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wifi: mac80211: factor out part of ieee80211_calc_expected_tx_airtime

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Create ieee80211_rate_expected_tx_airtime helper function, which returns
the expected tx airtime for a given rate and packet length in units of
1/1024 usec, for more accuracy.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://patch.msgid.link/20260724115429.3921457-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Felix Fietkau
2026-07-24 11:54:26 +00:00
committed by Johannes Berg
parent 8e4f5ca8bf
commit 094dc1619c
2 changed files with 56 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files

87
net/mac80211/airtime.c
View File

@@ -685,7 +685,7 @@ static int ieee80211_fill_rx_status(struct ieee80211_rx_status *stat,
if (ieee80211_fill_rate_info(hw, stat, band, ri))
return 0;
if (!ieee80211_rate_valid(rate))
if (!rate || !ieee80211_rate_valid(rate))
return -1;
if (rate->flags & IEEE80211_TX_RC_160_MHZ_WIDTH)
@@ -753,6 +753,53 @@ u32 ieee80211_calc_tx_airtime(struct ieee80211_hw *hw,
}
EXPORT_SYMBOL_GPL(ieee80211_calc_tx_airtime);
u32 ieee80211_rate_expected_tx_airtime(struct ieee80211_hw *hw,
struct ieee80211_tx_rate *tx_rate,
struct rate_info *ri,
enum nl80211_band band,
bool ampdu, int len)
{
struct ieee80211_rx_status stat;
u32 duration, overhead;
u8 agg_shift;
if (ieee80211_fill_rx_status(&stat, hw, tx_rate, ri, band, len))
return 0;
if (stat.encoding == RX_ENC_LEGACY || !ampdu)
return ieee80211_calc_rx_airtime(hw, &stat, len) * 1024;
duration = ieee80211_get_rate_duration(hw, &stat, &overhead);
/*
* Assume that HT/VHT transmission on any AC except VO will
* use aggregation. Since we don't have reliable reporting
* of aggregation length, assume an average size based on the
* tx rate.
* This will not be very accurate, but much better than simply
* assuming un-aggregated tx in all cases.
*/
if (duration > 400 * 1024) /* <= VHT20 MCS2 1S */
agg_shift = 1;
else if (duration > 250 * 1024) /* <= VHT20 MCS3 1S or MCS1 2S */
agg_shift = 2;
else if (duration > 150 * 1024) /* <= VHT20 MCS5 1S or MCS2 2S */
agg_shift = 3;
else if (duration > 70 * 1024) /* <= VHT20 MCS5 2S */
agg_shift = 4;
else if (stat.encoding != RX_ENC_HE ||
duration > 20 * 1024) /* <= HE40 MCS6 2S */
agg_shift = 5;
else
agg_shift = 6;
duration *= len;
duration /= AVG_PKT_SIZE;
duration += (overhead * 1024 >> agg_shift);
return duration;
}
u32 ieee80211_calc_expected_tx_airtime(struct ieee80211_hw *hw,
struct ieee80211_vif *vif,
struct ieee80211_sta *pubsta,
@@ -775,45 +822,13 @@ u32 ieee80211_calc_expected_tx_airtime(struct ieee80211_hw *hw,
if (pubsta) {
struct sta_info *sta = container_of(pubsta, struct sta_info,
sta);
struct ieee80211_rx_status stat;
struct ieee80211_tx_rate *tx_rate = &sta->deflink.tx_stats.last_rate;
struct rate_info *ri = &sta->deflink.tx_stats.last_rate_info;
u32 duration, overhead;
u8 agg_shift;
u32 duration;
if (ieee80211_fill_rx_status(&stat, hw, tx_rate, ri, band, len))
return 0;
if (stat.encoding == RX_ENC_LEGACY || !ampdu)
return ieee80211_calc_rx_airtime(hw, &stat, len);
duration = ieee80211_get_rate_duration(hw, &stat, &overhead);
/*
* Assume that HT/VHT transmission on any AC except VO will
* use aggregation. Since we don't have reliable reporting
* of aggregation length, assume an average size based on the
* tx rate.
* This will not be very accurate, but much better than simply
* assuming un-aggregated tx in all cases.
*/
if (duration > 400 * 1024) /* <= VHT20 MCS2 1S */
agg_shift = 1;
else if (duration > 250 * 1024) /* <= VHT20 MCS3 1S or MCS1 2S */
agg_shift = 2;
else if (duration > 150 * 1024) /* <= VHT20 MCS5 1S or MCS2 2S */
agg_shift = 3;
else if (duration > 70 * 1024) /* <= VHT20 MCS5 2S */
agg_shift = 4;
else if (stat.encoding != RX_ENC_HE ||
duration > 20 * 1024) /* <= HE40 MCS6 2S */
agg_shift = 5;
else
agg_shift = 6;
duration *= len;
duration /= AVG_PKT_SIZE;
duration = ieee80211_rate_expected_tx_airtime(hw, tx_rate, ri,
band, true, len);
duration /= 1024;
duration += (overhead >> agg_shift);
return max_t(u32, duration, 4);
}

5
net/mac80211/ieee80211_i.h
View File

@@ -2937,6 +2937,11 @@ u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
extern const struct ethtool_ops ieee80211_ethtool_ops;
u32 ieee80211_rate_expected_tx_airtime(struct ieee80211_hw *hw,
struct ieee80211_tx_rate *tx_rate,
struct rate_info *ri,
enum nl80211_band band,
bool ampdu, int len);
u32 ieee80211_calc_expected_tx_airtime(struct ieee80211_hw *hw,
struct ieee80211_vif *vif,
struct ieee80211_sta *pubsta,