Commit c0eb09aa authored by Felix Fietkau's avatar Felix Fietkau Committed by Johannes Berg
Browse files

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: default avatarFelix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210127055735.78599-6-nbd@nbd.name


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 4a8d0c99

net/mac80211/rc80211_minstrel_ht.c

+6 −89
Original line number Diff line number Diff line
@@ -648,27 +648,6 @@ __minstrel_ht_get_sample_rate(struct minstrel_ht_sta *mi, 
	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 minstrel_ht_sta *mi) 
 *    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_priv *mp, struct minstrel_ht_sta *mi, 
	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_priv *mp, struct minstrel_ht_sta *mi, 
	minstrel_ht_prob_rate_reduce_streams(mi);

	minstrel_ht_refill_sample_rates(mi);



	if (sample)

		minstrel_ht_rate_sample_switch(mp, mi);



#ifdef CONFIG_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 ieee80211_supported_band *sband, 
	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 ieee80211_supported_band *sband, 
	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 ieee80211_supported_band *sband, 


	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 ieee80211_sta *sta, void *priv_sta, 
	    (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, struct ieee80211_supported_band *sband, 
	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 *hw) 
	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 *hw) 
		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(struct ieee80211_hw *hw, void *priv, 
	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

net/mac80211/rc80211_minstrel_ht.h

+3 −14
Original line number Diff line number Diff line
@@ -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];