From: Felix Fietkau Date: Sat, 23 Jan 2021 07:18:26 +0100 Subject: [PATCH] mac80211: minstrel_ht: remove sample rate switching code for constrained devices This was added to mitigate the effects of too much sampling on devices that use a static global fallback table instead of configurable multi-rate retry. Now that the sampling algorithm is improved, this code path no longer performs any better than the standard probing on affected devices. Signed-off-by: Felix Fietkau --- --- a/net/mac80211/rc80211_minstrel_ht.c +++ b/net/mac80211/rc80211_minstrel_ht.c @@ -648,27 +648,6 @@ __minstrel_ht_get_sample_rate(struct min return 0; } -static void -minstrel_ht_rate_sample_switch(struct minstrel_priv *mp, - struct minstrel_ht_sta *mi) -{ - u16 rate; - - /* - * Use rate switching instead of probing packets for devices with - * little control over retry fallback behavior - */ - if (mp->hw->max_rates > 1) - return; - - rate = __minstrel_ht_get_sample_rate(mi, MINSTREL_SAMPLE_TYPE_INC); - if (!rate) - return; - - mi->sample_rate = rate; - mi->sample_mode = MINSTREL_SAMPLE_ACTIVE; -} - static inline int minstrel_ewma(int old, int new, int weight) { @@ -1012,8 +991,7 @@ minstrel_ht_refill_sample_rates(struct m * higher throughput rates, even if the probablity is a bit lower */ static void -minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, - bool sample) +minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) { struct minstrel_mcs_group_data *mg; struct minstrel_rate_stats *mrs; @@ -1023,18 +1001,6 @@ minstrel_ht_update_stats(struct minstrel u16 index; bool ht_supported = mi->sta->ht_cap.ht_supported; - mi->sample_mode = MINSTREL_SAMPLE_IDLE; - - if (sample) { - mi->total_packets_cur = mi->total_packets - - mi->total_packets_last; - mi->total_packets_last = mi->total_packets; - } - if (!mp->sample_switch) - sample = false; - if (mi->total_packets_cur < SAMPLE_SWITCH_THR && mp->sample_switch != 1) - sample = false; - if (mi->ampdu_packets > 0) { if (!ieee80211_hw_check(mp->hw, TX_STATUS_NO_AMPDU_LEN)) mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len, @@ -1148,16 +1114,12 @@ minstrel_ht_update_stats(struct minstrel minstrel_ht_prob_rate_reduce_streams(mi); minstrel_ht_refill_sample_rates(mi); - if (sample) - minstrel_ht_rate_sample_switch(mp, mi); - #ifdef CPTCFG_MAC80211_DEBUGFS /* use fixed index if set */ if (mp->fixed_rate_idx != -1) { for (i = 0; i < 4; i++) mi->max_tp_rate[i] = mp->fixed_rate_idx; mi->max_prob_rate = mp->fixed_rate_idx; - mi->sample_mode = MINSTREL_SAMPLE_IDLE; } #endif @@ -1247,11 +1209,10 @@ minstrel_ht_tx_status(void *priv, struct struct ieee80211_tx_info *info = st->info; struct minstrel_ht_sta *mi = priv_sta; struct ieee80211_tx_rate *ar = info->status.rates; - struct minstrel_rate_stats *rate, *rate2, *rate_sample = NULL; + struct minstrel_rate_stats *rate, *rate2; struct minstrel_priv *mp = priv; u32 update_interval = mp->update_interval; bool last, update = false; - bool sample_status = false; int i; /* This packet was aggregated but doesn't carry status info */ @@ -1278,49 +1239,18 @@ minstrel_ht_tx_status(void *priv, struct mi->ampdu_packets++; mi->ampdu_len += info->status.ampdu_len; - if (mi->sample_mode != MINSTREL_SAMPLE_IDLE) - rate_sample = minstrel_get_ratestats(mi, mi->sample_rate); - last = !minstrel_ht_txstat_valid(mp, mi, &ar[0]); for (i = 0; !last; i++) { last = (i == IEEE80211_TX_MAX_RATES - 1) || !minstrel_ht_txstat_valid(mp, mi, &ar[i + 1]); rate = minstrel_ht_get_stats(mp, mi, &ar[i]); - if (rate == rate_sample) - sample_status = true; - if (last) rate->success += info->status.ampdu_ack_len; rate->attempts += ar[i].count * info->status.ampdu_len; } - switch (mi->sample_mode) { - case MINSTREL_SAMPLE_IDLE: - if (mp->hw->max_rates > 1 || - mi->total_packets_cur < SAMPLE_SWITCH_THR) - update_interval /= 2; - break; - - case MINSTREL_SAMPLE_ACTIVE: - if (!sample_status) - break; - - mi->sample_mode = MINSTREL_SAMPLE_PENDING; - update = true; - break; - - case MINSTREL_SAMPLE_PENDING: - if (sample_status) - break; - - update = true; - minstrel_ht_update_stats(mp, mi, false); - break; - } - - if (mp->hw->max_rates > 1) { /* * check for sudden death of spatial multiplexing, @@ -1343,7 +1273,7 @@ minstrel_ht_tx_status(void *priv, struct if (time_after(jiffies, mi->last_stats_update + update_interval)) { update = true; - minstrel_ht_update_stats(mp, mi, true); + minstrel_ht_update_stats(mp, mi); } if (update) @@ -1522,18 +1452,14 @@ static void minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) { struct ieee80211_sta_rates *rates; - u16 first_rate = mi->max_tp_rate[0]; int i = 0; - if (mi->sample_mode == MINSTREL_SAMPLE_ACTIVE) - first_rate = mi->sample_rate; - rates = kzalloc(sizeof(*rates), GFP_ATOMIC); if (!rates) return; /* Start with max_tp_rate[0] */ - minstrel_ht_set_rate(mp, mi, rates, i++, first_rate); + minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]); if (mp->hw->max_rates >= 3) { /* At least 3 tx rates supported, use max_tp_rate[1] next */ @@ -1592,11 +1518,6 @@ minstrel_ht_get_rate(void *priv, struct (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO)) return; - if (mp->hw->max_rates == 1 && mp->sample_switch && - (mi->total_packets_cur >= SAMPLE_SWITCH_THR || - mp->sample_switch == 1)) - return; - if (time_is_before_jiffies(mi->sample_time)) return; @@ -1810,7 +1731,7 @@ minstrel_ht_update_caps(void *priv, stru minstrel_ht_update_ofdm(mp, mi, sband, sta); /* create an initial rate table with the lowest supported rates */ - minstrel_ht_update_stats(mp, mi, true); + minstrel_ht_update_stats(mp, mi); minstrel_ht_update_rates(mp, mi); } @@ -1926,8 +1847,6 @@ minstrel_ht_alloc(struct ieee80211_hw *h if (!mp) return NULL; - mp->sample_switch = -1; - /* contention window settings * Just an approximation. Using the per-queue values would complicate * the calculations and is probably unnecessary */ @@ -1947,7 +1866,7 @@ minstrel_ht_alloc(struct ieee80211_hw *h mp->has_mrr = true; mp->hw = hw; - mp->update_interval = HZ / 10; + mp->update_interval = HZ / 20; minstrel_ht_init_cck_rates(mp); for (i = 0; i < ARRAY_SIZE(mp->hw->wiphy->bands); i++) @@ -1965,8 +1884,6 @@ static void minstrel_ht_add_debugfs(stru mp->fixed_rate_idx = (u32) -1; debugfs_create_u32("fixed_rate_idx", S_IRUGO | S_IWUGO, debugfsdir, &mp->fixed_rate_idx); - debugfs_create_u32("sample_switch", S_IRUGO | S_IWUSR, debugfsdir, - &mp->sample_switch); } #endif --- a/net/mac80211/rc80211_minstrel_ht.h +++ b/net/mac80211/rc80211_minstrel_ht.h @@ -75,7 +75,6 @@ struct minstrel_priv { struct ieee80211_hw *hw; bool has_mrr; - u32 sample_switch; unsigned int cw_min; unsigned int cw_max; unsigned int max_retry; @@ -147,12 +146,6 @@ struct minstrel_mcs_group_data { struct minstrel_rate_stats rates[MCS_GROUP_RATES]; }; -enum minstrel_sample_mode { - MINSTREL_SAMPLE_IDLE, - MINSTREL_SAMPLE_ACTIVE, - MINSTREL_SAMPLE_PENDING, -}; - struct minstrel_sample_category { u8 sample_group; u16 sample_rates[MINSTREL_SAMPLE_RATES]; @@ -182,23 +175,19 @@ struct minstrel_ht_sta { unsigned int overhead_legacy; unsigned int overhead_legacy_rtscts; - unsigned int total_packets_last; - unsigned int total_packets_cur; unsigned int total_packets; unsigned int sample_packets; /* tx flags to add for frames for this sta */ u32 tx_flags; - unsigned long sample_time; - struct minstrel_sample_category sample[__MINSTREL_SAMPLE_TYPE_MAX]; + u8 band; u8 sample_seq; - - enum minstrel_sample_mode sample_mode; u16 sample_rate; - u8 band; + unsigned long sample_time; + struct minstrel_sample_category sample[__MINSTREL_SAMPLE_TYPE_MAX]; /* Bitfield of supported MCS rates of all groups */ u16 supported[MINSTREL_GROUPS_NB];