openwrt/package/kernel/mac80211/patches/subsys/346-mac80211-minstrel_ht-use-bitfields-to-encode-rate-in.patch

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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)))