From: Felix Fietkau <nbd@nbd.name>
To: linux-wireless@vger.kernel.org
Cc: johannes@sipsolutions.net
Subject: [PATCH 9/9] mac80211: rc80211_minstrel: remove variance / stddev calculation
Date: Sat, 6 Oct 2018 19:35:07 +0200 [thread overview]
Message-ID: <20181006173507.7316-9-nbd@nbd.name> (raw)
In-Reply-To: <20181006173507.7316-1-nbd@nbd.name>
When there are few packets (e.g. for sampling attempts), the exponentially
weighted variance is usually vastly overestimated, making the resulting data
essentially useless. As far as I know, there has not been any practical use
for this, so let's not waste any cycles on it.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
net/mac80211/rc80211_minstrel.c | 6 -----
net/mac80211/rc80211_minstrel.h | 26 +---------------------
net/mac80211/rc80211_minstrel_debugfs.c | 14 ++++--------
net/mac80211/rc80211_minstrel_ht_debugfs.c | 14 ++++--------
4 files changed, 9 insertions(+), 51 deletions(-)
diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c
index dead57ba9eac..a34e9c2ca626 100644
--- a/net/mac80211/rc80211_minstrel.c
+++ b/net/mac80211/rc80211_minstrel.c
@@ -167,12 +167,6 @@ minstrel_calc_rate_stats(struct minstrel_rate_stats *mrs)
if (unlikely(!mrs->att_hist)) {
mrs->prob_ewma = cur_prob;
} else {
- /* update exponential weighted moving variance */
- 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,
cur_prob,
diff --git a/net/mac80211/rc80211_minstrel.h b/net/mac80211/rc80211_minstrel.h
index 54b2b2c3e10a..23ec953e3a24 100644
--- a/net/mac80211/rc80211_minstrel.h
+++ b/net/mac80211/rc80211_minstrel.h
@@ -35,19 +35,6 @@ minstrel_ewma(int old, int new, int weight)
return old + incr;
}
-/*
- * Perform EWMV (Exponentially Weighted Moving Variance) calculation
- */
-static inline int
-minstrel_ewmv(int old_ewmv, int cur_prob, int prob_ewma, int weight)
-{
- int diff, incr;
-
- diff = cur_prob - prob_ewma;
- incr = (EWMA_DIV - weight) * diff / EWMA_DIV;
- return weight * (old_ewmv + MINSTREL_TRUNC(diff * incr)) / EWMA_DIV;
-}
-
struct minstrel_rate_stats {
/* current / last sampling period attempts/success counters */
u16 attempts, last_attempts;
@@ -56,11 +43,8 @@ struct minstrel_rate_stats {
/* total attempts/success counters */
u32 att_hist, succ_hist;
- /* statistis of packet delivery probability
- * prob_ewma - exponential weighted moving average of prob
- * prob_ewmsd - exp. weighted moving standard deviation of prob */
+ /* prob_ewma - exponential weighted moving average of prob */
u16 prob_ewma;
- u16 prob_ewmv;
/* maximum retry counts */
u8 retry_count;
@@ -140,14 +124,6 @@ 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);
diff --git a/net/mac80211/rc80211_minstrel_debugfs.c b/net/mac80211/rc80211_minstrel_debugfs.c
index 698a668b5316..c8afd85b51a0 100644
--- a/net/mac80211/rc80211_minstrel_debugfs.c
+++ b/net/mac80211/rc80211_minstrel_debugfs.c
@@ -70,14 +70,13 @@ minstrel_stats_open(struct inode *inode, struct file *file)
p = ms->buf;
p += sprintf(p, "\n");
p += sprintf(p,
- "best __________rate_________ ________statistics________ ____last_____ ______sum-of________\n");
+ "best __________rate_________ ____statistics___ ____last_____ ______sum-of________\n");
p += sprintf(p,
- "rate [name idx airtime max_tp] [avg(tp) avg(prob) sd(prob)] [retry|suc|att] [#success | #attempts]\n");
+ "rate [name idx airtime max_tp] [avg(tp) avg(prob)] [retry|suc|att] [#success | #attempts]\n");
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' : ' ';
@@ -93,15 +92,13 @@ 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"
+ p += sprintf(p, "%4u.%1u %4u.%1u %3u.%1u"
" %3u %3u %-3u "
"%9llu %-9llu\n",
tp_max / 10, tp_max % 10,
tp_avg / 10, tp_avg % 10,
eprob / 10, eprob % 10,
- prob_ewmsd / 10, prob_ewmsd % 10,
mrs->retry_count,
mrs->last_success,
mrs->last_attempts,
@@ -137,7 +134,6 @@ 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" : ""));
@@ -153,14 +149,12 @@ 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,"
+ p += sprintf(p, "%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,
- 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 8065da2cf0f1..57820a5f2c16 100644
--- a/net/mac80211/rc80211_minstrel_ht_debugfs.c
+++ b/net/mac80211/rc80211_minstrel_ht_debugfs.c
@@ -57,7 +57,6 @@ 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;
unsigned int duration;
if (!(mi->supported[i] & BIT(j)))
@@ -104,15 +103,13 @@ 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"
+ p += sprintf(p, "%4u.%1u %4u.%1u %3u.%1u"
" %3u %3u %-3u "
"%9llu %-9llu\n",
tp_max / 10, tp_max % 10,
tp_avg / 10, tp_avg % 10,
eprob / 10, eprob % 10,
- prob_ewmsd / 10, prob_ewmsd % 10,
mrs->retry_count,
mrs->last_success,
mrs->last_attempts,
@@ -149,9 +146,9 @@ minstrel_ht_stats_open(struct inode *inode, struct file *file)
p += sprintf(p, "\n");
p += sprintf(p,
- " best ____________rate__________ ________statistics________ _____last____ ______sum-of________\n");
+ " best ____________rate__________ ____statistics___ _____last____ ______sum-of________\n");
p += sprintf(p,
- "mode guard # rate [name idx airtime max_tp] [avg(tp) avg(prob) sd(prob)] [retry|suc|att] [#success | #attempts]\n");
+ "mode guard # rate [name idx airtime max_tp] [avg(tp) avg(prob)] [retry|suc|att] [#success | #attempts]\n");
p = minstrel_ht_stats_dump(mi, MINSTREL_CCK_GROUP, p);
for (i = 0; i < MINSTREL_CCK_GROUP; i++)
@@ -206,7 +203,6 @@ 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;
unsigned int duration;
if (!(mi->supported[i] & BIT(j)))
@@ -251,14 +247,12 @@ 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,"
+ p += sprintf(p, "%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,
- prob_ewmsd / 10, prob_ewmsd % 10,
mrs->retry_count,
mrs->last_success,
mrs->last_attempts,
--
2.17.0
next prev parent reply other threads:[~2018-10-06 17:35 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-06 17:34 [PATCH 1/9] mac80211: minstrel: Enable STBC and LDPC for VHT Rates Felix Fietkau
2018-10-06 17:35 ` [PATCH 2/9] mac80211: minstrel: remove unnecessary debugfs cleanup code Felix Fietkau
2018-10-06 17:35 ` [PATCH 3/9] mac80211: minstrel: merge with minstrel_ht, always enable VHT support Felix Fietkau
2018-10-06 17:35 ` [PATCH 4/9] mac80211: minstrel: reduce minstrel_mcs_groups size Felix Fietkau
2018-10-06 17:35 ` [PATCH 5/9] mac80211: minstrel: fix using short preamble CCK rates on HT clients Felix Fietkau
2018-10-06 17:35 ` [PATCH 6/9] mac80211: minstrel: fix CCK rate group streams value Felix Fietkau
2018-10-06 17:35 ` [PATCH 7/9] mac80211: minstrel: fix sampling/reporting of CCK rates in HT mode Felix Fietkau
2018-10-06 17:35 ` [PATCH 8/9] mac80211: minstrel: do not sample rates 3 times slower than max_prob_rate Felix Fietkau
2018-10-06 17:35 ` Felix Fietkau [this message]
2018-10-06 17:59 ` [PATCH 9/9] mac80211: rc80211_minstrel: remove variance / stddev calculation Dave Taht
2018-10-06 18:18 ` Felix Fietkau
2018-10-06 18:23 ` Dave Taht
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