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mac80211: minstrel_ht: use bitfields to encode rate indexes
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Get rid of a lot of divisions and modulo operations
Reduces code size and improves performance

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210127055735.78599-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Felix Fietkau authored and Johannes Berg committed Feb 12, 2021
1 parent 9e6d512 commit a42fa25
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Showing 3 changed files with 79 additions and 64 deletions.
126 changes: 64 additions & 62 deletions net/mac80211/rc80211_minstrel_ht.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -379,13 +379,13 @@ minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
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)
{
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;
}
Expand All @@ -398,7 +398,7 @@ minstrel_ht_avg_ampdu_len(struct minstrel_ht_sta *mi)
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]);
Expand Down Expand Up @@ -465,14 +465,14 @@ minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u16 index,
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);
Expand Down Expand Up @@ -504,23 +504,23 @@ minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 *dest, u16 index)
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;

Expand All @@ -529,8 +529,8 @@ minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 *dest, u16 index)
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)) {
Expand Down Expand Up @@ -567,13 +567,13 @@ minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta *mi,
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);

Expand All @@ -600,14 +600,14 @@ minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi)
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) &&
Expand Down Expand Up @@ -644,8 +644,8 @@ minstrel_ht_find_probe_rates(struct minstrel_ht_sta *mi, u16 *rates, int *n_rate
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)
Expand All @@ -670,7 +670,7 @@ minstrel_ht_find_probe_rates(struct minstrel_ht_sta *mi, u16 *rates, int *n_rate
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;

Expand Down Expand Up @@ -712,10 +712,10 @@ minstrel_ht_rate_sample_switch(struct minstrel_priv *mp,

/* 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;
Expand Down Expand Up @@ -854,24 +854,27 @@ minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
mi->sample_slow = 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));
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;
else
group = 0;

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;
Expand All @@ -888,7 +891,7 @@ minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,

/* (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;
Expand All @@ -897,7 +900,7 @@ minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
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;
Expand Down Expand Up @@ -929,13 +932,13 @@ minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
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,
Expand Down Expand Up @@ -1022,7 +1025,7 @@ minstrel_downgrade_rate(struct minstrel_ht_sta *mi, u16 *idx, bool primary)
{
int group, orig_group;

orig_group = group = *idx / MCS_GROUP_RATES;
orig_group = group = MI_RATE_GROUP(*idx);
while (group > 0) {
group--;

Expand Down Expand Up @@ -1206,7 +1209,7 @@ minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
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 {
Expand Down Expand Up @@ -1239,7 +1242,7 @@ 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;
Expand All @@ -1259,7 +1262,7 @@ minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
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)
Expand Down Expand Up @@ -1289,17 +1292,17 @@ minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
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 */
Expand Down Expand Up @@ -1405,7 +1408,7 @@ minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
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];

Expand Down Expand Up @@ -1455,8 +1458,7 @@ minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
* 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 ||
Expand Down Expand Up @@ -1484,7 +1486,7 @@ minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
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;
Expand Down Expand Up @@ -1512,8 +1514,8 @@ minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
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)
Expand All @@ -1529,7 +1531,7 @@ minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
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;
Expand Down Expand Up @@ -1898,8 +1900,8 @@ static u32 minstrel_ht_get_expected_throughput(void *priv_sta)
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 */
Expand Down
13 changes: 13 additions & 0 deletions net/mac80211/rc80211_minstrel_ht.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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 */
Expand Down Expand Up @@ -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;
Expand Down
4 changes: 2 additions & 2 deletions net/mac80211/rc80211_minstrel_ht_debugfs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -56,7 +56,7 @@ minstrel_ht_stats_dump(struct minstrel_ht_sta *mi, int i, char *p)

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)))
Expand Down Expand Up @@ -201,7 +201,7 @@ minstrel_ht_stats_csv_dump(struct minstrel_ht_sta *mi, int i, char *p)

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)))
Expand Down

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