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Commit a0497f9f authored by Felix Fietkau's avatar Felix Fietkau Committed by Johannes Berg
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mac80211/minstrel_ht: add support for using CCK rates 



When MCS rates start to get bad in 2.4 GHz because of long range or
strong interference, CCK rates can be a lot more robust.

This patch adds a pseudo MCS group containing CCK rates (long preamble
in the lower 4 slots, short preamble in the upper slots).

Signed-off-by: default avatarFelix Fietkau <nbd@openwrt.org>
[make minstrel_ht_get_stats static]
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 6719429d

net/mac80211/rc80211_minstrel.c

+29 −0
Original line number Diff line number Diff line
@@ -494,6 +494,33 @@ minstrel_free_sta(void *priv, struct ieee80211_sta *sta, void *priv_sta) 
	kfree(mi);

}



static void

minstrel_init_cck_rates(struct minstrel_priv *mp)

{

	static const int bitrates[4] = { 10, 20, 55, 110 };

	struct ieee80211_supported_band *sband;

	int i, j;



	sband = mp->hw->wiphy->bands[IEEE80211_BAND_2GHZ];

	if (!sband)

		return;



	for (i = 0, j = 0; i < sband->n_bitrates; i++) {

		struct ieee80211_rate *rate = &sband->bitrates[i];



		if (rate->flags & IEEE80211_RATE_ERP_G)

			continue;



		for (j = 0; j < ARRAY_SIZE(bitrates); j++) {

			if (rate->bitrate != bitrates[j])

				continue;



			mp->cck_rates[j] = i;

			break;

		}

	}

}



static void *

minstrel_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)

{
@@ -539,6 +566,8 @@ minstrel_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir) 
			S_IRUGO | S_IWUGO, debugfsdir, &mp->fixed_rate_idx);

#endif



	minstrel_init_cck_rates(mp);



	return mp;

}

net/mac80211/rc80211_minstrel.h

+2 −0
Original line number Diff line number Diff line
@@ -79,6 +79,8 @@ struct minstrel_priv { 
	unsigned int lookaround_rate;

	unsigned int lookaround_rate_mrr;



	u8 cck_rates[4];



#ifdef CONFIG_MAC80211_DEBUGFS

	/*

	 * enable fixed rate processing per RC

net/mac80211/rc80211_minstrel_ht.c

+135 −17
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>

 * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as
@@ -63,6 +63,30 @@ 
	}								\

}



#define CCK_DURATION(_bitrate, _short, _len)		\

	(10 /* SIFS */ +				\

	 (_short ? 72 + 24 : 144 + 48 ) +		\

	 (8 * (_len + 4) * 10) / (_bitrate))



#define CCK_ACK_DURATION(_bitrate, _short)			\

	(CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) +	\

	 CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE))



#define CCK_DURATION_LIST(_short)			\

	CCK_ACK_DURATION(10, _short),			\

	CCK_ACK_DURATION(20, _short),			\

	CCK_ACK_DURATION(55, _short),			\

	CCK_ACK_DURATION(110, _short)



#define CCK_GROUP						\

	[MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS] = {	\

		.streams = 0,					\

		.duration = {					\

			CCK_DURATION_LIST(false),		\

			CCK_DURATION_LIST(true)			\

		}						\

	}



/*

 * To enable sufficiently targeted rate sampling, MCS rates are divided into

 * groups, based on the number of streams and flags (HT40, SGI) that they
@@ -95,8 +119,13 @@ const struct mcs_group minstrel_mcs_groups[] = { 
#if MINSTREL_MAX_STREAMS >= 3

	MCS_GROUP(3, 1, 1),

#endif



	/* must be last */

	CCK_GROUP

};



#define MINSTREL_CCK_GROUP	(ARRAY_SIZE(minstrel_mcs_groups) - 1)



static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES];



/*
@@ -119,6 +148,29 @@ minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate) 
			 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));

}



static struct minstrel_rate_stats *

minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,

		      struct ieee80211_tx_rate *rate)

{

	int group, idx;



	if (rate->flags & IEEE80211_TX_RC_MCS) {

		group = minstrel_ht_get_group_idx(rate);

		idx = rate->idx % MCS_GROUP_RATES;

	} else {

		group = MINSTREL_CCK_GROUP;



		for (idx = 0; idx < ARRAY_SIZE(mp->cck_rates); idx++)

			if (rate->idx == mp->cck_rates[idx])

				break;



		/* short preamble */

		if (!(mi->groups[group].supported & BIT(idx)))

			idx += 4;

	}

	return &mi->groups[group].rates[idx];

}



static inline struct minstrel_rate_stats *

minstrel_get_ratestats(struct minstrel_ht_sta *mi, int index)

{
@@ -159,7 +211,7 @@ static void 
minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)

{

	struct minstrel_rate_stats *mr;

	unsigned int usecs;

	unsigned int usecs = 0;



	mr = &mi->groups[group].rates[rate];
@@ -168,7 +220,9 @@ minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate) 
		return;

	}



	if (group != MINSTREL_CCK_GROUP)

		usecs = mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);



	usecs += minstrel_mcs_groups[group].duration[rate];

	mr->cur_tp = MINSTREL_TRUNC((1000000 / usecs) * mr->probability);

}
@@ -293,7 +347,7 @@ minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 
}



static bool

minstrel_ht_txstat_valid(struct ieee80211_tx_rate *rate)

minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rate)

{

	if (rate->idx < 0)

		return false;
@@ -301,7 +355,13 @@ minstrel_ht_txstat_valid(struct ieee80211_tx_rate *rate) 
	if (!rate->count)

		return false;



	return !!(rate->flags & IEEE80211_TX_RC_MCS);

	if (rate->flags & IEEE80211_TX_RC_MCS)

		return true;



	return rate->idx == mp->cck_rates[0] ||

	       rate->idx == mp->cck_rates[1] ||

	       rate->idx == mp->cck_rates[2] ||

	       rate->idx == mp->cck_rates[3];

}



static void
@@ -386,7 +446,6 @@ minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband, 
	struct minstrel_rate_stats *rate, *rate2;

	struct minstrel_priv *mp = priv;

	bool last;

	int group;

	int i;



	if (!msp->is_ht)
@@ -415,13 +474,12 @@ minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband, 
	if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)

		mi->sample_packets += info->status.ampdu_len;



	last = !minstrel_ht_txstat_valid(&ar[0]);

	last = !minstrel_ht_txstat_valid(mp, &ar[0]);

	for (i = 0; !last; i++) {

		last = (i == IEEE80211_TX_MAX_RATES - 1) ||

		       !minstrel_ht_txstat_valid(&ar[i + 1]);

		       !minstrel_ht_txstat_valid(mp, &ar[i + 1]);



		group = minstrel_ht_get_group_idx(&ar[i]);

		rate = &mi->groups[group].rates[ar[i].idx % 8];

		rate = minstrel_ht_get_stats(mp, mi, &ar[i]);



		if (last)

			rate->success += info->status.ampdu_ack_len;
@@ -447,7 +505,8 @@ minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband, 


	if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000)) {

		minstrel_ht_update_stats(mp, mi);

		if (!(info->flags & IEEE80211_TX_CTL_AMPDU))

		if (!(info->flags & IEEE80211_TX_CTL_AMPDU) &&

		    mi->max_prob_rate / MCS_GROUP_RATES != MINSTREL_CCK_GROUP)

			minstrel_aggr_check(sta, skb);

	}

}
@@ -463,6 +522,7 @@ minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 
	unsigned int ctime = 0;

	unsigned int t_slot = 9; /* FIXME */

	unsigned int ampdu_len = MINSTREL_TRUNC(mi->avg_ampdu_len);

	unsigned int overhead = 0, overhead_rtscts = 0;



	mr = minstrel_get_ratestats(mi, index);

	if (mr->probability < MINSTREL_FRAC(1, 10)) {
@@ -484,9 +544,14 @@ minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 
	ctime += (t_slot * cw) >> 1;

	cw = min((cw << 1) | 1, mp->cw_max);



	if (index / MCS_GROUP_RATES != MINSTREL_CCK_GROUP) {

		overhead = mi->overhead;

		overhead_rtscts = mi->overhead_rtscts;

	}



	/* Total TX time for data and Contention after first 2 tries */

	tx_time = ctime + 2 * (mi->overhead + tx_time_data);

	tx_time_rtscts = ctime + 2 * (mi->overhead_rtscts + tx_time_data);

	tx_time = ctime + 2 * (overhead + tx_time_data);

	tx_time_rtscts = ctime + 2 * (overhead_rtscts + tx_time_data);



	/* See how many more tries we can fit inside segment size */

	do {
@@ -495,8 +560,8 @@ minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 
		cw = min((cw << 1) | 1, mp->cw_max);



		/* Total TX time after this try */

		tx_time += ctime + mi->overhead + tx_time_data;

		tx_time_rtscts += ctime + mi->overhead_rtscts + tx_time_data;

		tx_time += ctime + overhead + tx_time_data;

		tx_time_rtscts += ctime + overhead_rtscts + tx_time_data;



		if (tx_time_rtscts < mp->segment_size)

			mr->retry_count_rtscts++;
@@ -526,9 +591,16 @@ minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, 
	else

		rate->count = mr->retry_count;



	rate->flags = IEEE80211_TX_RC_MCS | group->flags;

	rate->flags = 0;

	if (rtscts)

		rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS;



	if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {

		rate->idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];

		return;

	}



	rate->flags |= IEEE80211_TX_RC_MCS | group->flags;

	rate->idx = index % MCS_GROUP_RATES + (group->streams - 1) * MCS_GROUP_RATES;

}
@@ -591,6 +663,22 @@ minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) 
	return sample_idx;

}



static void

minstrel_ht_check_cck_shortpreamble(struct minstrel_priv *mp,

				    struct minstrel_ht_sta *mi, bool val)

{

	u8 supported = mi->groups[MINSTREL_CCK_GROUP].supported;



	if (!supported || !mi->cck_supported_short)

		return;



	if (supported & (mi->cck_supported_short << (val * 4)))

		return;



	supported ^= mi->cck_supported_short | (mi->cck_supported_short << 4);

	mi->groups[MINSTREL_CCK_GROUP].supported = supported;

}



static void

minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,

                     struct ieee80211_tx_rate_control *txrc)
@@ -610,6 +698,7 @@ minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, 
		return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);



	info->flags |= mi->tx_flags;

	minstrel_ht_check_cck_shortpreamble(mp, mi, txrc->short_preamble);



	/* Don't use EAPOL frames for sampling on non-mrr hw */

	if (mp->hw->max_rates == 1 &&
@@ -682,6 +771,30 @@ minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, 
	}

}



static void

minstrel_ht_update_cck(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,

		       struct ieee80211_supported_band *sband,

		       struct ieee80211_sta *sta)

{

	int i;



	if (sband->band != IEEE80211_BAND_2GHZ)

		return;



	mi->cck_supported = 0;

	mi->cck_supported_short = 0;

	for (i = 0; i < 4; i++) {

		if (!rate_supported(sta, sband->band, mp->cck_rates[i]))

			continue;



		mi->cck_supported |= BIT(i);

		if (sband->bitrates[i].flags & IEEE80211_RATE_SHORT_PREAMBLE)

			mi->cck_supported_short |= BIT(i);

	}



	mi->groups[MINSTREL_CCK_GROUP].supported = mi->cck_supported;

}



static void

minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,

                        struct ieee80211_sta *sta, void *priv_sta)
@@ -702,7 +815,7 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband, 
		goto use_legacy;



	BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=

		MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS);

		MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1);



	msp->is_ht = true;

	memset(mi, 0, sizeof(*mi));
@@ -738,6 +851,11 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband, 
		u16 req = 0;



		mi->groups[i].supported = 0;

		if (i == MINSTREL_CCK_GROUP) {

			minstrel_ht_update_cck(mp, mi, sband, sta);

			continue;

		}



		if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI) {

			if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)

				req |= IEEE80211_HT_CAP_SGI_40;

net/mac80211/rc80211_minstrel_ht.h

+4 −1
Original line number Diff line number Diff line
@@ -107,8 +107,11 @@ struct minstrel_ht_sta { 
	/* current MCS group to be sampled */

	u8 sample_group;



	u8 cck_supported;

	u8 cck_supported_short;



	/* MCS rate group info and statistics */

	struct minstrel_mcs_group_data groups[MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS];

	struct minstrel_mcs_group_data groups[MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS + 1];

};



struct minstrel_ht_sta_priv {

net/mac80211/rc80211_minstrel_ht_debugfs.c

+67 −42
Original line number Diff line number Diff line
@@ -15,57 +15,48 @@ 
#include "rc80211_minstrel.h"

#include "rc80211_minstrel_ht.h"



static int

minstrel_ht_stats_open(struct inode *inode, struct file *file)

static char *

minstrel_ht_stats_dump(struct minstrel_ht_sta *mi, int i, char *p)

{

	struct minstrel_ht_sta_priv *msp = inode->i_private;

	struct minstrel_ht_sta *mi = &msp->ht;

	struct minstrel_debugfs_info *ms;

	unsigned int i, j, tp, prob, eprob;

	char *p;

	int ret;



	if (!msp->is_ht) {

		inode->i_private = &msp->legacy;

		ret = minstrel_stats_open(inode, file);

		inode->i_private = msp;

		return ret;

	}



	ms = kmalloc(sizeof(*ms) + 8192, GFP_KERNEL);

	if (!ms)

		return -ENOMEM;



	file->private_data = ms;

	p = ms->buf;

	p += sprintf(p, "type         rate     throughput  ewma prob   this prob  "

			"retry   this succ/attempt   success    attempts\n");

	for (i = 0; i < MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS; i++) {

	unsigned int max_mcs = MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS;

	const struct mcs_group *mg;

	unsigned int j, tp, prob, eprob;

	char htmode = '2';

	char gimode = 'L';



	if (!mi->groups[i].supported)

			continue;

		return p;



		if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)

	mg = &minstrel_mcs_groups[i];

	if (mg->flags & IEEE80211_TX_RC_40_MHZ_WIDTH)

		htmode = '4';

		if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_SHORT_GI)

	if (mg->flags & IEEE80211_TX_RC_SHORT_GI)

		gimode = 'S';



	for (j = 0; j < MCS_GROUP_RATES; j++) {

		struct minstrel_rate_stats *mr = &mi->groups[i].rates[j];

		static const int bitrates[4] = { 10, 20, 55, 110 };

		int idx = i * MCS_GROUP_RATES + j;



		if (!(mi->groups[i].supported & BIT(j)))

			continue;



		if (i == max_mcs)

			p += sprintf(p, "CCK/%cP   ", j < 4 ? 'L' : 'S');

		else

			p += sprintf(p, "HT%c0/%cGI ", htmode, gimode);



		*(p++) = (idx == mi->max_tp_rate) ? 'T' : ' ';

		*(p++) = (idx == mi->max_tp_rate2) ? 't' : ' ';

		*(p++) = (idx == mi->max_prob_rate) ? 'P' : ' ';

			p += sprintf(p, " MCS%-2u", (minstrel_mcs_groups[i].streams - 1) *



		if (i == max_mcs) {

			int r = bitrates[j % 4];

			p += sprintf(p, " %2u.%1uM", r / 10, r % 10);

		} else {

			p += sprintf(p, " MCS%-2u", (mg->streams - 1) *

					 MCS_GROUP_RATES + j);

		}



		tp = mr->cur_tp / 10;

		prob = MINSTREL_TRUNC(mr->cur_prob * 1000);
@@ -82,7 +73,41 @@ minstrel_ht_stats_open(struct inode *inode, struct file *file) 
				(unsigned long long)mr->succ_hist,

				(unsigned long long)mr->att_hist);

	}



	return p;

}



static int

minstrel_ht_stats_open(struct inode *inode, struct file *file)

{

	struct minstrel_ht_sta_priv *msp = inode->i_private;

	struct minstrel_ht_sta *mi = &msp->ht;

	struct minstrel_debugfs_info *ms;

	unsigned int i;

	unsigned int max_mcs = MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS;

	char *p;

	int ret;



	if (!msp->is_ht) {

		inode->i_private = &msp->legacy;

		ret = minstrel_stats_open(inode, file);

		inode->i_private = msp;

		return ret;

	}



	ms = kmalloc(sizeof(*ms) + 8192, GFP_KERNEL);

	if (!ms)

		return -ENOMEM;



	file->private_data = ms;

	p = ms->buf;

	p += sprintf(p, "type         rate     throughput  ewma prob   this prob  "

			"retry   this succ/attempt   success    attempts\n");



	p = minstrel_ht_stats_dump(mi, max_mcs, p);

	for (i = 0; i < max_mcs; i++)

		p = minstrel_ht_stats_dump(mi, i, p);



	p += sprintf(p, "\nTotal packet count::    ideal %d      "

			"lookaround %d\n",

			max(0, (int) mi->total_packets - (int) mi->sample_packets),