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Commit 6a27b2c4 authored by Thomas Huehn's avatar Thomas Huehn Committed by Johannes Berg
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mac80211: restructure per-rate throughput calculation into function



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: default avatarThomas Huehn <thomas@net.t-labs.tu-berlin.de>
Acked-by: default avatarFelix Fietkau <nbd@openwrt.org>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 9134073b
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+28 −15
Original line number Diff line number Diff line
@@ -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)
@@ -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;
@@ -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) ||
@@ -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)
@@ -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 = {
+1 −3
Original line number Diff line number Diff line
@@ -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 */
@@ -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);
+6 −6
Original line number Diff line number Diff line
@@ -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);
@@ -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,
@@ -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);
@@ -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,
+46 −31
Original line number Diff line number Diff line
@@ -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;
@@ -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
@@ -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));
}

/*
@@ -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);
@@ -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
@@ -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)
@@ -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++) {
@@ -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] /
@@ -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);
		}
	}
}
@@ -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 */
@@ -1302,7 +1315,7 @@ 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);
@@ -1310,8 +1323,10 @@ static u32 minstrel_ht_get_expected_throughput(void *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 = {
+1 −0
Original line number Diff line number Diff line
@@ -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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