ht_group_min_rate_offset(mi, group,
+ max_duration);
+ if (offset < 0)
+ continue;
+
+ index = minstrel_ht_next_group_sample_rate(mi, group, supported,
+ offset);
+ if (index < 0)
+ continue;
+
+ duration = minstrel_get_duration(index);
+ if (duration < fast_rate_dur)
+ type = MINSTREL_SAMPLE_TYPE_JUMP;
+ else
+ type = MINSTREL_SAMPLE_TYPE_SLOW;
+
+ if (minstrel_ht_find_sample_rate(mi, type, index))
+ continue;
+
+ if (type == MINSTREL_SAMPLE_TYPE_JUMP)
+ goto found;
+
+ if (*slow_rate_ofs >= MINSTREL_SAMPLE_RATES)
+ continue;
+
+ if (duration >= slow_rate_dur)
+ continue;
+
+ /* skip slow rates with high success probability */
+ mrs = minstrel_get_ratestats(mi, index);
+ if (mrs->prob_avg > MINSTREL_FRAC(95, 100))
+ continue;
+
+ slow_rates[(*slow_rate_ofs)++] = index;
+ if (*slow_rate_ofs >= MINSTREL_SAMPLE_RATES)
+ max_duration = fast_rate_dur;
+ }
+ index = 0;
+
+found:
+ mi->sample[MINSTREL_SAMPLE_TYPE_JUMP].sample_group = group;
+
+ return index;
+}
+
+static void
+minstrel_ht_refill_sample_rates(struct minstrel_ht_sta *mi)
+{
+ u32 prob_dur = minstrel_get_duration(mi->max_prob_rate);
+ u32 tp_dur = minstrel_get_duration(mi->max_tp_rate[0]);
+ u32 tp2_dur = minstrel_get_duration(mi->max_tp_rate[1]);
+ u32 fast_rate_dur = min(min(tp_dur, tp2_dur), prob_dur);
+ u32 slow_rate_dur = max(max(tp_dur, tp2_dur), prob_dur);
+ u16 *rates;
+ int i, j;
+
+ rates = mi->sample[MINSTREL_SAMPLE_TYPE_INC].sample_rates;
+ i = minstrel_ht_move_sample_rates(mi, MINSTREL_SAMPLE_TYPE_INC,
+ fast_rate_dur, slow_rate_dur);
+ while (i < MINSTREL_SAMPLE_RATES) {
+ rates[i] = minstrel_ht_next_inc_rate(mi, tp_dur);
+ if (!rates[i])
+ break;
+
+ i++;
+ }
+
+ rates = mi->sample[MINSTREL_SAMPLE_TYPE_JUMP].sample_rates;
+ i = minstrel_ht_move_sample_rates(mi, MINSTREL_SAMPLE_TYPE_JUMP,
+ fast_rate_dur, slow_rate_dur);
+ j = minstrel_ht_move_sample_rates(mi, MINSTREL_SAMPLE_TYPE_SLOW,
+ fast_rate_dur, slow_rate_dur);
+ while (i < MINSTREL_SAMPLE_RATES) {
+ rates[i] = minstrel_ht_next_jump_rate(mi, fast_rate_dur,
+ slow_rate_dur, &j);
+ if (!rates[i])
+ break;
+
+ i++;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(mi->sample); i++)
+ memcpy(mi->sample[i].cur_sample_rates, mi->sample[i].sample_rates,
+ sizeof(mi->sample[i].cur_sample_rates));
+}
+
+
/*
* Update rate statistics and select new primary rates
*
@@ -848,8 +1046,6 @@ minstrel_ht_update_stats(struct minstrel
mi->ampdu_packets = 0;
}
- mi->sample_count = 0;
-
memset(tmp_mcs_tp_rate, 0, sizeof(tmp_mcs_tp_rate));
memset(tmp_legacy_tp_rate, 0, sizeof(tmp_legacy_tp_rate));
@@ -885,8 +1081,6 @@ minstrel_ht_update_stats(struct minstrel
if (!mi->supported[group])
continue;
- mi->sample_count++;
-
/* (re)Initialize group rate indexes */
for(j = 0; j < MAX_THR_RATES; j++)
tmp_group_tp_rate[j] = MI_RATE(group, 0);
@@ -953,9 +1147,7 @@ minstrel_ht_update_stats(struct minstrel
/* Try to increase robustness of max_prob_rate*/
minstrel_ht_prob_rate_reduce_streams(mi);
-
- /* try to sample half of all available rates during each interval */
- mi->sample_count *= 4;
+ minstrel_ht_refill_sample_rates(mi);
if (sample)
minstrel_ht_rate_sample_switch(mp, mi);
@@ -972,6 +1164,7 @@ minstrel_ht_update_stats(struct minstrel
/* Reset update timer */
mi->last_stats_update = jiffies;
+ mi->sample_time = jiffies;
}
static bool
@@ -1002,28 +1195,6 @@ minstrel_ht_txstat_valid(struct minstrel
}
static void
-minstrel_set_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 (!mi->supported[mi->sample_group])
- 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, u16 *idx, bool primary)
{
int group, orig_group;
@@ -1108,14 +1279,6 @@ minstrel_ht_tx_status(void *priv, struct
mi->ampdu_packets++;
mi->ampdu_len += info->status.ampdu_len;
- if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
- int avg_ampdu_len = minstrel_ht_avg_ampdu_len(mi);
-
- mi->sample_wait = 16 + 2 * avg_ampdu_len;
- mi->sample_tries = 1;
- mi->sample_count--;
- }
-
if (mi->sample_mode != MINSTREL_SAMPLE_IDLE)
rate_sample = minstrel_get_ratestats(mi, mi->sample_rate);
@@ -1387,97 +1550,20 @@ minstrel_ht_update_rates(struct minstrel
rate_control_set_rates(mp->hw, mi->sta, rates);
}
-static int
-minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
+static u16
+minstrel_ht_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
{
- struct minstrel_rate_stats *mrs;
- struct minstrel_mcs_group_data *mg;
- unsigned int sample_dur, sample_group, cur_max_tp_streams;
- 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;
- }
-
- if (!mi->sample_tries)
- return -1;
-
- sample_group = mi->sample_group;
- mg = &mi->groups[sample_group];
- sample_idx = sample_table[mg->column][mg->index];
- minstrel_set_next_sample_idx(mi);
-
- if (!(mi->supported[sample_group] & BIT(sample_idx)))
- return -1;
-
- mrs = &mg->rates[sample_idx];
- sample_idx += MI_RATE(sample_group, 0);
-
- tp_rate1 = mi->max_tp_rate[0];
+ u8 seq;
- /* Set tp_rate2 to the second highest max_tp_rate */
- if (minstrel_get_duration(mi->max_tp_rate[0]) >
- minstrel_get_duration(mi->max_tp_rate[1])) {
- tp_rate2 = mi->max_tp_rate[0];
+ if (mp->hw->max_rates > 1) {
+ seq = mi->sample_seq;
+ mi->sample_seq = (seq + 1) % ARRAY_SIZE(minstrel_sample_seq);
+ seq = minstrel_sample_seq[seq];
} else {
- tp_rate2 = mi->max_tp_rate[1];
+ seq = MINSTREL_SAMPLE_TYPE_INC;
}
- /*
- * Sampling might add some overhead (RTS, no aggregation)
- * to the frame. Hence, don't use sampling for the highest currently
- * used highest throughput or probability rate.
- */
- if (sample_idx == mi->max_tp_rate[0] || sample_idx == mi->max_prob_rate)
- return -1;
-
- /*
- * Do not sample if the probability is already higher than 95%,
- * or if the rate is 3 times slower than the current max probability
- * rate, to avoid wasting airtime.
- */
- sample_dur = minstrel_get_duration(sample_idx);
- if (mrs->prob_avg > MINSTREL_FRAC(95, 100) ||
- 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.
- */
-
- cur_max_tp_streams = minstrel_mcs_groups[MI_RATE_GROUP(tp_rate1)].streams;
- if (sample_dur >= minstrel_get_duration(tp_rate2) &&
- (cur_max_tp_streams - 1 <
- minstrel_mcs_groups[sample_group].streams ||
- sample_dur >= minstrel_get_duration(mi->max_prob_rate)))
- return -1;
-
- mi->sample_tries--;
-
- return sample_idx;
+ return __minstrel_ht_get_sample_rate(mi, seq);
}
static void
@@ -1489,7 +1575,7 @@ minstrel_ht_get_rate(void *priv, struct
struct ieee80211_tx_rate *rate = &info->status.rates[0];
struct minstrel_ht_sta *mi = priv_sta;
struct minstrel_priv *mp = priv;
- int sample_idx;
+ u16 sample_idx;
if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&
!minstrel_ht_is_legacy_group(MI_RATE_GROUP(mi->max_prob_rate)))
@@ -1505,11 +1591,19 @@ minstrel_ht_get_rate(void *priv, struct
/* Don't use EAPOL frames for sampling on non-mrr hw */
if (mp->hw->max_rates == 1 &&
(info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
- sample_idx = -1;
- else
- sample_idx = minstrel_get_sample_rate(mp, mi);
+ return;
- if (sample_idx < 0)
+ if (mp->hw->max_rates == 1 && mp->sample_switch &&
+ (mi->total_packets_cur >= SAMPLE_SWITCH_THR ||
+ mp->sample_switch == 1))
+ return;
+
+ if (time_is_before_jiffies(mi->sample_time))
+ return;
+
+ mi->sample_time = jiffies + MINSTREL_SAMPLE_INTERVAL;
+ sample_idx = minstrel_ht_get_sample_rate(mp, mi);
+ if (!sample_idx)
return;
sample_group = &minstrel_mcs_groups[MI_RATE_GROUP(sample_idx)];
@@ -1630,16 +1724,6 @@ minstrel_ht_update_caps(void *priv, stru
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;
-
if (!use_vht) {
stbc = (ht_cap & IEEE80211_HT_CAP_RX_STBC) >>
IEEE80211_HT_CAP_RX_STBC_SHIFT;
--- a/net/mac80211/rc80211_minstrel_ht.h
+++ b/net/mac80211/rc80211_minstrel_ht.h
@@ -69,6 +69,8 @@
#define MI_RATE_IDX(_rate) FIELD_GET(MI_RATE_IDX_MASK, _rate)
#define MI_RATE_GROUP(_rate) FIELD_GET(MI_RATE_GROUP_MASK, _rate)
+#define MINSTREL_SAMPLE_RATES 5 /* rates per sample type */
+#define MINSTREL_SAMPLE_INTERVAL (HZ / 50)
struct minstrel_priv {
struct ieee80211_hw *hw;
@@ -126,6 +128,13 @@ struct minstrel_rate_stats {
bool retry_updated;
};
+enum minstrel_sample_type {
+ MINSTREL_SAMPLE_TYPE_INC,
+ MINSTREL_SAMPLE_TYPE_JUMP,
+ MINSTREL_SAMPLE_TYPE_SLOW,
+ __MINSTREL_SAMPLE_TYPE_MAX
+};
+
struct minstrel_mcs_group_data {
u8 index;
u8 column;
@@ -144,6 +153,12 @@ enum minstrel_sample_mode {
MINSTREL_SAMPLE_PENDING,
};
+struct minstrel_sample_category {
+ u8 sample_group;
+ u16 sample_rates[MINSTREL_SAMPLE_RATES];
+ u16 cur_sample_rates[MINSTREL_SAMPLE_RATES];
+};
+
struct minstrel_ht_sta {
struct ieee80211_sta *sta;
@@ -175,16 +190,14 @@ struct minstrel_ht_sta {
/* tx flags to add for frames for this sta */
u32 tx_flags;
- u8 sample_wait;
- u8 sample_tries;
- u8 sample_count;
+ unsigned long sample_time;
+ struct minstrel_sample_category sample[__MINSTREL_SAMPLE_TYPE_MAX];
+
+ u8 sample_seq;
enum minstrel_sample_mode sample_mode;
u16 sample_rate;
- /* current MCS group to be sampled */
- u8 sample_group;
-
u8 band;
/* Bitfield of supported MCS rates of all groups */

59
package/kernel/mac80211/patches/subsys/350-mac80211-minstrel_ht-show-sampling-rates-in-debugfs.patch Normal file
View File

@ -0,0 +1,59 @@
From: Felix Fietkau <nbd@nbd.name>
Date: Sat, 23 Jan 2021 00:10:34 +0100
Subject: [PATCH] mac80211: minstrel_ht: show sampling rates in debugfs
This makes it easier to see what rates are going to be tested next
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/net/mac80211/rc80211_minstrel_ht_debugfs.c
+++ b/net/mac80211/rc80211_minstrel_ht_debugfs.c
@@ -32,6 +32,18 @@ minstrel_stats_release(struct inode *ino
return 0;
}
+static bool
+minstrel_ht_is_sample_rate(struct minstrel_ht_sta *mi, int idx)
+{
+ int type, i;
+
+ for (type = 0; type < ARRAY_SIZE(mi->sample); type++)
+ for (i = 0; i < MINSTREL_SAMPLE_RATES; i++)
+ if (mi->sample[type].cur_sample_rates[i] == idx)
+ return true;
+ return false;
+}
+
static char *
minstrel_ht_stats_dump(struct minstrel_ht_sta *mi, int i, char *p)
{
@@ -84,6 +96,7 @@ minstrel_ht_stats_dump(struct minstrel_h
*(p++) = (idx == mi->max_tp_rate[2]) ? 'C' : ' ';
*(p++) = (idx == mi->max_tp_rate[3]) ? 'D' : ' ';
*(p++) = (idx == mi->max_prob_rate) ? 'P' : ' ';
+ *(p++) = minstrel_ht_is_sample_rate(mi, idx) ? 'S' : ' ';
if (gflags & IEEE80211_TX_RC_MCS) {
p += sprintf(p, " MCS%-2u", (mg->streams - 1) * 8 + j);
@@ -145,9 +158,9 @@ minstrel_ht_stats_open(struct inode *ino
p += sprintf(p, "\n");
p += sprintf(p,
- " best ____________rate__________ ____statistics___ _____last____ ______sum-of________\n");
+ " best ____________rate__________ ____statistics___ _____last____ ______sum-of________\n");
p += sprintf(p,
- "mode guard # rate [name idx airtime max_tp] [avg(tp) avg(prob)] [retry|suc|att] [#success | #attempts]\n");
+ "mode guard # rate [name idx airtime max_tp] [avg(tp) avg(prob)] [retry|suc|att] [#success | #attempts]\n");
p = minstrel_ht_stats_dump(mi, MINSTREL_CCK_GROUP, p);
for (i = 0; i < MINSTREL_CCK_GROUP; i++)
@@ -228,6 +241,8 @@ minstrel_ht_stats_csv_dump(struct minstr
p += sprintf(p, "%s" ,((idx == mi->max_tp_rate[2]) ? "C" : ""));
p += sprintf(p, "%s" ,((idx == mi->max_tp_rate[3]) ? "D" : ""));
p += sprintf(p, "%s" ,((idx == mi->max_prob_rate) ? "P" : ""));
+ p += sprintf(p, "%s" ,((idx == mi->max_prob_rate) ? "P" : ""));
+ p += sprintf(p, "%s", (minstrel_ht_is_sample_rate(mi, idx) ? "S" : ""));
if (gflags & IEEE80211_TX_RC_MCS) {
p += sprintf(p, ",MCS%-2u,", (mg->streams - 1) * 8 + j);

279
package/kernel/mac80211/patches/subsys/351-mac80211-minstrel_ht-remove-sample-rate-switching-co.patch Normal file
View File

@ -0,0 +1,279 @@
From: Felix Fietkau <nbd@nbd.name>
Date: Sat, 23 Jan 2021 07:18:26 +0100
Subject: [PATCH] mac80211: minstrel_ht: remove sample rate switching code for
constrained devices
This was added to mitigate the effects of too much sampling on devices that
use a static global fallback table instead of configurable multi-rate retry.
Now that the sampling algorithm is improved, this code path no longer performs
any better than the standard probing on affected devices.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -648,27 +648,6 @@ __minstrel_ht_get_sample_rate(struct min
return 0;
}
-static void
-minstrel_ht_rate_sample_switch(struct minstrel_priv *mp,
- struct minstrel_ht_sta *mi)
-{
- u16 rate;
-
- /*
- * Use rate switching instead of probing packets for devices with
- * little control over retry fallback behavior
- */
- if (mp->hw->max_rates > 1)
- return;
-
- rate = __minstrel_ht_get_sample_rate(mi, MINSTREL_SAMPLE_TYPE_INC);
- if (!rate)
- return;
-
- mi->sample_rate = rate;
- mi->sample_mode = MINSTREL_SAMPLE_ACTIVE;
-}
-
static inline int
minstrel_ewma(int old, int new, int weight)
{
@@ -1012,8 +991,7 @@ minstrel_ht_refill_sample_rates(struct m
* 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,
- bool sample)
+minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
{
struct minstrel_mcs_group_data *mg;
struct minstrel_rate_stats *mrs;
@@ -1023,18 +1001,6 @@ minstrel_ht_update_stats(struct minstrel
u16 index;
bool ht_supported = mi->sta->ht_cap.ht_supported;
- 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,
@@ -1149,16 +1115,12 @@ minstrel_ht_update_stats(struct minstrel
minstrel_ht_prob_rate_reduce_streams(mi);
minstrel_ht_refill_sample_rates(mi);
- if (sample)
- minstrel_ht_rate_sample_switch(mp, mi);
-
#ifdef CPTCFG_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
@@ -1248,11 +1210,10 @@ minstrel_ht_tx_status(void *priv, struct
struct ieee80211_tx_info *info = st->info;
struct minstrel_ht_sta *mi = priv_sta;
struct ieee80211_tx_rate *ar = info->status.rates;
- struct minstrel_rate_stats *rate, *rate2, *rate_sample = NULL;
+ struct minstrel_rate_stats *rate, *rate2;
struct minstrel_priv *mp = priv;
u32 update_interval = mp->update_interval;
bool last, update = false;
- bool sample_status = false;
int i;
/* This packet was aggregated but doesn't carry status info */
@@ -1279,49 +1240,18 @@ minstrel_ht_tx_status(void *priv, struct
mi->ampdu_packets++;
mi->ampdu_len += 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, mi, &ar[0]);
for (i = 0; !last; i++) {
last = (i == IEEE80211_TX_MAX_RATES - 1) ||
!minstrel_ht_txstat_valid(mp, mi, &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;
}
- switch (mi->sample_mode) {
- case MINSTREL_SAMPLE_IDLE:
- if (mp->hw->max_rates > 1 ||
- mi->total_packets_cur < SAMPLE_SWITCH_THR)
- update_interval /= 2;
- 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;
-
- update = true;
- minstrel_ht_update_stats(mp, mi, false);
- break;
- }
-
-
if (mp->hw->max_rates > 1) {
/*
* check for sudden death of spatial multiplexing,
@@ -1344,7 +1274,7 @@ minstrel_ht_tx_status(void *priv, struct
if (time_after(jiffies, mi->last_stats_update + update_interval)) {
update = true;
- minstrel_ht_update_stats(mp, mi, true);
+ minstrel_ht_update_stats(mp, mi);
}
if (update)
@@ -1523,18 +1453,14 @@ static void
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++, first_rate);
+ minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]);
if (mp->hw->max_rates >= 3) {
/* At least 3 tx rates supported, use max_tp_rate[1] next */
@@ -1593,11 +1519,6 @@ minstrel_ht_get_rate(void *priv, struct
(info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
return;
- if (mp->hw->max_rates == 1 && mp->sample_switch &&
- (mi->total_packets_cur >= SAMPLE_SWITCH_THR ||
- mp->sample_switch == 1))
- return;
-
if (time_is_before_jiffies(mi->sample_time))
return;
@@ -1811,7 +1732,7 @@ minstrel_ht_update_caps(void *priv, stru
minstrel_ht_update_ofdm(mp, mi, sband, sta);
/* create an initial rate table with the lowest supported rates */
- minstrel_ht_update_stats(mp, mi, true);
+ minstrel_ht_update_stats(mp, mi);
minstrel_ht_update_rates(mp, mi);
}
@@ -1927,8 +1848,6 @@ minstrel_ht_alloc(struct ieee80211_hw *h
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 */
@@ -1948,7 +1867,7 @@ minstrel_ht_alloc(struct ieee80211_hw *h
mp->has_mrr = true;
mp->hw = hw;
- mp->update_interval = HZ / 10;
+ mp->update_interval = HZ / 20;
minstrel_ht_init_cck_rates(mp);
for (i = 0; i < ARRAY_SIZE(mp->hw->wiphy->bands); i++)
@@ -1966,8 +1885,6 @@ static void minstrel_ht_add_debugfs(stru
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
--- a/net/mac80211/rc80211_minstrel_ht.h
+++ b/net/mac80211/rc80211_minstrel_ht.h
@@ -75,7 +75,6 @@
struct minstrel_priv {
struct ieee80211_hw *hw;
bool has_mrr;
- u32 sample_switch;
unsigned int cw_min;
unsigned int cw_max;
unsigned int max_retry;
@@ -147,12 +146,6 @@ struct minstrel_mcs_group_data {
struct minstrel_rate_stats rates[MCS_GROUP_RATES];
};
-enum minstrel_sample_mode {
- MINSTREL_SAMPLE_IDLE,
- MINSTREL_SAMPLE_ACTIVE,
- MINSTREL_SAMPLE_PENDING,
-};
-
struct minstrel_sample_category {
u8 sample_group;
u16 sample_rates[MINSTREL_SAMPLE_RATES];
@@ -182,23 +175,19 @@ struct minstrel_ht_sta {
unsigned int overhead_legacy;
unsigned int overhead_legacy_rtscts;
- unsigned int total_packets_last;
- unsigned int total_packets_cur;
unsigned int total_packets;
unsigned int sample_packets;
/* tx flags to add for frames for this sta */
u32 tx_flags;
- unsigned long sample_time;
- struct minstrel_sample_category sample[__MINSTREL_SAMPLE_TYPE_MAX];
+ u8 band;
u8 sample_seq;
-
- enum minstrel_sample_mode sample_mode;
u16 sample_rate;
- u8 band;
+ unsigned long sample_time;
+ struct minstrel_sample_category sample[__MINSTREL_SAMPLE_TYPE_MAX];
/* Bitfield of supported MCS rates of all groups */
u16 supported[MINSTREL_GROUPS_NB];