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![Thomas Huehn](/assets/img/avatar_default.png)
This patch adds the statistical descriptor "standard deviation" to better describe the current properties of Minstrel and Minstrel-HTs success probability distribution. The standard deviation (SD) is calculated as exponential weighted moving standard deviation (EWMSD) and its current value is added as new column in all rc_stats (in debugfs). Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de> Acked-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
170 lines
4.2 KiB
C
170 lines
4.2 KiB
C
/*
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* Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef __RC_MINSTREL_H
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#define __RC_MINSTREL_H
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#define EWMA_LEVEL 96 /* ewma weighting factor [/EWMA_DIV] */
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#define EWMA_DIV 128
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#define SAMPLE_COLUMNS 10 /* number of columns in sample table */
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/* scaled fraction values */
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#define MINSTREL_SCALE 16
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#define MINSTREL_FRAC(val, div) (((val) << MINSTREL_SCALE) / div)
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#define MINSTREL_TRUNC(val) ((val) >> MINSTREL_SCALE)
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/* number of highest throughput rates to consider*/
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#define MAX_THR_RATES 4
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/*
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* Perform EWMA (Exponentially Weighted Moving Average) calculation
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*/
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static inline int
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minstrel_ewma(int old, int new, int weight)
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{
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int diff, incr;
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diff = new - old;
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incr = (EWMA_DIV - weight) * diff / EWMA_DIV;
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return old + incr;
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}
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/*
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* Perform EWMSD (Exponentially Weighted Moving Standard Deviation) 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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{
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int diff, incr, tmp_var;
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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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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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}
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struct minstrel_rate_stats {
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/* current / last sampling period attempts/success counters */
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u16 attempts, last_attempts;
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u16 success, last_success;
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/* total attempts/success counters */
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u64 att_hist, succ_hist;
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/* statistis of packet delivery probability
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* cur_prob - current prob within last update intervall
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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 cur_prob;
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unsigned int prob_ewma;
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u16 prob_ewmsd;
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/* maximum retry counts */
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u8 retry_count;
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u8 retry_count_rtscts;
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u8 sample_skipped;
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bool retry_updated;
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};
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struct minstrel_rate {
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int bitrate;
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s8 rix;
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u8 retry_count_cts;
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u8 adjusted_retry_count;
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unsigned int perfect_tx_time;
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unsigned int ack_time;
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int sample_limit;
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struct minstrel_rate_stats stats;
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};
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struct minstrel_sta_info {
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struct ieee80211_sta *sta;
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unsigned long last_stats_update;
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unsigned int sp_ack_dur;
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unsigned int rate_avg;
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unsigned int lowest_rix;
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u8 max_tp_rate[MAX_THR_RATES];
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u8 max_prob_rate;
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unsigned int total_packets;
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unsigned int sample_packets;
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int sample_deferred;
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unsigned int sample_row;
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unsigned int sample_column;
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int n_rates;
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struct minstrel_rate *r;
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bool prev_sample;
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/* sampling table */
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u8 *sample_table;
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#ifdef CONFIG_MAC80211_DEBUGFS
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struct dentry *dbg_stats;
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struct dentry *dbg_stats_csv;
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#endif
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};
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struct minstrel_priv {
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struct ieee80211_hw *hw;
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bool has_mrr;
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unsigned int cw_min;
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unsigned int cw_max;
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unsigned int max_retry;
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unsigned int segment_size;
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unsigned int update_interval;
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unsigned int lookaround_rate;
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unsigned int lookaround_rate_mrr;
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u8 cck_rates[4];
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#ifdef CONFIG_MAC80211_DEBUGFS
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/*
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* enable fixed rate processing per RC
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* - write static index to debugfs:ieee80211/phyX/rc/fixed_rate_idx
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* - write -1 to enable RC processing again
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* - setting will be applied on next update
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*/
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u32 fixed_rate_idx;
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struct dentry *dbg_fixed_rate;
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#endif
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};
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struct minstrel_debugfs_info {
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size_t len;
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char buf[];
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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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/* Recalculate success probabilities and counters for a given rate using EWMA */
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void minstrel_calc_rate_stats(struct minstrel_rate_stats *mrs);
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int minstrel_get_tp_avg(struct minstrel_rate *mr, int prob_ewma);
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/* debugfs */
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int minstrel_stats_open(struct inode *inode, struct file *file);
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int minstrel_stats_csv_open(struct inode *inode, struct file *file);
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ssize_t minstrel_stats_read(struct file *file, char __user *buf, size_t len, loff_t *ppos);
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int minstrel_stats_release(struct inode *inode, struct file *file);
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#endif
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