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mac80211: restructure per-rate throughput calculation into function
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This patch moves Minstrels and Minstrel-HTs per-rate throughput
calculation (EWMA(thr)) into a dedicated function to be called.
Therefore the variable "unsigned int cur_tp" within struct
"minstrel_rate_stats" becomes obsolete.  and is removed to free
up its space.

Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de>
Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Thomas Huehn authored and Johannes Berg committed Apr 1, 2015
1 parent 9134073 commit 6a27b2c
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Showing 6 changed files with 88 additions and 61 deletions.
43 changes: 28 additions & 15 deletions net/mac80211/rc80211_minstrel.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -69,14 +69,32 @@ rix_to_ndx(struct minstrel_sta_info *mi, int rix)
return i;
}

/* return current EMWA throughput */
int minstrel_get_tp_avg(struct minstrel_rate *mr)
{
int usecs;

usecs = mr->perfect_tx_time;
if (!usecs)
usecs = 1000000;

/* reset thr. below 10% success */
if (mr->stats.prob_ewma < MINSTREL_FRAC(10, 100))
return 0;
else
return MINSTREL_TRUNC(mr->stats.prob_ewma * (100000 / usecs));
}

/* find & sort topmost throughput rates */
static inline void
minstrel_sort_best_tp_rates(struct minstrel_sta_info *mi, int i, u8 *tp_list)
{
int j = MAX_THR_RATES;

while (j > 0 && mi->r[i].stats.cur_tp > mi->r[tp_list[j - 1]].stats.cur_tp)
while (j > 0 && (minstrel_get_tp_avg(&mi->r[i]) >
minstrel_get_tp_avg(&mi->r[tp_list[j - 1]])))
j--;

if (j < MAX_THR_RATES - 1)
memmove(&tp_list[j + 1], &tp_list[j], MAX_THR_RATES - (j + 1));
if (j < MAX_THR_RATES)
Expand Down Expand Up @@ -158,8 +176,7 @@ minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
{
u8 tmp_tp_rate[MAX_THR_RATES];
u8 tmp_prob_rate = 0;
u32 usecs;
int i;
int i, tmp_cur_tp, tmp_prob_tp;

for (i = 0; i < MAX_THR_RATES; i++)
tmp_tp_rate[i] = 0;
Expand All @@ -168,19 +185,9 @@ minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
struct minstrel_rate *mr = &mi->r[i];
struct minstrel_rate_stats *mrs = &mi->r[i].stats;

usecs = mr->perfect_tx_time;
if (!usecs)
usecs = 1000000;

/* Update success probabilities per rate */
minstrel_calc_rate_stats(mrs);

/* Update throughput per rate, reset thr. below 10% success */
if (mrs->prob_ewma < MINSTREL_FRAC(10, 100))
mrs->cur_tp = 0;
else
mrs->cur_tp = mrs->prob_ewma * (1000000 / usecs);

/* Sample less often below the 10% chance of success.
* Sample less often above the 95% chance of success. */
if (mrs->prob_ewma > MINSTREL_FRAC(95, 100) ||
Expand All @@ -205,7 +212,9 @@ minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
* (2) if all success probabilities < 95%, the rate with
* highest success probability is chosen as max_prob_rate */
if (mrs->prob_ewma >= MINSTREL_FRAC(95, 100)) {
if (mrs->cur_tp >= mi->r[tmp_prob_rate].stats.cur_tp)
tmp_cur_tp = minstrel_get_tp_avg(mr);
tmp_prob_tp = minstrel_get_tp_avg(&mi->r[tmp_prob_rate]);
if (tmp_cur_tp >= tmp_prob_tp)
tmp_prob_rate = i;
} else {
if (mrs->prob_ewma >= mi->r[tmp_prob_rate].stats.prob_ewma)
Expand Down Expand Up @@ -676,11 +685,15 @@ static u32 minstrel_get_expected_throughput(void *priv_sta)
{
struct minstrel_sta_info *mi = priv_sta;
int idx = mi->max_tp_rate[0];
int tmp_cur_tp;

/* convert pkt per sec in kbps (1200 is the average pkt size used for
* computing cur_tp
*/
return MINSTREL_TRUNC(mi->r[idx].stats.cur_tp) * 1200 * 8 / 1024;
tmp_cur_tp = minstrel_get_tp_avg(&mi->r[idx]);
tmp_cur_tp = tmp_cur_tp * 1200 * 8 / 1024;

return tmp_cur_tp;
}

const struct rate_control_ops mac80211_minstrel = {
Expand Down
4 changes: 1 addition & 3 deletions net/mac80211/rc80211_minstrel.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -38,9 +38,6 @@ struct minstrel_rate_stats {
/* total attempts/success counters */
u64 att_hist, succ_hist;

/* current EWMA of rate throughput */
unsigned int cur_tp;

/* statistis of packet delivery probability
* cur_prob - current prob within last update intervall
* prob_ewma - exponential weighted moving average of prob */
Expand Down Expand Up @@ -137,6 +134,7 @@ void minstrel_remove_sta_debugfs(void *priv, void *priv_sta);

/* Recalculate success probabilities and counters for a given rate using EWMA */
void minstrel_calc_rate_stats(struct minstrel_rate_stats *mrs);
int minstrel_get_tp_avg(struct minstrel_rate *mr);

/* debugfs */
int minstrel_stats_open(struct inode *inode, struct file *file);
Expand Down
12 changes: 6 additions & 6 deletions net/mac80211/rc80211_minstrel_debugfs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -75,7 +75,7 @@ minstrel_stats_open(struct inode *inode, struct file *file)
{
struct minstrel_sta_info *mi = inode->i_private;
struct minstrel_debugfs_info *ms;
unsigned int i, tp, prob, eprob;
unsigned int i, tp_avg, prob, eprob;
char *p;

ms = kmalloc(2048, GFP_KERNEL);
Expand Down Expand Up @@ -105,13 +105,13 @@ minstrel_stats_open(struct inode *inode, struct file *file)
p += sprintf(p, "%3u ", i);
p += sprintf(p, "%6u ", mr->perfect_tx_time);

tp = MINSTREL_TRUNC(mrs->cur_tp / 10);
tp_avg = minstrel_get_tp_avg(mr);
prob = MINSTREL_TRUNC(mrs->cur_prob * 1000);
eprob = MINSTREL_TRUNC(mrs->prob_ewma * 1000);

p += sprintf(p, " %4u.%1u %3u.%1u %3u.%1u %3u"
" %3u %-3u %9llu %-9llu\n",
tp / 10, tp % 10,
tp_avg / 10, tp_avg % 10,
eprob / 10, eprob % 10,
prob / 10, prob % 10,
mrs->retry_count,
Expand Down Expand Up @@ -144,7 +144,7 @@ minstrel_stats_csv_open(struct inode *inode, struct file *file)
{
struct minstrel_sta_info *mi = inode->i_private;
struct minstrel_debugfs_info *ms;
unsigned int i, tp, prob, eprob;
unsigned int i, tp_avg, prob, eprob;
char *p;

ms = kmalloc(2048, GFP_KERNEL);
Expand All @@ -169,13 +169,13 @@ minstrel_stats_csv_open(struct inode *inode, struct file *file)
p += sprintf(p, "%u,", i);
p += sprintf(p, "%u,",mr->perfect_tx_time);

tp = MINSTREL_TRUNC(mrs->cur_tp / 10);
tp_avg = minstrel_get_tp_avg(mr);
prob = MINSTREL_TRUNC(mrs->cur_prob * 1000);
eprob = MINSTREL_TRUNC(mrs->prob_ewma * 1000);

p += sprintf(p, "%u.%u,%u.%u,%u.%u,%u,%u,%u,"
"%llu,%llu,%d,%d\n",
tp / 10, tp % 10,
tp_avg / 10, tp_avg % 10,
eprob / 10, eprob % 10,
prob / 10, prob % 10,
mrs->retry_count,
Expand Down
77 changes: 46 additions & 31 deletions net/mac80211/rc80211_minstrel_ht.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -314,11 +314,11 @@ minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)
}

/*
* Calculate throughput based on the average A-MPDU length, taking into account
* the expected number of retransmissions and their expected length
* Return current throughput based on the average A-MPDU length, taking into
* account the expected number of retransmissions and their expected length
*/
static void
minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)
int
minstrel_ht_get_tp_avg(struct minstrel_ht_sta *mi, int group, int rate)
{
struct minstrel_rate_stats *mrs;
unsigned int nsecs = 0;
Expand All @@ -328,10 +328,8 @@ minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)
tmp_prob_ewma = mrs->prob_ewma;

/* do not account throughput if sucess prob is below 10% */
if (mrs->prob_ewma < MINSTREL_FRAC(10, 100)) {
mrs->cur_tp = 0;
return;
}
if (mrs->prob_ewma < MINSTREL_FRAC(10, 100))
return 0;

/*
* For the throughput calculation, limit the probability value to 90% to
Expand All @@ -346,7 +344,7 @@ minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)
nsecs += minstrel_mcs_groups[group].duration[rate];

/* prob is scaled - see MINSTREL_FRAC above */
mrs->cur_tp = MINSTREL_TRUNC(1000000 * ((tmp_prob_ewma * 1000) / nsecs));
return MINSTREL_TRUNC(100000 * ((tmp_prob_ewma * 1000) / nsecs));
}

/*
Expand All @@ -360,22 +358,22 @@ static void
minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u16 index,
u16 *tp_list)
{
int cur_group, cur_idx, cur_thr, cur_prob;
int tmp_group, tmp_idx, tmp_thr, tmp_prob;
int cur_group, cur_idx, cur_tp_avg, cur_prob;
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_thr = mi->groups[cur_group].rates[cur_idx].cur_tp;
cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx);
cur_prob = mi->groups[cur_group].rates[cur_idx].prob_ewma;

do {
tmp_group = tp_list[j - 1] / MCS_GROUP_RATES;
tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES;
tmp_thr = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx);
tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;
if (cur_thr < tmp_thr ||
(cur_thr == tmp_thr && cur_prob <= tmp_prob))
if (cur_tp_avg < tmp_tp_avg ||
(cur_tp_avg == tmp_tp_avg && cur_prob <= tmp_prob))
break;
j--;
} while (j > 0);
Expand All @@ -396,14 +394,19 @@ minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 index)
{
struct minstrel_mcs_group_data *mg;
struct minstrel_rate_stats *mrs;
int tmp_group, tmp_idx, tmp_tp, tmp_prob, max_tp_group;
int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
int max_tp_group, cur_tp_avg, cur_group, cur_idx;
int max_group_prob_rate_group, max_group_prob_rate_idx;
int max_group_prob_rate_tp_avg;

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];

tmp_group = mi->max_prob_rate / MCS_GROUP_RATES;
tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES;
tmp_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx);
tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_ewma;

/* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
Expand All @@ -414,9 +417,18 @@ minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 index)
return;

if (mrs->prob_ewma > MINSTREL_FRAC(75, 100)) {
if (mrs->cur_tp > tmp_tp)
cur_tp_avg = minstrel_ht_get_tp_avg(mi, cur_group, cur_idx);
if (cur_tp_avg > tmp_tp_avg)
mi->max_prob_rate = index;
if (mrs->cur_tp > mg->rates[mg->max_group_prob_rate].cur_tp)

max_group_prob_rate_group = mg->max_group_prob_rate /
MCS_GROUP_RATES;
max_group_prob_rate_idx = mg->max_group_prob_rate %
MCS_GROUP_RATES;
max_group_prob_rate_tp_avg = minstrel_ht_get_tp_avg(mi,
max_group_prob_rate_group,
max_group_prob_rate_idx);
if (cur_tp_avg > max_group_prob_rate_tp_avg)
mg->max_group_prob_rate = index;
} else {
if (mrs->prob_ewma > tmp_prob)
Expand All @@ -443,11 +455,11 @@ minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta *mi,

tmp_group = tmp_cck_tp_rate[0] / MCS_GROUP_RATES;
tmp_idx = tmp_cck_tp_rate[0] % MCS_GROUP_RATES;
tmp_cck_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
tmp_cck_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx);

tmp_group = tmp_mcs_tp_rate[0] / MCS_GROUP_RATES;
tmp_idx = tmp_mcs_tp_rate[0] % MCS_GROUP_RATES;
tmp_mcs_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
tmp_mcs_tp = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx);

if (tmp_cck_tp > tmp_mcs_tp) {
for(i = 0; i < MAX_THR_RATES; i++) {
Expand All @@ -466,8 +478,7 @@ static inline void
minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi)
{
struct minstrel_mcs_group_data *mg;
struct minstrel_rate_stats *mrs;
int tmp_max_streams, group;
int tmp_max_streams, group, tmp_idx;
int tmp_tp = 0;

tmp_max_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
Expand All @@ -476,11 +487,14 @@ minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi)
mg = &mi->groups[group];
if (!mg->supported || group == MINSTREL_CCK_GROUP)
continue;
mrs = minstrel_get_ratestats(mi, mg->max_group_prob_rate);
if (tmp_tp < mrs->cur_tp &&

tmp_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;

if (tmp_tp < minstrel_ht_get_tp_avg(mi, group, tmp_idx) &&
(minstrel_mcs_groups[group].streams < tmp_max_streams)) {
mi->max_prob_rate = mg->max_group_prob_rate;
tmp_tp = mrs->cur_tp;
tmp_tp = minstrel_ht_get_tp_avg(mi, group,
tmp_idx);
}
}
}
Expand Down Expand Up @@ -541,9 +555,8 @@ minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
mrs = &mg->rates[i];
mrs->retry_updated = false;
minstrel_calc_rate_stats(mrs);
minstrel_ht_calc_tp(mi, group, i);

if (!mrs->cur_tp)
if (minstrel_ht_get_tp_avg(mi, group, i) == 0)
continue;

/* Find max throughput rate set */
Expand Down Expand Up @@ -1302,16 +1315,18 @@ static u32 minstrel_ht_get_expected_throughput(void *priv_sta)
{
struct minstrel_ht_sta_priv *msp = priv_sta;
struct minstrel_ht_sta *mi = &msp->ht;
int i, j;
int i, j, tp_avg;

if (!msp->is_ht)
return mac80211_minstrel.get_expected_throughput(priv_sta);

i = mi->max_tp_rate[0] / MCS_GROUP_RATES;
j = mi->max_tp_rate[0] % MCS_GROUP_RATES;

/* convert cur_tp from pkt per second in kbps */
return mi->groups[i].rates[j].cur_tp * AVG_PKT_SIZE * 8 / 1024;
/* convert tp_avg from pkt per second in kbps */
tp_avg = minstrel_ht_get_tp_avg(mi, i, j) * AVG_PKT_SIZE * 8 / 1024;

return tp_avg;
}

static const struct rate_control_ops mac80211_minstrel_ht = {
Expand Down
1 change: 1 addition & 0 deletions net/mac80211/rc80211_minstrel_ht.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -121,5 +121,6 @@ struct minstrel_ht_sta_priv {

void minstrel_ht_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir);
void minstrel_ht_remove_sta_debugfs(void *priv, void *priv_sta);
int minstrel_ht_get_tp_avg(struct minstrel_ht_sta *mi, int group, int rate);

#endif
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