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Commit 4f0bc9c6 authored by Felix Fietkau's avatar Felix Fietkau Committed by Johannes Berg
Browse files

mac80211: minstrel: store probability variance instead of standard deviation 



This avoids the costly int_sqrt calls in the statistics update and moves
it to the debugfs code instead.
This also fixes an overflow in the previous standard deviation
calculation.

Signed-off-by: default avatarThomas Huehn <thomas.huehn@evernet-eg.de>
Signed-off-by: default avatarFelix Fietkau <nbd@nbd.name>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 0217eefa

net/mac80211/rc80211_minstrel.c

+4 −4
Original line number Diff line number Diff line
@@ -168,7 +168,7 @@ minstrel_calc_rate_stats(struct minstrel_rate_stats *mrs) 
			mrs->prob_ewma = cur_prob;

		} else {

			/* update exponential weighted moving variance */

			mrs->prob_ewmsd = minstrel_ewmsd(mrs->prob_ewmsd,

			mrs->prob_ewmv = minstrel_ewmv(mrs->prob_ewmv,

							cur_prob,

							mrs->prob_ewma,

							EWMA_LEVEL);

net/mac80211/rc80211_minstrel.h

+14 −11
Original line number Diff line number Diff line
@@ -36,21 +36,16 @@ minstrel_ewma(int old, int new, int weight) 
}



/*

 * Perform EWMSD (Exponentially Weighted Moving Standard Deviation) calculation

 * Perform EWMV (Exponentially Weighted Moving Variance) calculation

 */

static inline int

minstrel_ewmsd(int old_ewmsd, int cur_prob, int prob_ewma, int weight)

minstrel_ewmv(int old_ewmv, int cur_prob, int prob_ewma, int weight)

{

	int diff, incr, tmp_var;

	int diff, incr;



	/* calculate exponential weighted moving variance */

	diff = MINSTREL_TRUNC((cur_prob - prob_ewma) * 1000000);

	diff = cur_prob - prob_ewma;

	incr = (EWMA_DIV - weight) * diff / EWMA_DIV;

	tmp_var = old_ewmsd * old_ewmsd;

	tmp_var = weight * (tmp_var + diff * incr / 1000000) / EWMA_DIV;



	/* return standard deviation */

	return (u16) int_sqrt(tmp_var);

	return weight * (old_ewmv + MINSTREL_TRUNC(diff * incr)) / EWMA_DIV;

}



struct minstrel_rate_stats {
@@ -65,7 +60,7 @@ struct minstrel_rate_stats { 
	 *  prob_ewma - exponential weighted moving average of prob

	 *  prob_ewmsd - exp. weighted moving standard deviation of prob */

	unsigned int prob_ewma;

	u16 prob_ewmsd;

	u16 prob_ewmv;



	/* maximum retry counts */

	u8 retry_count;
@@ -151,6 +146,14 @@ struct minstrel_debugfs_info { 
	char buf[];

};



/* Get EWMSD (Exponentially Weighted Moving Standard Deviation) * 10 */

static inline int

minstrel_get_ewmsd10(struct minstrel_rate_stats *mrs)

{

	unsigned int ewmv = mrs->prob_ewmv;

	return int_sqrt(MINSTREL_TRUNC(ewmv * 1000 * 1000));

}



extern const struct rate_control_ops mac80211_minstrel;

void minstrel_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir);

void minstrel_remove_sta_debugfs(void *priv, void *priv_sta);

net/mac80211/rc80211_minstrel_debugfs.c

+6 −2
Original line number Diff line number Diff line
@@ -93,6 +93,7 @@ minstrel_stats_open(struct inode *inode, struct file *file) 
	for (i = 0; i < mi->n_rates; i++) {

		struct minstrel_rate *mr = &mi->r[i];

		struct minstrel_rate_stats *mrs = &mi->r[i].stats;

		unsigned int prob_ewmsd;



		*(p++) = (i == mi->max_tp_rate[0]) ? 'A' : ' ';

		*(p++) = (i == mi->max_tp_rate[1]) ? 'B' : ' ';
@@ -108,6 +109,7 @@ minstrel_stats_open(struct inode *inode, struct file *file) 
		tp_max = minstrel_get_tp_avg(mr, MINSTREL_FRAC(100,100));

		tp_avg = minstrel_get_tp_avg(mr, mrs->prob_ewma);

		eprob = MINSTREL_TRUNC(mrs->prob_ewma * 1000);

		prob_ewmsd = minstrel_get_ewmsd10(mrs);



		p += sprintf(p, "%4u.%1u    %4u.%1u     %3u.%1u    %3u.%1u"

				"     %3u   %3u %-3u   "
@@ -115,7 +117,7 @@ minstrel_stats_open(struct inode *inode, struct file *file) 
				tp_max / 10, tp_max % 10,

				tp_avg / 10, tp_avg % 10,

				eprob / 10, eprob % 10,

				mrs->prob_ewmsd / 10, mrs->prob_ewmsd % 10,

				prob_ewmsd / 10, prob_ewmsd % 10,

				mrs->retry_count,

				mrs->last_success,

				mrs->last_attempts,
@@ -159,6 +161,7 @@ minstrel_stats_csv_open(struct inode *inode, struct file *file) 
	for (i = 0; i < mi->n_rates; i++) {

		struct minstrel_rate *mr = &mi->r[i];

		struct minstrel_rate_stats *mrs = &mi->r[i].stats;

		unsigned int prob_ewmsd;



		p += sprintf(p, "%s" ,((i == mi->max_tp_rate[0]) ? "A" : ""));

		p += sprintf(p, "%s" ,((i == mi->max_tp_rate[1]) ? "B" : ""));
@@ -174,13 +177,14 @@ minstrel_stats_csv_open(struct inode *inode, struct file *file) 
		tp_max = minstrel_get_tp_avg(mr, MINSTREL_FRAC(100,100));

		tp_avg = minstrel_get_tp_avg(mr, mrs->prob_ewma);

		eprob = MINSTREL_TRUNC(mrs->prob_ewma * 1000);

		prob_ewmsd = minstrel_get_ewmsd10(mrs);



		p += sprintf(p, "%u.%u,%u.%u,%u.%u,%u.%u,%u,%u,%u,"

				"%llu,%llu,%d,%d\n",

				tp_max / 10, tp_max % 10,

				tp_avg / 10, tp_avg % 10,

				eprob / 10, eprob % 10,

				mrs->prob_ewmsd / 10, mrs->prob_ewmsd % 10,

				prob_ewmsd / 10, prob_ewmsd % 10,

				mrs->retry_count,

				mrs->last_success,

				mrs->last_attempts,

net/mac80211/rc80211_minstrel_ht_debugfs.c

+6 −2
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ minstrel_ht_stats_dump(struct minstrel_ht_sta *mi, int i, char *p) 
		struct minstrel_rate_stats *mrs = &mi->groups[i].rates[j];

		static const int bitrates[4] = { 10, 20, 55, 110 };

		int idx = i * MCS_GROUP_RATES + j;

		unsigned int prob_ewmsd;



		if (!(mi->supported[i] & BIT(j)))

			continue;
@@ -84,6 +85,7 @@ minstrel_ht_stats_dump(struct minstrel_ht_sta *mi, int i, char *p) 
		tp_max = minstrel_ht_get_tp_avg(mi, i, j, MINSTREL_FRAC(100, 100));

		tp_avg = minstrel_ht_get_tp_avg(mi, i, j, mrs->prob_ewma);

		eprob = MINSTREL_TRUNC(mrs->prob_ewma * 1000);

		prob_ewmsd = minstrel_get_ewmsd10(mrs);



		p += sprintf(p, "%4u.%1u    %4u.%1u     %3u.%1u    %3u.%1u"

				"     %3u   %3u %-3u   "
@@ -91,7 +93,7 @@ minstrel_ht_stats_dump(struct minstrel_ht_sta *mi, int i, char *p) 
				tp_max / 10, tp_max % 10,

				tp_avg / 10, tp_avg % 10,

				eprob / 10, eprob % 10,

				mrs->prob_ewmsd / 10, mrs->prob_ewmsd % 10,

				prob_ewmsd / 10, prob_ewmsd % 10,

				mrs->retry_count,

				mrs->last_success,

				mrs->last_attempts,
@@ -185,6 +187,7 @@ minstrel_ht_stats_csv_dump(struct minstrel_ht_sta *mi, int i, char *p) 
		struct minstrel_rate_stats *mrs = &mi->groups[i].rates[j];

		static const int bitrates[4] = { 10, 20, 55, 110 };

		int idx = i * MCS_GROUP_RATES + j;

		unsigned int prob_ewmsd;



		if (!(mi->supported[i] & BIT(j)))

			continue;
@@ -225,13 +228,14 @@ minstrel_ht_stats_csv_dump(struct minstrel_ht_sta *mi, int i, char *p) 
		tp_max = minstrel_ht_get_tp_avg(mi, i, j, MINSTREL_FRAC(100, 100));

		tp_avg = minstrel_ht_get_tp_avg(mi, i, j, mrs->prob_ewma);

		eprob = MINSTREL_TRUNC(mrs->prob_ewma * 1000);

		prob_ewmsd = minstrel_get_ewmsd10(mrs);



		p += sprintf(p, "%u.%u,%u.%u,%u.%u,%u.%u,%u,%u,"

				"%u,%llu,%llu,",

				tp_max / 10, tp_max % 10,

				tp_avg / 10, tp_avg % 10,

				eprob / 10, eprob % 10,

				mrs->prob_ewmsd / 10, mrs->prob_ewmsd % 10,

				prob_ewmsd / 10, prob_ewmsd % 10,

				mrs->retry_count,

				mrs->last_success,

				mrs->last_attempts,