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4fe40b8e15
Deferring sampling attempts to the second stage has some bad interactions
with drivers that process the rate table in hardware and use the probe flag
to indicate probing packets (e.g. most mt76 drivers). On affected drivers
it can lead to probing not working at all.
If the link conditions turn worse, it might not be such a good idea to
do a lot of sampling for lower rates in this case.
Fix this by simply skipping the sample attempt instead of deferring it,
but keep the checks that would allow it to be sampled if it was skipped
too often, but only if it has less than 95% success probability.
Also ensure that IEEE80211_TX_CTL_RATE_CTRL_PROBE is set for all probing
packets.
Cc: stable@vger.kernel.org
Fixes: cccf129f82 ("mac80211: add the 'minstrel' rate control algorithm")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20201111183359.43528-2-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
185 lines
3.9 KiB
C
185 lines
3.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
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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 12
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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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* Coefficients for moving average with noise filter (period=16),
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* scaled by 10 bits
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*
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* a1 = exp(-pi * sqrt(2) / period)
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* coeff2 = 2 * a1 * cos(sqrt(2) * 2 * pi / period)
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* coeff3 = -sqr(a1)
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* coeff1 = 1 - coeff2 - coeff3
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*/
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#define MINSTREL_AVG_COEFF1 (MINSTREL_FRAC(1, 1) - \
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MINSTREL_AVG_COEFF2 - \
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MINSTREL_AVG_COEFF3)
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#define MINSTREL_AVG_COEFF2 0x00001499
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#define MINSTREL_AVG_COEFF3 -0x0000092e
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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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static inline int minstrel_filter_avg_add(u16 *prev_1, u16 *prev_2, s32 in)
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{
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s32 out_1 = *prev_1;
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s32 out_2 = *prev_2;
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s32 val;
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if (!in)
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in += 1;
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if (!out_1) {
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val = out_1 = in;
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goto out;
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}
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val = MINSTREL_AVG_COEFF1 * in;
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val += MINSTREL_AVG_COEFF2 * out_1;
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val += MINSTREL_AVG_COEFF3 * out_2;
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val >>= MINSTREL_SCALE;
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if (val > 1 << MINSTREL_SCALE)
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val = 1 << MINSTREL_SCALE;
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if (val < 0)
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val = 1;
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out:
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*prev_2 = out_1;
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*prev_1 = val;
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return val;
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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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u32 att_hist, succ_hist;
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/* prob_avg - moving average of prob */
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u16 prob_avg;
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u16 prob_avg_1;
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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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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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};
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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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bool new_avg;
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u32 sample_switch;
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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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#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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/* Recalculate success probabilities and counters for a given rate using EWMA */
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void minstrel_calc_rate_stats(struct minstrel_priv *mp,
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struct minstrel_rate_stats *mrs);
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int minstrel_get_tp_avg(struct minstrel_rate *mr, int prob_avg);
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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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#endif
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