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mac80211: minstrel_ht - reduce the overhead of rate sampling
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- reduce the number of retransmission attempts for sample rates
- sample lower rates less often
- do not use RTS/CTS for sampling frames
- increase the time between sampling attempts

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Felix Fietkau authored and John W. Linville committed Nov 15, 2010
1 parent ff32d9c commit c7317e4
Showing 1 changed file with 10 additions and 6 deletions.
16 changes: 10 additions & 6 deletions net/mac80211/rc80211_minstrel_ht.c
Original file line number Diff line number Diff line change
Expand Up @@ -407,8 +407,8 @@ minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
mi->ampdu_len += info->status.ampdu_len;

if (!mi->sample_wait && !mi->sample_tries && mi->sample_count > 0) {
mi->sample_wait = 4 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
mi->sample_tries = 3;
mi->sample_wait = 16 + 2 * MINSTREL_TRUNC(mi->avg_ampdu_len);
mi->sample_tries = 2;
mi->sample_count--;
}

Expand Down Expand Up @@ -506,7 +506,9 @@ minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
if (!mr->retry_updated)
minstrel_calc_retransmit(mp, mi, index);

if (mr->probability < MINSTREL_FRAC(20, 100))
if (sample)
rate->count = 1;
else if (mr->probability < MINSTREL_FRAC(20, 100))
rate->count = 2;
else if (rtscts)
rate->count = mr->retry_count_rtscts;
Expand Down Expand Up @@ -562,7 +564,7 @@ minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
*/
if (minstrel_get_duration(sample_idx) >
minstrel_get_duration(mi->max_tp_rate)) {
if (mr->sample_skipped < 10)
if (mr->sample_skipped < 20)
goto next;

if (mi->sample_slow++ > 2)
Expand All @@ -586,6 +588,7 @@ minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
struct minstrel_ht_sta *mi = &msp->ht;
struct minstrel_priv *mp = priv;
int sample_idx;
bool sample = false;

if (rate_control_send_low(sta, priv_sta, txrc))
return;
Expand All @@ -596,18 +599,19 @@ minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
info->flags |= mi->tx_flags;
sample_idx = minstrel_get_sample_rate(mp, mi);
if (sample_idx >= 0) {
sample = true;
minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx,
txrc, true, false);
minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate,
txrc, false, true);
txrc, false, false);
info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
} else {
minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate,
txrc, false, false);
minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2,
txrc, false, true);
}
minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, txrc, false, true);
minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, txrc, false, !sample);

ar[3].count = 0;
ar[3].idx = -1;
Expand Down

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