mac80211: simplify minstrel_ht code, rewrite packet sampling algorithm for improved performance and a-mpdu length
SVN-Revision: 20035
This commit is contained in:
parent
05ca2b606a
commit
a12048b2bf
1 changed files with 107 additions and 126 deletions
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@ -68,7 +68,7 @@
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--- /dev/null
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+++ b/net/mac80211/rc80211_minstrel_ht.c
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@@ -0,0 +1,824 @@
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@@ -0,0 +1,800 @@
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+/*
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+ * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
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+ *
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@ -125,9 +125,6 @@
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+ } \
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+}
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+
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+#define MINSTREL_INTFL_SAMPLE_SLOT0 BIT(30)
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+#define MINSTREL_INTFL_SAMPLE_SLOT1 BIT(31)
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+
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+/*
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+ * To enable sufficiently targeted rate sampling, MCS rates are divided into
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+ * groups, based on the number of streams and flags (HT40, SGI) that they
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@ -206,7 +203,8 @@
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+static void
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+minstrel_calc_rate_ewma(struct minstrel_priv *mp, struct minstrel_rate_stats *mr)
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+{
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+ if (mr->attempts) {
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+ if (unlikely(mr->attempts > 0)) {
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+ mr->sample_skipped = 0;
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+ mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts);
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+ if (!mr->att_hist)
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+ mr->probability = mr->cur_prob;
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@ -215,6 +213,8 @@
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+ mr->cur_prob, EWMA_LEVEL);
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+ mr->att_hist += mr->attempts;
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+ mr->succ_hist += mr->success;
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+ } else {
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+ mr->sample_skipped++;
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+ }
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+ mr->last_success = mr->success;
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+ mr->last_attempts = mr->attempts;
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@ -262,6 +262,7 @@
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+ int cur_prob, cur_prob_tp, cur_tp, cur_tp2;
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+ int group, i, index;
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+
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+ mi->sample_count = 0;
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+ mi->max_tp_rate = 0;
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+ mi->max_tp_rate2 = 0;
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+ mi->max_prob_rate = 0;
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@ -279,6 +280,7 @@
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+ mg->max_tp_rate = 0;
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+ mg->max_tp_rate2 = 0;
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+ mg->max_prob_rate = 0;
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+ mi->sample_count++;
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+
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+ for (i = 0; i < MCS_GROUP_RATES; i++) {
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+ if (!(mg->supported & BIT(i)))
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@ -309,7 +311,7 @@
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+ mr = minstrel_get_ratestats(mi, index);
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+ }
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+
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+ if (index == mg->max_tp_rate)
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+ if (index >= mg->max_tp_rate)
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+ continue;
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+
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+ if (mr->cur_tp > cur_tp2) {
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@ -319,6 +321,9 @@
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+ }
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+ }
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+
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+ /* try to sample up to half of the availble rates during each interval */
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+ mi->sample_count *= 4;
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+
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+ cur_prob = 0;
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+ cur_prob_tp = 0;
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+ cur_tp = 0;
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@ -386,7 +391,7 @@
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+}
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+
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+static void
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+minstrel_downgrade_rate(struct minstrel_ht_sta *mi, int *idx, int type)
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+minstrel_downgrade_rate(struct minstrel_ht_sta *mi, int *idx, bool primary)
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+{
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+ int group, orig_group;
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+
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@ -397,18 +402,14 @@
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+ if (!mi->groups[group].supported)
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+ continue;
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+
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+ if (minstrel_mcs_groups[group].streams >=
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+ if (minstrel_mcs_groups[group].streams >
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+ minstrel_mcs_groups[orig_group].streams)
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+ continue;
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+
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+ switch(type) {
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+ case 0:
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+ if (primary)
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+ *idx = mi->groups[group].max_tp_rate;
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+ break;
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+ case 1:
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+ else
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+ *idx = mi->groups[group].max_tp_rate2;
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+ break;
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+ }
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+ break;
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+ }
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+}
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@ -445,6 +446,17 @@
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+ mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
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+ MINSTREL_FRAC(info->status.ampdu_len, 1), 90);
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+
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+ if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
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+ mi->sample_wait = 4 + MINSTREL_TRUNC(mi->avg_ampdu_len);
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+ mi->sample_tries = 3;
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+ mi->sample_count--;
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+ }
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+
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+ if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) {
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+ mi->sample_packets += info->status.ampdu_len;
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+ minstrel_next_sample_idx(mi);
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+ }
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+
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+ for (i = 0; !last; i++) {
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+ last = (i == IEEE80211_TX_MAX_RATES - 1) ||
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+ !minstrel_ht_txstat_valid(&ar[i + 1]);
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@ -452,14 +464,6 @@
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+ if (!minstrel_ht_txstat_valid(&ar[i]))
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+ break;
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+
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+ if ((i == 0 && (info->flags & MINSTREL_INTFL_SAMPLE_SLOT0)) ||
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+ (i == 1 && (info->flags & MINSTREL_INTFL_SAMPLE_SLOT1))) {
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+ if (mi->sample_pending > 0)
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+ mi->sample_pending--;
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+ mi->sample_packets++;
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+ minstrel_next_sample_idx(mi);
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+ }
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+
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+ group = minstrel_ht_get_group_idx(&ar[i]);
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+ rate = &mi->groups[group].rates[ar[i].idx % 8];
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+
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@ -469,20 +473,19 @@
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+ rate->attempts += ar[i].count * info->status.ampdu_len;
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+ }
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+
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+
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+ /*
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+ * check for sudden death of spatial multiplexing,
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+ * downgrade to a lower number of streams if necessary.
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+ */
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+ rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
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+ if (MINSTREL_FRAC(rate->success, rate->attempts) <
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+ MINSTREL_FRAC(20, 100) && rate->attempts > 15)
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+ minstrel_downgrade_rate(mi, &mi->max_tp_rate, 0);
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+ MINSTREL_FRAC(20, 100) && rate->attempts > 30)
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+ minstrel_downgrade_rate(mi, &mi->max_tp_rate, true);
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+
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+ rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
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+ if (MINSTREL_FRAC(rate->success, rate->attempts) <
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+ MINSTREL_FRAC(20, 100) && rate->attempts > 15)
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+ minstrel_downgrade_rate(mi, &mi->max_tp_rate2, 1);
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+ MINSTREL_FRAC(20, 100) && rate->attempts > 30)
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+ minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false);
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+
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+ if (time_after(jiffies, mi->stats_update + (mp->update_interval / 2 * HZ) / 1000))
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+ minstrel_ht_update_stats(mp, mi);
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@ -560,41 +563,21 @@
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+}
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+
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+static int
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+minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
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+ bool *defer)
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+minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
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+{
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+ struct minstrel_rate_stats *mr;
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+ struct minstrel_mcs_group_data *mg;
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+ int sample_idx = 0;
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+ int sample_rate;
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+ int delta;
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+
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+ if (mp->has_mrr)
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+ sample_rate = mp->lookaround_rate_mrr;
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+ else
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+ sample_rate = mp->lookaround_rate;
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+
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+ delta = (mi->total_packets * sample_rate) / 100 - mi->sample_packets;
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+ delta -= mi->sample_pending / 2;
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+
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+ if (delta <= 0)
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+ if (mi->sample_wait > 0) {
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+ mi->sample_wait--;
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+ return -1;
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+
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+ delta -= 16;
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+ if (delta > 1) {
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+ /* With multi-rate retry, not every planned sample
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+ * attempt actually gets used, due to the way the retry
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+ * chain is set up - [max_tp,sample,prob,lowest] for
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+ * sample_rate < max_tp.
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+ *
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+ * If there's too much sampling backlog and the link
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+ * starts getting worse, minstrel would start bursting
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+ * out lots of sampling frames, which would result
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+ * in a large throughput loss.
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+ */
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+ mi->sample_packets += delta - 1;
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+ }
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+
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+ if (!mi->sample_tries)
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+ return -1;
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+
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+ mi->sample_tries--;
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+ mg = &mi->groups[mi->sample_group];
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+ sample_idx = sample_table[mg->column][mg->index];
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+ mr = &mg->rates[sample_idx];
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@ -605,27 +588,22 @@
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+ * higher than 95% to avoid wasting airtime
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+ */
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+ if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100)))
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+ return -1;
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+ goto next;
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+
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+ /*
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+ * Make sure that lower rates get sampled only occasionally,
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+ * if the link is working perfectly.
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+ */
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+ if (minstrel_get_duration(sample_idx) >
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+ minstrel_get_duration(mi->max_tp_rate)) {
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+ /*
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+ * Make sure that lower rates get sampled occasionally, even
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+ * if the link is working perfectly. Some drivers such as ath9k
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+ * severely limit aggregation size if the MRR chain contains low
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+ * rates
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+ *
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+ * If the lower rate has already been tried a few times, there's
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+ * no point in forcing it to be sampled again, so skip to the
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+ * next sampling index after applying this one in the tx control
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+ */
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+ if (mr->att_hist > 15) {
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+ *defer = true;
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+ minstrel_next_sample_idx(mi);
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+ }
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+ }
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+ minstrel_get_duration(mi->max_tp_rate) &&
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+ mr->sample_skipped < 10)
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+ goto next;
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+
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+ return sample_idx;
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+
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+next:
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+ minstrel_next_sample_idx(mi);
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+ return -1;
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+}
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+
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+static void
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@ -657,7 +635,6 @@
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+ struct minstrel_ht_sta_priv *msp = priv_sta;
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+ struct minstrel_ht_sta *mi = &msp->ht;
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+ struct minstrel_priv *mp = priv;
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+ bool sample_defer = false;
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+ int sample_idx;
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+
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+ if (rate_control_send_low(sta, priv_sta, txrc))
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@ -668,22 +645,13 @@
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+
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+ minstrel_aggr_check(mp, sta, txrc->skb);
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+
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+ sample_idx = minstrel_get_sample_rate(mp, mi, &sample_defer);
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+ sample_idx = minstrel_get_sample_rate(mp, mi);
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+ if (sample_idx >= 0) {
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+ if (sample_defer) {
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+ minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate,
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+ txrc, false, false);
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+ minstrel_ht_set_rate(mp, mi, &ar[1], sample_idx,
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+ txrc, true, true);
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+ info->flags |= MINSTREL_INTFL_SAMPLE_SLOT1;
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+ } else {
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+ minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx,
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+ txrc, true, false);
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+ minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate,
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+ txrc, false, true);
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+ info->flags |= MINSTREL_INTFL_SAMPLE_SLOT0;
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+ }
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+ mi->sample_pending++;
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+ minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx,
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+ txrc, true, false);
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+ minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate,
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+ txrc, false, true);
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+ info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
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+ } else {
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+ minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate,
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+ txrc, false, false);
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@ -698,21 +666,58 @@
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+ mi->total_packets++;
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+
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+ /* wraparound */
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+ if (mi->total_packets >= 100000) {
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+ if (mi->total_packets == ~0) {
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+ mi->total_packets = 0;
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+ mi->sample_packets = 0;
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+ mi->sample_pending = 0;
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+ }
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+}
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+
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+static void
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+minstrel_ht_update_cap(struct minstrel_ht_sta *mi, struct ieee80211_sta *sta,
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+ enum nl80211_channel_type oper_chan_type)
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+minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
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+ struct ieee80211_sta *sta, void *priv_sta,
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+ enum nl80211_channel_type oper_chan_type)
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+{
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+ struct minstrel_priv *mp = priv;
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+ struct minstrel_ht_sta_priv *msp = priv_sta;
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+ struct minstrel_ht_sta *mi = &msp->ht;
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+ struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
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+ struct ieee80211_local *local = hw_to_local(mp->hw);
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+ u16 sta_cap = sta->ht_cap.cap;
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+ int ack_dur;
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+ int i;
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+
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+ /* fall back to the old minstrel for legacy stations */
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+ if (sta && !sta->ht_cap.ht_supported) {
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+ msp->is_ht = false;
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+ memset(&msp->legacy, 0, sizeof(msp->legacy));
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+ msp->legacy.r = msp->ratelist;
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+ msp->legacy.sample_table = msp->sample_table;
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+ return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy);
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+ }
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+
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+ BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
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+ MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS);
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+
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+ msp->is_ht = true;
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+ memset(mi, 0, sizeof(*mi));
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+ mi->stats_update = jiffies;
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+
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+ ack_dur = ieee80211_frame_duration(local, 10, 60, 1, 1);
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+ mi->overhead = ieee80211_frame_duration(local, 0, 60, 1, 1) + ack_dur;
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+ mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
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+
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+ mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
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+
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+ /* When using MRR, sample more on the first attempt, without delay */
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+ if (mp->has_mrr) {
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+ mi->sample_count = 16;
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+ mi->sample_wait = 0;
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+ } else {
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+ mi->sample_count = 8;
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+ mi->sample_wait = 8;
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+ }
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+ mi->sample_tries = 4;
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+
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+ if (oper_chan_type != NL80211_CHAN_HT40MINUS &&
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+ oper_chan_type != NL80211_CHAN_HT40PLUS)
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+ sta_cap &= ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
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@ -744,34 +749,8 @@
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+ struct ieee80211_sta *sta, void *priv_sta)
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+{
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+ struct minstrel_priv *mp = priv;
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+ struct minstrel_ht_sta_priv *msp = priv_sta;
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+ struct minstrel_ht_sta *mi = &msp->ht;
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+ struct ieee80211_local *local = hw_to_local(mp->hw);
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+ int ack_dur;
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+
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+ /* fall back to the old minstrel for legacy stations */
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+ if (sta && !sta->ht_cap.ht_supported) {
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+ msp->is_ht = false;
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+ memset(&msp->legacy, 0, sizeof(msp->legacy));
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+ msp->legacy.r = msp->ratelist;
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+ msp->legacy.sample_table = msp->sample_table;
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+ return mac80211_minstrel.rate_init(priv, sband, sta, &msp->legacy);
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+ }
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+
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+ BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) !=
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+ MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS);
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+
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+ msp->is_ht = true;
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+ memset(mi, 0, sizeof(*mi));
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+ mi->stats_update = jiffies;
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+
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+ ack_dur = ieee80211_frame_duration(local, 10, 60, 1, 1);
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+ mi->overhead = ieee80211_frame_duration(local, 0, 60, 1, 1) + ack_dur;
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+ mi->overhead_rtscts = mi->overhead + 2 * ack_dur;
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+
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+ mi->avg_ampdu_len = MINSTREL_FRAC(1, 1);
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+
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+ minstrel_ht_update_cap(mi, sta, mp->hw->conf.channel_type);
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+ minstrel_ht_update_caps(priv, sband, sta, priv_sta, mp->hw->conf.channel_type);
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+}
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+
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+static void
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@ -779,10 +758,7 @@
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+ struct ieee80211_sta *sta, void *priv_sta,
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+ u32 changed, enum nl80211_channel_type oper_chan_type)
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+{
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+ struct minstrel_ht_sta_priv *msp = priv_sta;
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+ struct minstrel_ht_sta *mi = &msp->ht;
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+
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+ minstrel_ht_update_cap(mi, sta, oper_chan_type);
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+ minstrel_ht_update_caps(priv, sband, sta, priv_sta, oper_chan_type);
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+}
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+
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+static void *
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@ -895,7 +871,7 @@
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+}
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--- /dev/null
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+++ b/net/mac80211/rc80211_minstrel_ht.h
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@@ -0,0 +1,115 @@
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@@ -0,0 +1,120 @@
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+/*
|
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+ * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
|
||||
+ *
|
||||
|
@ -942,9 +918,11 @@
|
|||
+ unsigned int cur_prob, probability;
|
||||
+
|
||||
+ /* maximum retry counts */
|
||||
+ bool retry_updated;
|
||||
+ unsigned int retry_count;
|
||||
+ unsigned int retry_count_rtscts;
|
||||
+
|
||||
+ bool retry_updated;
|
||||
+ u8 sample_skipped;
|
||||
+};
|
||||
+
|
||||
+struct minstrel_mcs_group_data {
|
||||
|
@ -985,10 +963,13 @@
|
|||
+
|
||||
+ unsigned int total_packets;
|
||||
+ unsigned int sample_packets;
|
||||
+ unsigned int sample_pending;
|
||||
+
|
||||
+ u8 sample_wait;
|
||||
+ u8 sample_tries;
|
||||
+ u8 sample_count;
|
||||
+
|
||||
+ /* current MCS group to be sampled */
|
||||
+ unsigned int sample_group;
|
||||
+ u8 sample_group;
|
||||
+
|
||||
+ /* MCS rate group info and statistics */
|
||||
+ struct minstrel_mcs_group_data groups[MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS];
|
||||
|
|
Loading…
Reference in a new issue