2019-10-08 17:14:21

by Felix Fietkau

[permalink] [raw]
Subject: [PATCH v2 1/3] mac80211: minstrel: remove divisions in tx status path

Use a slightly different threshold for downgrading spatial streams to
make it easier to calculate without divisions.
Slightly reduces CPU overhead.

Signed-off-by: Felix Fietkau <[email protected]>
---
net/mac80211/rc80211_minstrel.c | 3 +--
net/mac80211/rc80211_minstrel_ht.c | 10 ++++------
2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c
index ee86c3333999..f73017e08111 100644
--- a/net/mac80211/rc80211_minstrel.c
+++ b/net/mac80211/rc80211_minstrel.c
@@ -289,8 +289,7 @@ minstrel_tx_status(void *priv, struct ieee80211_supported_band *sband,
if (mi->sample_deferred > 0)
mi->sample_deferred--;

- if (time_after(jiffies, mi->last_stats_update +
- (mp->update_interval * HZ) / 1000))
+ if (time_after(jiffies, mi->last_stats_update + mp->update_interval))
minstrel_update_stats(mp, mi);
}

diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index 0ef2633349b5..21c74b200269 100644
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -970,23 +970,21 @@ minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
*/
rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
if (rate->attempts > 30 &&
- MINSTREL_FRAC(rate->success, rate->attempts) <
- MINSTREL_FRAC(20, 100)) {
+ rate->success < rate->attempts / 4) {
minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true);
update = true;
}

rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]);
if (rate2->attempts > 30 &&
- MINSTREL_FRAC(rate2->success, rate2->attempts) <
- MINSTREL_FRAC(20, 100)) {
+ rate2->success < rate2->attempts / 4) {
minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false);
update = true;
}
}

if (time_after(jiffies, mi->last_stats_update +
- (mp->update_interval / 2 * HZ) / 1000)) {
+ mp->update_interval / 2)) {
update = true;
minstrel_ht_update_stats(mp, mi, true);
}
@@ -1666,7 +1664,7 @@ minstrel_ht_alloc(struct ieee80211_hw *hw, struct dentry *debugfsdir)
mp->has_mrr = true;

mp->hw = hw;
- mp->update_interval = 100;
+ mp->update_interval = HZ / 10;

#ifdef CONFIG_MAC80211_DEBUGFS
mp->fixed_rate_idx = (u32) -1;
--
2.17.0