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: Thomas Huehn <thomas.huehn@evernet-eg.de> Signed-off-by: Felix Fietkau <nbd@nbd.name> Signed-off-by: Johannes Berg <johannes.berg@intel.com>zero-colors
Felix Fietkau
Johannes Berg
parent
0217eefa64
commit
4f0bc9c61b
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@ -168,10 +168,10 @@ minstrel_calc_rate_stats(struct minstrel_rate_stats *mrs)
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mrs->prob_ewma = cur_prob;
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} else {
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/* update exponential weighted moving variance */
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mrs->prob_ewmsd = minstrel_ewmsd(mrs->prob_ewmsd,
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cur_prob,
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mrs->prob_ewma,
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EWMA_LEVEL);
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mrs->prob_ewmv = minstrel_ewmv(mrs->prob_ewmv,
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cur_prob,
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mrs->prob_ewma,
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EWMA_LEVEL);
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/*update exponential weighted moving avarage */
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mrs->prob_ewma = minstrel_ewma(mrs->prob_ewma,
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@ -36,21 +36,16 @@ minstrel_ewma(int old, int new, int weight)
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}
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/*
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* Perform EWMSD (Exponentially Weighted Moving Standard Deviation) calculation
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* Perform EWMV (Exponentially Weighted Moving Variance) calculation
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*/
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static inline int
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minstrel_ewmsd(int old_ewmsd, int cur_prob, int prob_ewma, int weight)
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minstrel_ewmv(int old_ewmv, int cur_prob, int prob_ewma, int weight)
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{
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int diff, incr, tmp_var;
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int diff, incr;
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/* calculate exponential weighted moving variance */
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diff = MINSTREL_TRUNC((cur_prob - prob_ewma) * 1000000);
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diff = cur_prob - prob_ewma;
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incr = (EWMA_DIV - weight) * diff / EWMA_DIV;
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tmp_var = old_ewmsd * old_ewmsd;
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tmp_var = weight * (tmp_var + diff * incr / 1000000) / EWMA_DIV;
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/* return standard deviation */
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return (u16) int_sqrt(tmp_var);
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return weight * (old_ewmv + MINSTREL_TRUNC(diff * incr)) / EWMA_DIV;
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}
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struct minstrel_rate_stats {
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@ -65,7 +60,7 @@ struct minstrel_rate_stats {
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* prob_ewma - exponential weighted moving average of prob
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* prob_ewmsd - exp. weighted moving standard deviation of prob */
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unsigned int prob_ewma;
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u16 prob_ewmsd;
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u16 prob_ewmv;
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/* maximum retry counts */
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u8 retry_count;
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@ -151,6 +146,14 @@ struct minstrel_debugfs_info {
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char buf[];
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};
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/* Get EWMSD (Exponentially Weighted Moving Standard Deviation) * 10 */
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static inline int
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minstrel_get_ewmsd10(struct minstrel_rate_stats *mrs)
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{
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unsigned int ewmv = mrs->prob_ewmv;
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return int_sqrt(MINSTREL_TRUNC(ewmv * 1000 * 1000));
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}
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extern const struct rate_control_ops mac80211_minstrel;
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void minstrel_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir);
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void minstrel_remove_sta_debugfs(void *priv, void *priv_sta);
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@ -93,6 +93,7 @@ minstrel_stats_open(struct inode *inode, struct file *file)
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for (i = 0; i < mi->n_rates; i++) {
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struct minstrel_rate *mr = &mi->r[i];
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struct minstrel_rate_stats *mrs = &mi->r[i].stats;
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unsigned int prob_ewmsd;
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*(p++) = (i == mi->max_tp_rate[0]) ? 'A' : ' ';
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*(p++) = (i == mi->max_tp_rate[1]) ? 'B' : ' ';
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@ -108,6 +109,7 @@ minstrel_stats_open(struct inode *inode, struct file *file)
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tp_max = minstrel_get_tp_avg(mr, MINSTREL_FRAC(100,100));
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tp_avg = minstrel_get_tp_avg(mr, mrs->prob_ewma);
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eprob = MINSTREL_TRUNC(mrs->prob_ewma * 1000);
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prob_ewmsd = minstrel_get_ewmsd10(mrs);
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p += sprintf(p, "%4u.%1u %4u.%1u %3u.%1u %3u.%1u"
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" %3u %3u %-3u "
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@ -115,7 +117,7 @@ minstrel_stats_open(struct inode *inode, struct file *file)
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tp_max / 10, tp_max % 10,
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tp_avg / 10, tp_avg % 10,
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eprob / 10, eprob % 10,
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mrs->prob_ewmsd / 10, mrs->prob_ewmsd % 10,
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prob_ewmsd / 10, prob_ewmsd % 10,
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mrs->retry_count,
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mrs->last_success,
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mrs->last_attempts,
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@ -159,6 +161,7 @@ minstrel_stats_csv_open(struct inode *inode, struct file *file)
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for (i = 0; i < mi->n_rates; i++) {
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struct minstrel_rate *mr = &mi->r[i];
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struct minstrel_rate_stats *mrs = &mi->r[i].stats;
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unsigned int prob_ewmsd;
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p += sprintf(p, "%s" ,((i == mi->max_tp_rate[0]) ? "A" : ""));
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p += sprintf(p, "%s" ,((i == mi->max_tp_rate[1]) ? "B" : ""));
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@ -174,13 +177,14 @@ minstrel_stats_csv_open(struct inode *inode, struct file *file)
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tp_max = minstrel_get_tp_avg(mr, MINSTREL_FRAC(100,100));
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tp_avg = minstrel_get_tp_avg(mr, mrs->prob_ewma);
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eprob = MINSTREL_TRUNC(mrs->prob_ewma * 1000);
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prob_ewmsd = minstrel_get_ewmsd10(mrs);
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p += sprintf(p, "%u.%u,%u.%u,%u.%u,%u.%u,%u,%u,%u,"
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"%llu,%llu,%d,%d\n",
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tp_max / 10, tp_max % 10,
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tp_avg / 10, tp_avg % 10,
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eprob / 10, eprob % 10,
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mrs->prob_ewmsd / 10, mrs->prob_ewmsd % 10,
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prob_ewmsd / 10, prob_ewmsd % 10,
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mrs->retry_count,
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mrs->last_success,
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mrs->last_attempts,
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@ -41,6 +41,7 @@ minstrel_ht_stats_dump(struct minstrel_ht_sta *mi, int i, char *p)
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struct minstrel_rate_stats *mrs = &mi->groups[i].rates[j];
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static const int bitrates[4] = { 10, 20, 55, 110 };
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int idx = i * MCS_GROUP_RATES + j;
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unsigned int prob_ewmsd;
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if (!(mi->supported[i] & BIT(j)))
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continue;
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@ -84,6 +85,7 @@ minstrel_ht_stats_dump(struct minstrel_ht_sta *mi, int i, char *p)
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tp_max = minstrel_ht_get_tp_avg(mi, i, j, MINSTREL_FRAC(100, 100));
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tp_avg = minstrel_ht_get_tp_avg(mi, i, j, mrs->prob_ewma);
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eprob = MINSTREL_TRUNC(mrs->prob_ewma * 1000);
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prob_ewmsd = minstrel_get_ewmsd10(mrs);
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p += sprintf(p, "%4u.%1u %4u.%1u %3u.%1u %3u.%1u"
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" %3u %3u %-3u "
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@ -91,7 +93,7 @@ minstrel_ht_stats_dump(struct minstrel_ht_sta *mi, int i, char *p)
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tp_max / 10, tp_max % 10,
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tp_avg / 10, tp_avg % 10,
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eprob / 10, eprob % 10,
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mrs->prob_ewmsd / 10, mrs->prob_ewmsd % 10,
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prob_ewmsd / 10, prob_ewmsd % 10,
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mrs->retry_count,
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mrs->last_success,
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mrs->last_attempts,
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@ -185,6 +187,7 @@ minstrel_ht_stats_csv_dump(struct minstrel_ht_sta *mi, int i, char *p)
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struct minstrel_rate_stats *mrs = &mi->groups[i].rates[j];
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static const int bitrates[4] = { 10, 20, 55, 110 };
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int idx = i * MCS_GROUP_RATES + j;
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unsigned int prob_ewmsd;
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if (!(mi->supported[i] & BIT(j)))
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continue;
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@ -225,13 +228,14 @@ minstrel_ht_stats_csv_dump(struct minstrel_ht_sta *mi, int i, char *p)
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tp_max = minstrel_ht_get_tp_avg(mi, i, j, MINSTREL_FRAC(100, 100));
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tp_avg = minstrel_ht_get_tp_avg(mi, i, j, mrs->prob_ewma);
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eprob = MINSTREL_TRUNC(mrs->prob_ewma * 1000);
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prob_ewmsd = minstrel_get_ewmsd10(mrs);
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p += sprintf(p, "%u.%u,%u.%u,%u.%u,%u.%u,%u,%u,"
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"%u,%llu,%llu,",
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tp_max / 10, tp_max % 10,
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tp_avg / 10, tp_avg % 10,
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eprob / 10, eprob % 10,
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mrs->prob_ewmsd / 10, mrs->prob_ewmsd % 10,
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prob_ewmsd / 10, prob_ewmsd % 10,
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mrs->retry_count,
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mrs->last_success,
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mrs->last_attempts,
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