From 4f0bc9c61bae9c74ffcf5dbdbd241cbf0ec3a44e Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Wed, 14 Dec 2016 20:47:00 +0100 Subject: [PATCH] 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 Signed-off-by: Felix Fietkau Signed-off-by: Johannes Berg --- net/mac80211/rc80211_minstrel.c | 8 +++---- net/mac80211/rc80211_minstrel.h | 25 ++++++++++++---------- net/mac80211/rc80211_minstrel_debugfs.c | 8 +++++-- net/mac80211/rc80211_minstrel_ht_debugfs.c | 8 +++++-- 4 files changed, 30 insertions(+), 19 deletions(-) diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c index a284ea08f048..11a4cc393a98 100644 --- a/net/mac80211/rc80211_minstrel.c +++ b/net/mac80211/rc80211_minstrel.c @@ -168,10 +168,10 @@ 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, - cur_prob, - mrs->prob_ewma, - EWMA_LEVEL); + mrs->prob_ewmv = minstrel_ewmv(mrs->prob_ewmv, + cur_prob, + mrs->prob_ewma, + EWMA_LEVEL); /*update exponential weighted moving avarage */ mrs->prob_ewma = minstrel_ewma(mrs->prob_ewma, diff --git a/net/mac80211/rc80211_minstrel.h b/net/mac80211/rc80211_minstrel.h index 03716fddaf24..ea86e6784154 100644 --- a/net/mac80211/rc80211_minstrel.h +++ b/net/mac80211/rc80211_minstrel.h @@ -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); diff --git a/net/mac80211/rc80211_minstrel_debugfs.c b/net/mac80211/rc80211_minstrel_debugfs.c index ca0bafd6a44e..36fc971deb86 100644 --- a/net/mac80211/rc80211_minstrel_debugfs.c +++ b/net/mac80211/rc80211_minstrel_debugfs.c @@ -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, diff --git a/net/mac80211/rc80211_minstrel_ht_debugfs.c b/net/mac80211/rc80211_minstrel_ht_debugfs.c index 0cecd23bb834..7d969e300fb3 100644 --- a/net/mac80211/rc80211_minstrel_ht_debugfs.c +++ b/net/mac80211/rc80211_minstrel_ht_debugfs.c @@ -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,