68 lines
2.1 KiB
Diff
68 lines
2.1 KiB
Diff
From: Felix Fietkau <nbd@nbd.name>
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Date: Wed, 12 Aug 2020 17:07:10 +0200
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Subject: [PATCH] mac80211: improve AQL aggregation estimation for low data
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rates
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Links with low data rates use much smaller aggregates and are much more
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sensitive to latency added by bufferbloat.
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Tune the assumed aggregation length based on the tx rate duration.
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Signed-off-by: Felix Fietkau <nbd@nbd.name>
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---
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--- a/net/mac80211/airtime.c
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+++ b/net/mac80211/airtime.c
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@@ -647,27 +647,41 @@ u32 ieee80211_calc_expected_tx_airtime(s
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if (pubsta) {
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struct sta_info *sta = container_of(pubsta, struct sta_info,
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sta);
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+ struct ieee80211_rx_status stat;
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struct ieee80211_tx_rate *rate = &sta->tx_stats.last_rate;
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struct rate_info *ri = &sta->tx_stats.last_rate_info;
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- u32 airtime;
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+ u32 duration, overhead;
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+ u8 agg_shift;
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- if (!(rate->flags & (IEEE80211_TX_RC_VHT_MCS |
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- IEEE80211_TX_RC_MCS)))
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- ampdu = false;
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+ if (ieee80211_fill_rx_status(&stat, hw, rate, ri, band, len))
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+ return 0;
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+ if (stat.encoding == RX_ENC_LEGACY || !ampdu)
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+ return ieee80211_calc_rx_airtime(hw, &stat, len);
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+
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+ duration = ieee80211_get_rate_duration(hw, &stat, &overhead);
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/*
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* Assume that HT/VHT transmission on any AC except VO will
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* use aggregation. Since we don't have reliable reporting
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- * of aggregation length, assume an average of 16.
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+ * of aggregation length, assume an average size based on the
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+ * tx rate.
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* This will not be very accurate, but much better than simply
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- * assuming un-aggregated tx.
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+ * assuming un-aggregated tx in all cases.
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*/
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- airtime = ieee80211_calc_tx_airtime_rate(hw, rate, ri, band,
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- ampdu ? len * 16 : len);
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- if (ampdu)
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- airtime /= 16;
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+ if (duration > 400) /* <= VHT20 MCS2 1S */
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+ agg_shift = 1;
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+ else if (duration > 250) /* <= VHT20 MCS3 1S or MCS1 2S */
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+ agg_shift = 2;
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+ else if (duration > 150) /* <= VHT20 MCS5 1S or MCS3 2S */
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+ agg_shift = 3;
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+ else
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+ agg_shift = 4;
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+
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+ duration *= len;
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+ duration /= AVG_PKT_SIZE;
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+ duration /= 1024;
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- return airtime;
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+ return duration + (overhead >> agg_shift);
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}
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if (!conf)
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