On Fri, Feb 8, 2013 at 4:38 AM, Felix Fietkau <nbd@xxxxxxxxxxx> wrote:
>
> 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: Felix Fietkau <nbd@xxxxxxxxxxx>
> ---
> net/mac80211/rc80211_minstrel.c | 29 ++++++
> net/mac80211/rc80211_minstrel.h | 2 +
> net/mac80211/rc80211_minstrel_ht.c | 152 +++++++++++++++++++++++++----
> net/mac80211/rc80211_minstrel_ht.h | 5 +-
> net/mac80211/rc80211_minstrel_ht_debugfs.c | 109 +++++++++++++--------
> 5 files changed, 237 insertions(+), 60 deletions(-)
>
> diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c
> index 8c5acdc..eea45a2 100644
> --- a/net/mac80211/rc80211_minstrel.c
> +++ b/net/mac80211/rc80211_minstrel.c
> @@ -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;
> }
>
> diff --git a/net/mac80211/rc80211_minstrel.h b/net/mac80211/rc80211_minstrel.h
> index 5d278ec..5ecf757 100644
> --- a/net/mac80211/rc80211_minstrel.h
> +++ b/net/mac80211/rc80211_minstrel.h
> @@ -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
> diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
> index 5bb316a..ba32416 100644
> --- a/net/mac80211/rc80211_minstrel_ht.c
> +++ b/net/mac80211/rc80211_minstrel_ht.c
> @@ -1,5 +1,5 @@
> /*
> - * Copyright (C) 2010 Felix Fietkau <nbd@xxxxxxxxxxx>
> + * Copyright (C) 2010-2013 Felix Fietkau <nbd@xxxxxxxxxxx>
> *
> * 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 \
> + { \
> + .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));
> }
>
> +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 == idx)
> + break;
Either this if statement isn't doing what you think it does (perhaps
you wanted rate->idx == mp->cck_rates[i]?) or this whole loop could be
simplified with an if statement?
> +
> + /* 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;
> }
>
> - usecs = mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
> + 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;
> }
>
> @@ -592,6 +664,22 @@ minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
> }
>
> 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 &&
> @@ -683,6 +772,30 @@ 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;
> diff --git a/net/mac80211/rc80211_minstrel_ht.h b/net/mac80211/rc80211_minstrel_ht.h
> index 462d2b2..302dbd5 100644
> --- a/net/mac80211/rc80211_minstrel_ht.h
> +++ b/net/mac80211/rc80211_minstrel_ht.h
> @@ -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 {
> diff --git a/net/mac80211/rc80211_minstrel_ht_debugfs.c b/net/mac80211/rc80211_minstrel_ht_debugfs.c
> index f2b7d26..df44a5a 100644
> --- a/net/mac80211/rc80211_minstrel_ht_debugfs.c
> +++ b/net/mac80211/rc80211_minstrel_ht_debugfs.c
> @@ -15,13 +15,76 @@
> #include "rc80211_minstrel.h"
> #include "rc80211_minstrel_ht.h"
>
> +static char *
> +minstrel_ht_stats_dump(struct minstrel_ht_sta *mi, int i, char *p)
> +{
> + 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)
> + return p;
> +
> + mg = &minstrel_mcs_groups[i];
> + if (mg->flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
> + htmode = '4';
> + 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' : ' ';
> +
> + 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);
> + eprob = MINSTREL_TRUNC(mr->probability * 1000);
> +
> + p += sprintf(p, " %6u.%1u %6u.%1u %6u.%1u "
> + "%3u %3u(%3u) %8llu %8llu\n",
> + tp / 10, tp % 10,
> + eprob / 10, eprob % 10,
> + prob / 10, prob % 10,
> + mr->retry_count,
> + mr->last_success,
> + mr->last_attempts,
> + (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, j, tp, prob, eprob;
> + unsigned int i;
> + unsigned int max_mcs = MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS;
> char *p;
> int ret;
>
> @@ -40,49 +103,11 @@ minstrel_ht_stats_open(struct inode *inode, struct file *file)
> 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++) {
> - char htmode = '2';
> - char gimode = 'L';
> -
> - if (!mi->groups[i].supported)
> - continue;
> -
> - if (minstrel_mcs_groups[i].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
> - htmode = '4';
> - if (minstrel_mcs_groups[i].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];
> - int idx = i * MCS_GROUP_RATES + j;
> + p = minstrel_ht_stats_dump(mi, max_mcs, p);
> + for (i = 0; i < max_mcs; i++)
> + p = minstrel_ht_stats_dump(mi, i, p);
>
> - if (!(mi->groups[i].supported & BIT(j)))
> - continue;
> -
> - 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) *
> - MCS_GROUP_RATES + j);
> -
> - tp = mr->cur_tp / 10;
> - prob = MINSTREL_TRUNC(mr->cur_prob * 1000);
> - eprob = MINSTREL_TRUNC(mr->probability * 1000);
> -
> - p += sprintf(p, " %6u.%1u %6u.%1u %6u.%1u "
> - "%3u %3u(%3u) %8llu %8llu\n",
> - tp / 10, tp % 10,
> - eprob / 10, eprob % 10,
> - prob / 10, prob % 10,
> - mr->retry_count,
> - mr->last_success,
> - mr->last_attempts,
> - (unsigned long long)mr->succ_hist,
> - (unsigned long long)mr->att_hist);
> - }
> - }
> p += sprintf(p, "\nTotal packet count:: ideal %d "
> "lookaround %d\n",
> max(0, (int) mi->total_packets - (int) mi->sample_packets),
> --
> 1.8.0.2
>
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