From: Toke Høiland-Jørgensen <[email protected]>
This switches the airtime scheduler in mac80211 to use a virtual time-based
scheduler instead of the round-robin scheduler used before. This has a
couple of advantages:
- No need to sync up the round-robin scheduler in firmware/hardware with
the round-robin airtime scheduler.
- If several stations are eligible for transmission we can schedule both of
them; no need to hard-block the scheduling rotation until the head of the
queue has used up its quantum.
- The check of whether a station is eligible for transmission becomes
simpler (in ieee80211_txq_may_transmit()).
The drawback is that scheduling becomes slightly more expensive, as we need
to maintain an rbtree of TXQs sorted by virtual time. This means that
ieee80211_register_airtime() becomes O(logN) in the number of currently
scheduled TXQs. However, hopefully this number rarely grows too big (it's
only TXQs currently backlogged, not all associated stations), so it
shouldn't be too big of an issue.
Signed-off-by: Toke Høiland-Jørgensen <[email protected]>
---
net/mac80211/debugfs.c | 48 +++++++++-
net/mac80211/debugfs_sta.c | 16 ++--
net/mac80211/ieee80211_i.h | 14 ++-
net/mac80211/main.c | 2 +-
net/mac80211/sta_info.c | 19 +++-
net/mac80211/sta_info.h | 3 +-
net/mac80211/tx.c | 217 +++++++++++++++++++++++++++++----------------
7 files changed, 223 insertions(+), 96 deletions(-)
diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index 2d43bc1..4847168 100644
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -150,6 +150,46 @@ static ssize_t aqm_write(struct file *file,
.llseek = default_llseek,
};
+static ssize_t airtime_read(struct file *file,
+ char __user *user_buf,
+ size_t count,
+ loff_t *ppos)
+{
+ struct ieee80211_local *local = file->private_data;
+ char buf[200];
+ u64 v_t[IEEE80211_NUM_ACS];
+ u64 wt[IEEE80211_NUM_ACS];
+ int len = 0, ac;
+
+ for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
+ spin_lock_bh(&local->active_txq_lock[ac]);
+ v_t[ac] = local->airtime_v_t[ac];
+ wt[ac] = local->airtime_weight_sum[ac];
+ spin_unlock_bh(&local->active_txq_lock[ac]);
+ }
+ len = scnprintf(buf, sizeof(buf),
+ "\tVO VI BE BK\n"
+ "Virt-t\t%-10llu %-10llu %-10llu %-10llu\n"
+ "Weight\t%-10llu %-10llu %-10llu %-10llu\n",
+ v_t[0],
+ v_t[1],
+ v_t[2],
+ v_t[3],
+ wt[0],
+ wt[1],
+ wt[2],
+ wt[3]);
+
+ return simple_read_from_buffer(user_buf, count, ppos,
+ buf, len);
+}
+
+static const struct file_operations airtime_ops = {
+ .read = airtime_read,
+ .open = simple_open,
+ .llseek = default_llseek,
+};
+
#ifdef CONFIG_PM
static ssize_t reset_write(struct file *file, const char __user *user_buf,
size_t count, loff_t *ppos)
@@ -386,8 +426,12 @@ void debugfs_hw_add(struct ieee80211_local *local)
if (local->ops->wake_tx_queue)
DEBUGFS_ADD_MODE(aqm, 0600);
- debugfs_create_u16("airtime_flags", 0600,
- phyd, &local->airtime_flags);
+ if (wiphy_ext_feature_isset(local->hw.wiphy,
+ NL80211_EXT_FEATURE_AIRTIME_FAIRNESS)) {
+ DEBUGFS_ADD_MODE(airtime, 0600);
+ debugfs_create_u16("airtime_flags", 0600,
+ phyd, &local->airtime_flags);
+ }
statsd = debugfs_create_dir("statistics", phyd);
diff --git a/net/mac80211/debugfs_sta.c b/net/mac80211/debugfs_sta.c
index 3aa618d..80028da 100644
--- a/net/mac80211/debugfs_sta.c
+++ b/net/mac80211/debugfs_sta.c
@@ -203,7 +203,7 @@ static ssize_t sta_airtime_read(struct file *file, char __user *userbuf,
size_t bufsz = 200;
char *buf = kzalloc(bufsz, GFP_KERNEL), *p = buf;
u64 rx_airtime = 0, tx_airtime = 0;
- s64 deficit[IEEE80211_NUM_ACS];
+ u64 v_t[IEEE80211_NUM_ACS];
ssize_t rv;
int ac;
@@ -214,20 +214,20 @@ static ssize_t sta_airtime_read(struct file *file, char __user *userbuf,
spin_lock_bh(&local->active_txq_lock[ac]);
rx_airtime += sta->airtime[ac].rx_airtime;
tx_airtime += sta->airtime[ac].tx_airtime;
- deficit[ac] = sta->airtime[ac].deficit;
+ v_t[ac] = sta->airtime[ac].v_t;
spin_unlock_bh(&local->active_txq_lock[ac]);
}
p += scnprintf(p, bufsz + buf - p,
"RX: %llu us\nTX: %llu us\nWeight: %u\n"
- "Deficit: VO: %lld us VI: %lld us BE: %lld us BK: %lld us\n",
+ "Virt-T: VO: %lld us VI: %lld us BE: %lld us BK: %lld us\n",
rx_airtime,
tx_airtime,
sta->airtime_weight,
- deficit[0],
- deficit[1],
- deficit[2],
- deficit[3]);
+ v_t[0],
+ v_t[1],
+ v_t[2],
+ v_t[3]);
rv = simple_read_from_buffer(userbuf, count, ppos, buf, p - buf);
kfree(buf);
@@ -245,7 +245,7 @@ static ssize_t sta_airtime_write(struct file *file, const char __user *userbuf,
spin_lock_bh(&local->active_txq_lock[ac]);
sta->airtime[ac].rx_airtime = 0;
sta->airtime[ac].tx_airtime = 0;
- sta->airtime[ac].deficit = sta->airtime_weight;
+ sta->airtime[ac].v_t = 0;
spin_unlock_bh(&local->active_txq_lock[ac]);
}
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index e170f98..a4556f9 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -846,8 +846,7 @@ struct txq_info {
struct codel_vars def_cvars;
struct codel_stats cstats;
struct sk_buff_head frags;
- struct list_head schedule_order;
- u16 schedule_round;
+ struct rb_node schedule_order;
unsigned long flags;
/* keep last! */
@@ -1141,8 +1140,10 @@ struct ieee80211_local {
/* protects active_txqs and txqi->schedule_order */
spinlock_t active_txq_lock[IEEE80211_NUM_ACS];
- struct list_head active_txqs[IEEE80211_NUM_ACS];
- u16 schedule_round[IEEE80211_NUM_ACS];
+ struct rb_root_cached active_txqs[IEEE80211_NUM_ACS];
+ struct rb_node *schedule_pos[IEEE80211_NUM_ACS];
+ u64 airtime_v_t[IEEE80211_NUM_ACS];
+ u64 airtime_weight_sum[IEEE80211_NUM_ACS];
u16 airtime_flags;
@@ -1779,6 +1780,11 @@ int ieee80211_tx_control_port(struct wiphy *wiphy, struct net_device *dev,
const u8 *buf, size_t len,
const u8 *dest, __be16 proto, bool unencrypted);
+void ieee80211_resort_txq(struct ieee80211_hw *hw,
+ struct ieee80211_txq *txq);
+void ieee80211_unschedule_txq(struct ieee80211_hw *hw,
+ struct ieee80211_txq *txq);
+
/* HT */
void ieee80211_apply_htcap_overrides(struct ieee80211_sub_if_data *sdata,
struct ieee80211_sta_ht_cap *ht_cap);
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 5055aeb..e9ffa8e 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -666,7 +666,7 @@ struct ieee80211_hw *ieee80211_alloc_hw_nm(size_t priv_data_len,
spin_lock_init(&local->queue_stop_reason_lock);
for (i = 0; i < IEEE80211_NUM_ACS; i++) {
- INIT_LIST_HEAD(&local->active_txqs[i]);
+ local->active_txqs[i] = RB_ROOT_CACHED;
spin_lock_init(&local->active_txq_lock[i]);
}
local->airtime_flags = AIRTIME_USE_TX | AIRTIME_USE_RX;
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 11f0589..9d01fdd 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -389,7 +389,6 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
for (i = 0; i < IEEE80211_NUM_ACS; i++) {
skb_queue_head_init(&sta->ps_tx_buf[i]);
skb_queue_head_init(&sta->tx_filtered[i]);
- sta->airtime[i].deficit = sta->airtime_weight;
}
for (i = 0; i < IEEE80211_NUM_TIDS; i++)
@@ -1831,18 +1830,32 @@ void ieee80211_sta_register_airtime(struct ieee80211_sta *pubsta, u8 tid,
{
struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
struct ieee80211_local *local = sta->sdata->local;
+ struct ieee80211_txq *txq = sta->sta.txq[tid];
u8 ac = ieee80211_ac_from_tid(tid);
- u32 airtime = 0;
+ u64 airtime = 0, weight_sum;
+
+ if (!txq)
+ return;
if (sta->local->airtime_flags & AIRTIME_USE_TX)
airtime += tx_airtime;
if (sta->local->airtime_flags & AIRTIME_USE_RX)
airtime += rx_airtime;
+ /* Weights scale so the unit weight is 256 */
+ airtime <<= 8;
+
spin_lock_bh(&local->active_txq_lock[ac]);
+
sta->airtime[ac].tx_airtime += tx_airtime;
sta->airtime[ac].rx_airtime += rx_airtime;
- sta->airtime[ac].deficit -= airtime;
+
+ weight_sum = local->airtime_weight_sum[ac] ?: sta->airtime_weight;
+
+ local->airtime_v_t[ac] += airtime / weight_sum;
+ sta->airtime[ac].v_t += airtime / sta->airtime_weight;
+ ieee80211_resort_txq(&local->hw, txq);
+
spin_unlock_bh(&local->active_txq_lock[ac]);
}
EXPORT_SYMBOL(ieee80211_sta_register_airtime);
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 71f7e49..5c1cac9 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -130,11 +130,12 @@ enum ieee80211_agg_stop_reason {
/* Debugfs flags to enable/disable use of RX/TX airtime in scheduler */
#define AIRTIME_USE_TX BIT(0)
#define AIRTIME_USE_RX BIT(1)
+#define AIRTIME_GRACE 500 /* usec of grace period before reset */
struct airtime_info {
u64 rx_airtime;
u64 tx_airtime;
- s64 deficit;
+ u64 v_t;
};
struct sta_info;
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 61c7ea9..d00baaa 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1449,7 +1449,7 @@ void ieee80211_txq_init(struct ieee80211_sub_if_data *sdata,
codel_vars_init(&txqi->def_cvars);
codel_stats_init(&txqi->cstats);
__skb_queue_head_init(&txqi->frags);
- INIT_LIST_HEAD(&txqi->schedule_order);
+ RB_CLEAR_NODE(&txqi->schedule_order);
txqi->txq.vif = &sdata->vif;
@@ -1493,9 +1493,7 @@ void ieee80211_txq_purge(struct ieee80211_local *local,
ieee80211_purge_tx_queue(&local->hw, &txqi->frags);
spin_unlock_bh(&fq->lock);
- spin_lock_bh(&local->active_txq_lock[txqi->txq.ac]);
- list_del_init(&txqi->schedule_order);
- spin_unlock_bh(&local->active_txq_lock[txqi->txq.ac]);
+ ieee80211_unschedule_txq(&local->hw, &txqi->txq);
}
void ieee80211_txq_set_params(struct ieee80211_local *local)
@@ -3640,126 +3638,191 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
struct ieee80211_txq *ieee80211_next_txq(struct ieee80211_hw *hw, u8 ac)
{
struct ieee80211_local *local = hw_to_local(hw);
+ struct rb_node *node = local->schedule_pos[ac];
struct txq_info *txqi = NULL;
+ bool first = false;
lockdep_assert_held(&local->active_txq_lock[ac]);
- begin:
- txqi = list_first_entry_or_null(&local->active_txqs[ac],
- struct txq_info,
- schedule_order);
- if (!txqi)
+ if (!node) {
+ node = rb_first_cached(&local->active_txqs[ac]);
+ first = true;
+ } else {
+ node = rb_next(node);
+ }
+
+ if (!node)
return NULL;
+ txqi = container_of(node, struct txq_info, schedule_order);
+
if (txqi->txq.sta) {
struct sta_info *sta = container_of(txqi->txq.sta,
struct sta_info, sta);
- if (sta->airtime[txqi->txq.ac].deficit < 0) {
- sta->airtime[txqi->txq.ac].deficit +=
- sta->airtime_weight;
- list_move_tail(&txqi->schedule_order,
- &local->active_txqs[txqi->txq.ac]);
- goto begin;
+ if (sta->airtime[ac].v_t > local->airtime_v_t[ac]) {
+ if (first)
+ local->airtime_v_t[ac] = sta->airtime[ac].v_t;
+ else
+ return NULL;
}
}
- if (txqi->schedule_round == local->schedule_round[ac])
- return NULL;
-
- list_del_init(&txqi->schedule_order);
- txqi->schedule_round = local->schedule_round[ac];
+ local->schedule_pos[ac] = node;
return &txqi->txq;
}
EXPORT_SYMBOL(ieee80211_next_txq);
-void ieee80211_return_txq(struct ieee80211_hw *hw,
+static void __ieee80211_insert_txq(struct rb_root_cached *root,
+ struct txq_info *txqi, u8 ac)
+{
+ struct rb_node **new = &root->rb_root.rb_node;
+ struct rb_node *parent = NULL;
+ struct txq_info *__txqi;
+ bool leftmost = true;
+
+ while (*new) {
+ parent = *new;
+ __txqi = rb_entry(parent, struct txq_info, schedule_order);
+
+ if (!txqi->txq.sta) {
+ /* new txqi has no sta - insert to the left */
+ new = &parent->rb_left;
+ } else if (!__txqi->txq.sta) {
+ /* existing txqi has no sta - insert to the right */
+ new = &parent->rb_right;
+ leftmost = false;
+ } else {
+ struct sta_info *old_sta = container_of(__txqi->txq.sta,
+ struct sta_info,
+ sta);
+ struct sta_info *new_sta = container_of(txqi->txq.sta,
+ struct sta_info,
+ sta);
+
+ if (new_sta->airtime[ac].v_t <= old_sta->airtime[ac].v_t) {
+ new = &parent->rb_left;
+ } else {
+ new = &parent->rb_right;
+ leftmost = false;
+ }
+ }
+ }
+
+ rb_link_node(&txqi->schedule_order, parent, new);
+ rb_insert_color_cached(&txqi->schedule_order, root, leftmost);
+}
+
+void ieee80211_schedule_txq(struct ieee80211_hw *hw,
+ struct ieee80211_txq *txq)
+ __acquires(txq_lock) __releases(txq_lock)
+{
+ struct ieee80211_local *local = hw_to_local(hw);
+ struct txq_info *txqi = to_txq_info(txq);
+ u8 ac = txq->ac;
+
+ spin_lock_bh(&local->active_txq_lock[ac]);
+
+ if (!RB_EMPTY_NODE(&txqi->schedule_order))
+ goto out;
+
+ if (txq->sta) {
+ struct sta_info *sta = container_of(txq->sta,
+ struct sta_info, sta);
+
+ local->airtime_weight_sum[ac] += sta->airtime_weight;
+ if (local->airtime_v_t[ac] > AIRTIME_GRACE)
+ sta->airtime[ac].v_t = max(local->airtime_v_t[ac] - AIRTIME_GRACE,
+ sta->airtime[ac].v_t);
+ }
+
+ __ieee80211_insert_txq(&local->active_txqs[ac], txqi, ac);
+
+ out:
+ spin_unlock_bh(&local->active_txq_lock[ac]);
+}
+EXPORT_SYMBOL(ieee80211_schedule_txq);
+
+void ieee80211_resort_txq(struct ieee80211_hw *hw,
struct ieee80211_txq *txq)
{
struct ieee80211_local *local = hw_to_local(hw);
struct txq_info *txqi = to_txq_info(txq);
+ u8 ac = txq->ac;
+
+ if (!RB_EMPTY_NODE(&txqi->schedule_order)) {
+ rb_erase_cached(&txqi->schedule_order,
+ &local->active_txqs[ac]);
+ RB_CLEAR_NODE(&txqi->schedule_order);
+ __ieee80211_insert_txq(&local->active_txqs[ac], txqi, ac);
+ }
+}
+
+static void __ieee80211_unschedule_txq(struct ieee80211_hw *hw,
+ struct ieee80211_txq *txq)
+{
+ struct ieee80211_local *local = hw_to_local(hw);
+ struct txq_info *txqi = to_txq_info(txq);
+ u8 ac = txq->ac;
lockdep_assert_held(&local->active_txq_lock[txq->ac]);
- if (list_empty(&txqi->schedule_order) &&
- (!skb_queue_empty(&txqi->frags) || txqi->tin.backlog_packets)) {
- /* If airtime accounting is active, always enqueue STAs at the
- * head of the list to ensure that they only get moved to the
- * back by the airtime DRR scheduler once they have a negative
- * deficit. A station that already has a negative deficit will
- * get immediately moved to the back of the list on the next
- * call to ieee80211_next_txq().
- */
- if (txqi->txq.sta &&
- wiphy_ext_feature_isset(local->hw.wiphy,
- NL80211_EXT_FEATURE_AIRTIME_FAIRNESS))
- list_add(&txqi->schedule_order,
- &local->active_txqs[txq->ac]);
- else
- list_add_tail(&txqi->schedule_order,
- &local->active_txqs[txq->ac]);
+ if (RB_EMPTY_NODE(&txqi->schedule_order))
+ return;
+
+ if (txq->sta) {
+ struct sta_info *sta = container_of(txq->sta,
+ struct sta_info, sta);
+
+ local->airtime_weight_sum[ac] -= sta->airtime_weight;
}
+
+ rb_erase_cached(&txqi->schedule_order,
+ &local->active_txqs[txq->ac]);
+ RB_CLEAR_NODE(&txqi->schedule_order);
}
-EXPORT_SYMBOL(ieee80211_return_txq);
-void ieee80211_schedule_txq(struct ieee80211_hw *hw,
- struct ieee80211_txq *txq)
+void ieee80211_unschedule_txq(struct ieee80211_hw *hw,
+ struct ieee80211_txq *txq)
__acquires(txq_lock) __releases(txq_lock)
{
struct ieee80211_local *local = hw_to_local(hw);
spin_lock_bh(&local->active_txq_lock[txq->ac]);
- ieee80211_return_txq(hw, txq);
+ __ieee80211_unschedule_txq(hw, txq);
spin_unlock_bh(&local->active_txq_lock[txq->ac]);
}
-EXPORT_SYMBOL(ieee80211_schedule_txq);
+
+void ieee80211_return_txq(struct ieee80211_hw *hw,
+ struct ieee80211_txq *txq)
+{
+ struct ieee80211_local *local = hw_to_local(hw);
+ struct txq_info *txqi = to_txq_info(txq);
+
+ lockdep_assert_held(&local->active_txq_lock[txq->ac]);
+
+ if (!RB_EMPTY_NODE(&txqi->schedule_order) &&
+ (skb_queue_empty(&txqi->frags) && !txqi->tin.backlog_packets))
+ __ieee80211_unschedule_txq(hw, txq);
+}
+EXPORT_SYMBOL(ieee80211_return_txq);
bool ieee80211_txq_may_transmit(struct ieee80211_hw *hw,
struct ieee80211_txq *txq)
{
struct ieee80211_local *local = hw_to_local(hw);
- struct txq_info *iter, *tmp, *txqi = to_txq_info(txq);
+ struct txq_info *txqi = to_txq_info(txq);
struct sta_info *sta;
u8 ac = txq->ac;
lockdep_assert_held(&local->active_txq_lock[ac]);
if (!txqi->txq.sta)
- goto out;
-
- if (list_empty(&txqi->schedule_order))
- goto out;
-
- list_for_each_entry_safe(iter, tmp, &local->active_txqs[ac],
- schedule_order) {
- if (iter == txqi)
- break;
-
- if (!iter->txq.sta) {
- list_move_tail(&iter->schedule_order,
- &local->active_txqs[ac]);
- continue;
- }
- sta = container_of(iter->txq.sta, struct sta_info, sta);
- if (sta->airtime[ac].deficit < 0)
- sta->airtime[ac].deficit += sta->airtime_weight;
- list_move_tail(&iter->schedule_order, &local->active_txqs[ac]);
- }
+ return true;
sta = container_of(txqi->txq.sta, struct sta_info, sta);
- if (sta->airtime[ac].deficit >= 0)
- goto out;
-
- sta->airtime[ac].deficit += sta->airtime_weight;
- list_move_tail(&txqi->schedule_order, &local->active_txqs[ac]);
-
- return false;
-out:
- if (!list_empty(&txqi->schedule_order))
- list_del_init(&txqi->schedule_order);
-
- return true;
+ return (sta->airtime[ac].v_t <= local->airtime_v_t[ac]);
}
EXPORT_SYMBOL(ieee80211_txq_may_transmit);
@@ -3769,7 +3832,6 @@ void ieee80211_txq_schedule_start(struct ieee80211_hw *hw, u8 ac)
struct ieee80211_local *local = hw_to_local(hw);
spin_lock_bh(&local->active_txq_lock[ac]);
- local->schedule_round[ac]++;
}
EXPORT_SYMBOL(ieee80211_txq_schedule_start);
@@ -3778,6 +3840,7 @@ void ieee80211_txq_schedule_end(struct ieee80211_hw *hw, u8 ac)
{
struct ieee80211_local *local = hw_to_local(hw);
+ local->schedule_pos[ac] = NULL;
spin_unlock_bh(&local->active_txq_lock[ac]);
}
EXPORT_SYMBOL(ieee80211_txq_schedule_end);
--
1.9.1
Global airtime weight sum is updated only when txq is added/removed
from rbtree. If upper layer configures sta weight during high load,
airtime weight sum will not be updated since txq is most likely on the
tree. It could a little late for upper layer to reconfigure sta weight
when txq is already in the rbtree. And thus, incorrect airtime weight sum
will lead to incorrect global virtual time calculation as well as global
airtime weight sum overflow of airtime weight sum during txq removed.
Hence, need to update airtime weight sum upon receiving event for
configuring sta weight once sta's txq is on the rbtree.
Besides, if airtime weight sum of ACs and sta weight is synced under the
same per AC lock protection, there can be a very short window causing
incorrct airtime weight sum calculation as below:
active_txq_lock_VO .
VO weight sum is syncd .
sta airtime weight sum is synced .
active_txq_unlock_VO .
. .
active_txq_lock_VI .
VI weight sum is syncd .
sta airtime weight sum active_txq_lock_BE
active_txq_unlock_VI Remove txq and thus sum
. is calculated with synced
. sta airtime weight
. active_txq_unlock_BE
So introduce a per ac synced station airtime weight synced with per
AC synced weight sum together. And the per-AC station airtime weight
is used to calculate weight sum.
Signed-off-by: Yibo Zhao <[email protected]>
---
net/mac80211/cfg.c | 27 +++++++++++++++++++++++++--
net/mac80211/sta_info.c | 6 ++++--
net/mac80211/sta_info.h | 3 +++
net/mac80211/tx.c | 4 ++--
4 files changed, 34 insertions(+), 6 deletions(-)
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index d65aa01..4b420bb 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1284,7 +1284,8 @@ static int sta_apply_parameters(struct ieee80211_local *local,
int ret = 0;
struct ieee80211_supported_band *sband;
struct ieee80211_sub_if_data *sdata = sta->sdata;
- u32 mask, set;
+ u32 mask, set, tid, ac;
+ struct txq_info *txqi;
sband = ieee80211_get_sband(sdata);
if (!sband)
@@ -1452,8 +1453,30 @@ static int sta_apply_parameters(struct ieee80211_local *local,
if (ieee80211_vif_is_mesh(&sdata->vif))
sta_apply_mesh_params(local, sta, params);
- if (params->airtime_weight)
+ if (params->airtime_weight &&
+ params->airtime_weight != sta->airtime_weight) {
+ for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
+ spin_lock_bh(&local->active_txq_lock[ac]);
+ for (tid = 0; tid < IEEE80211_NUM_TIDS + 1; tid++) {
+ if (!sta->sta.txq[tid] ||
+ ac != ieee80211_ac_from_tid(tid))
+ continue;
+
+ sta->airtime_weight_synced[ac] =
+ params->airtime_weight;
+
+ txqi = to_txq_info(sta->sta.txq[tid]);
+ if (RB_EMPTY_NODE(&txqi->schedule_order))
+ continue;
+
+ local->airtime_weight_sum[ac] = local->airtime_weight_sum[ac] +
+ params->airtime_weight -
+ sta->airtime_weight;
+ }
+ spin_unlock_bh(&local->active_txq_lock[ac]);
+ }
sta->airtime_weight = params->airtime_weight;
+ }
/* set the STA state after all sta info from usermode has been set */
if (test_sta_flag(sta, WLAN_STA_TDLS_PEER) ||
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index feac975..b00812f 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -389,6 +389,7 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
for (i = 0; i < IEEE80211_NUM_ACS; i++) {
skb_queue_head_init(&sta->ps_tx_buf[i]);
skb_queue_head_init(&sta->tx_filtered[i]);
+ sta->airtime_weight_synced[i] = sta->airtime_weight;
}
for (i = 0; i < IEEE80211_NUM_TIDS; i++)
@@ -1850,11 +1851,12 @@ void ieee80211_sta_register_airtime(struct ieee80211_sta *pubsta, u8 tid,
sta->airtime[ac].tx_airtime += tx_airtime;
sta->airtime[ac].rx_airtime += rx_airtime;
- weight_sum = local->airtime_weight_sum[ac] ?: sta->airtime_weight;
+ weight_sum = local->airtime_weight_sum[ac] ?
+ : sta->airtime_weight_synced[ac];
/* Round the calculation of global vt */
local->airtime_v_t[ac] += (airtime + (weight_sum >> 1)) / weight_sum;
- sta->airtime[ac].v_t += airtime / sta->airtime_weight;
+ sta->airtime[ac].v_t += airtime / sta->airtime_weight_synced[ac];
ieee80211_resort_txq(&local->hw, txq);
spin_unlock_bh(&local->active_txq_lock[ac]);
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 5055f94..1298902 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -476,6 +476,8 @@ struct ieee80211_sta_rx_stats {
* @tid_seq: per-TID sequence numbers for sending to this STA
* @airtime: per-AC struct airtime_info describing airtime statistics for this
* station
+ * @airtime_weight_synced: station per-AC airtime weight for sync and
+ * calculation
* @airtime_weight: station weight for airtime fairness calculation purposes
* @ampdu_mlme: A-MPDU state machine state
* @mesh: mesh STA information
@@ -602,6 +604,7 @@ struct sta_info {
u16 tid_seq[IEEE80211_QOS_CTL_TID_MASK + 1];
struct airtime_info airtime[IEEE80211_NUM_ACS];
+ u16 airtime_weight_synced[IEEE80211_NUM_ACS];
u16 airtime_weight;
/*
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 60cf569..3592d49 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -3735,7 +3735,7 @@ void ieee80211_schedule_txq(struct ieee80211_hw *hw,
struct sta_info *sta = container_of(txq->sta,
struct sta_info, sta);
- local->airtime_weight_sum[ac] += sta->airtime_weight;
+ local->airtime_weight_sum[ac] += sta->airtime_weight_synced[ac];
if (local->airtime_v_t[ac] > AIRTIME_GRACE)
sta->airtime[ac].v_t = max(local->airtime_v_t[ac] - AIRTIME_GRACE,
sta->airtime[ac].v_t);
@@ -3779,7 +3779,7 @@ static void __ieee80211_unschedule_txq(struct ieee80211_hw *hw,
struct sta_info *sta = container_of(txq->sta,
struct sta_info, sta);
- local->airtime_weight_sum[ac] -= sta->airtime_weight;
+ local->airtime_weight_sum[ac] -= sta->airtime_weight_synced[ac];
}
rb_erase_cached(&txqi->schedule_order,
--
1.9.1
Yibo Zhao <[email protected]> writes:
> From: Toke Høiland-Jørgensen <[email protected]>
>
> This switches the airtime scheduler in mac80211 to use a virtual time-based
> scheduler instead of the round-robin scheduler used before. This has a
> couple of advantages:
Thank you for keeping at this! I'll take a look at the series in detail
tomorrow.
While you're testing things related to this, I've also prototyped a port
of the "airtime queue limit" feature from chromeos into mainline. It's
currently in my tree here:
https://git.kernel.org/pub/scm/linux/kernel/git/toke/linux.git/log/?h=mac80211-aql-01
If you have time to test it at some point, that would be awesome. I'm
planning to submit it as an RFC, but it needs a bit more work first.
Also, it's completely untested, but it does compile :)
-Toke
Yibo Zhao <[email protected]> writes:
> Global airtime weight sum is updated only when txq is added/removed
> from rbtree. If upper layer configures sta weight during high load,
> airtime weight sum will not be updated since txq is most likely on the
> tree. It could a little late for upper layer to reconfigure sta weight
> when txq is already in the rbtree. And thus, incorrect airtime weight sum
> will lead to incorrect global virtual time calculation as well as global
> airtime weight sum overflow of airtime weight sum during txq removed.
>
> Hence, need to update airtime weight sum upon receiving event for
> configuring sta weight once sta's txq is on the rbtree.
>
> Besides, if airtime weight sum of ACs and sta weight is synced under the
> same per AC lock protection, there can be a very short window causing
> incorrct airtime weight sum calculation as below:
>
> active_txq_lock_VO .
> VO weight sum is syncd .
> sta airtime weight sum is synced .
> active_txq_unlock_VO .
> . .
> active_txq_lock_VI .
> VI weight sum is syncd .
> sta airtime weight sum active_txq_lock_BE
> active_txq_unlock_VI Remove txq and thus sum
> . is calculated with synced
> . sta airtime weight
> . active_txq_unlock_BE
>
> So introduce a per ac synced station airtime weight synced with per
> AC synced weight sum together. And the per-AC station airtime weight
> is used to calculate weight sum.
>
> Signed-off-by: Yibo Zhao <[email protected]>
> ---
> net/mac80211/cfg.c | 27 +++++++++++++++++++++++++--
> net/mac80211/sta_info.c | 6 ++++--
> net/mac80211/sta_info.h | 3 +++
> net/mac80211/tx.c | 4 ++--
> 4 files changed, 34 insertions(+), 6 deletions(-)
>
> diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
> index d65aa01..4b420bb 100644
> --- a/net/mac80211/cfg.c
> +++ b/net/mac80211/cfg.c
> @@ -1284,7 +1284,8 @@ static int sta_apply_parameters(struct ieee80211_local *local,
> int ret = 0;
> struct ieee80211_supported_band *sband;
> struct ieee80211_sub_if_data *sdata = sta->sdata;
> - u32 mask, set;
> + u32 mask, set, tid, ac;
> + struct txq_info *txqi;
>
> sband = ieee80211_get_sband(sdata);
> if (!sband)
> @@ -1452,8 +1453,30 @@ static int sta_apply_parameters(struct ieee80211_local *local,
> if (ieee80211_vif_is_mesh(&sdata->vif))
> sta_apply_mesh_params(local, sta, params);
>
> - if (params->airtime_weight)
> + if (params->airtime_weight &&
> + params->airtime_weight != sta->airtime_weight) {
> + for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
> + spin_lock_bh(&local->active_txq_lock[ac]);
> + for (tid = 0; tid < IEEE80211_NUM_TIDS + 1; tid++) {
> + if (!sta->sta.txq[tid] ||
> + ac != ieee80211_ac_from_tid(tid))
> + continue;
> +
> + sta->airtime_weight_synced[ac] =
> + params->airtime_weight;
> +
> + txqi = to_txq_info(sta->sta.txq[tid]);
> + if (RB_EMPTY_NODE(&txqi->schedule_order))
> + continue;
> +
> + local->airtime_weight_sum[ac] = local->airtime_weight_sum[ac] +
> + params->airtime_weight -
> + sta->airtime_weight;
> + }
> + spin_unlock_bh(&local->active_txq_lock[ac]);
> + }
> sta->airtime_weight = params->airtime_weight;
With this, airtime_weight is basically only used to return to and from
userspace, right? I.e., after the above loop has run, it will match the
contents of airtime_weight_synced; so why not just turn airtime_weight
into a per-ac array? You could just use airtime_weight[0] as the value
to return to userspace...
-Toke
Yibo Zhao <[email protected]> writes:
> From: Toke Høiland-Jørgensen <[email protected]>
>
> This switches the airtime scheduler in mac80211 to use a virtual time-based
> scheduler instead of the round-robin scheduler used before. This has a
> couple of advantages:
>
> - No need to sync up the round-robin scheduler in firmware/hardware with
> the round-robin airtime scheduler.
>
> - If several stations are eligible for transmission we can schedule both of
> them; no need to hard-block the scheduling rotation until the head of the
> queue has used up its quantum.
>
> - The check of whether a station is eligible for transmission becomes
> simpler (in ieee80211_txq_may_transmit()).
>
> The drawback is that scheduling becomes slightly more expensive, as we need
> to maintain an rbtree of TXQs sorted by virtual time. This means that
> ieee80211_register_airtime() becomes O(logN) in the number of currently
> scheduled TXQs. However, hopefully this number rarely grows too big (it's
> only TXQs currently backlogged, not all associated stations), so it
> shouldn't be too big of an issue.
>
> Signed-off-by: Toke Høiland-Jørgensen <[email protected]>
I'll note that this patch still has the two issues that Felix pointed
out when I posted the RFC version. Namely:
- The use of divisions in the fast path. I guess I need to go write some
reciprocal-calculation code, since that is also an issue with the AQL
patches I linked to before.
- The fact that we don't count the airtime usage of multicast traffic,
which with this series means that the vif TXQ will get priority over
the others. I think we agreed to fix this by just adding an airtime
v_t to the vif as well and use that for scheduling the TXQ. Does
ath10k report airtime usage for multicast as well, or only for
stations?
-Toke
On 2019-09-18 05:24, Toke Høiland-Jørgensen wrote:
> Yibo Zhao <[email protected]> writes:
>
>> Global airtime weight sum is updated only when txq is added/removed
>> from rbtree. If upper layer configures sta weight during high load,
>> airtime weight sum will not be updated since txq is most likely on the
>> tree. It could a little late for upper layer to reconfigure sta weight
>> when txq is already in the rbtree. And thus, incorrect airtime weight
>> sum
>> will lead to incorrect global virtual time calculation as well as
>> global
>> airtime weight sum overflow of airtime weight sum during txq removed.
>>
>> Hence, need to update airtime weight sum upon receiving event for
>> configuring sta weight once sta's txq is on the rbtree.
>>
>> Besides, if airtime weight sum of ACs and sta weight is synced under
>> the
>> same per AC lock protection, there can be a very short window causing
>> incorrct airtime weight sum calculation as below:
>>
>> active_txq_lock_VO .
>> VO weight sum is syncd .
>> sta airtime weight sum is synced .
>> active_txq_unlock_VO .
>> . .
>> active_txq_lock_VI .
>> VI weight sum is syncd .
>> sta airtime weight sum active_txq_lock_BE
>> active_txq_unlock_VI Remove txq and thus sum
>> . is calculated with synced
>> . sta airtime weight
>> . active_txq_unlock_BE
>>
>> So introduce a per ac synced station airtime weight synced with per
>> AC synced weight sum together. And the per-AC station airtime weight
>> is used to calculate weight sum.
>>
>> Signed-off-by: Yibo Zhao <[email protected]>
>> ---
>> net/mac80211/cfg.c | 27 +++++++++++++++++++++++++--
>> net/mac80211/sta_info.c | 6 ++++--
>> net/mac80211/sta_info.h | 3 +++
>> net/mac80211/tx.c | 4 ++--
>> 4 files changed, 34 insertions(+), 6 deletions(-)
>>
>> diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
>> index d65aa01..4b420bb 100644
>> --- a/net/mac80211/cfg.c
>> +++ b/net/mac80211/cfg.c
>> @@ -1284,7 +1284,8 @@ static int sta_apply_parameters(struct
>> ieee80211_local *local,
>> int ret = 0;
>> struct ieee80211_supported_band *sband;
>> struct ieee80211_sub_if_data *sdata = sta->sdata;
>> - u32 mask, set;
>> + u32 mask, set, tid, ac;
>> + struct txq_info *txqi;
>>
>> sband = ieee80211_get_sband(sdata);
>> if (!sband)
>> @@ -1452,8 +1453,30 @@ static int sta_apply_parameters(struct
>> ieee80211_local *local,
>> if (ieee80211_vif_is_mesh(&sdata->vif))
>> sta_apply_mesh_params(local, sta, params);
>>
>> - if (params->airtime_weight)
>> + if (params->airtime_weight &&
>> + params->airtime_weight != sta->airtime_weight) {
>> + for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
>> + spin_lock_bh(&local->active_txq_lock[ac]);
>> + for (tid = 0; tid < IEEE80211_NUM_TIDS + 1; tid++) {
>> + if (!sta->sta.txq[tid] ||
>> + ac != ieee80211_ac_from_tid(tid))
>> + continue;
>> +
>> + sta->airtime_weight_synced[ac] =
>> + params->airtime_weight;
>> +
>> + txqi = to_txq_info(sta->sta.txq[tid]);
>> + if (RB_EMPTY_NODE(&txqi->schedule_order))
>> + continue;
>> +
>> + local->airtime_weight_sum[ac] = local->airtime_weight_sum[ac] +
>> + params->airtime_weight -
>> + sta->airtime_weight;
>> + }
>> + spin_unlock_bh(&local->active_txq_lock[ac]);
>> + }
>> sta->airtime_weight = params->airtime_weight;
>
> With this, airtime_weight is basically only used to return to and from
> userspace, right? I.e., after the above loop has run, it will match the
> contents of airtime_weight_synced; so why not just turn airtime_weight
> into a per-ac array? You could just use airtime_weight[0] as the value
> to return to userspace...
Yes, I also feel it is a little weird to keep both of them. I am fine
with suggestion.
>
> -Toke
--
Yibo
On 2019-09-18 05:31, Toke Høiland-Jørgensen wrote:
> Yibo Zhao <[email protected]> writes:
>
>> From: Toke Høiland-Jørgensen <[email protected]>
>>
>> This switches the airtime scheduler in mac80211 to use a virtual
>> time-based
>> scheduler instead of the round-robin scheduler used before. This has a
>> couple of advantages:
>>
>> - No need to sync up the round-robin scheduler in firmware/hardware
>> with
>> the round-robin airtime scheduler.
>>
>> - If several stations are eligible for transmission we can schedule
>> both of
>> them; no need to hard-block the scheduling rotation until the head
>> of the
>> queue has used up its quantum.
>>
>> - The check of whether a station is eligible for transmission becomes
>> simpler (in ieee80211_txq_may_transmit()).
>>
>> The drawback is that scheduling becomes slightly more expensive, as we
>> need
>> to maintain an rbtree of TXQs sorted by virtual time. This means that
>> ieee80211_register_airtime() becomes O(logN) in the number of
>> currently
>> scheduled TXQs. However, hopefully this number rarely grows too big
>> (it's
>> only TXQs currently backlogged, not all associated stations), so it
>> shouldn't be too big of an issue.
>>
>> Signed-off-by: Toke Høiland-Jørgensen <[email protected]>
>
> I'll note that this patch still has the two issues that Felix pointed
> out when I posted the RFC version. Namely:
>
> - The use of divisions in the fast path. I guess I need to go write
> some
> reciprocal-calculation code, since that is also an issue with the AQL
> patches I linked to before.
>
> - The fact that we don't count the airtime usage of multicast traffic,
> which with this series means that the vif TXQ will get priority over
> the others. I think we agreed to fix this by just adding an airtime
> v_t to the vif as well and use that for scheduling the TXQ. Does
> ath10k report airtime usage for multicast as well, or only for
> stations?
>
>
I remember we have Felix' patches reducing the time the lock is held in
mac80211 for DRR, do we need to integrate it into this version？
> -Toke
--
Yibo