Commit b4809e94 authored by Toke Høiland-Jørgensen's avatar Toke Høiland-Jørgensen Committed by Johannes Berg
Browse files

mac80211: Add airtime accounting and scheduling to TXQs 



This adds airtime accounting and scheduling to the mac80211 TXQ
scheduler. A new callback, ieee80211_sta_register_airtime(), is added
that drivers can call to report airtime usage for stations.

When airtime information is present, mac80211 will schedule TXQs
(through ieee80211_next_txq()) in a way that enforces airtime fairness
between active stations. This scheduling works the same way as the ath9k
in-driver airtime fairness scheduling. If no airtime usage is reported
by the driver, the scheduler will default to round-robin scheduling.

For drivers that don't control TXQ scheduling in software, a new API
function, ieee80211_txq_may_transmit(), is added which the driver can use
to check if the TXQ is eligible for transmission, or should be throttled to
enforce fairness. Calls to this function must also be enclosed in
ieee80211_txq_schedule_{start,end}() calls to ensure proper locking.

The API ieee80211_txq_may_transmit() also ensures that TXQ list will be
aligned aginst driver's own round-robin scheduler list. i.e it rotates
the TXQ list till it makes the requested node becomes the first entry
in TXQ list. Thus both the TXQ list and driver's list are in sync.

Co-developed-by: default avatarRajkumar Manoharan <rmanohar@codeaurora.org>
Signed-off-by: default avatarLouie Lu <git@louie.lu>
[added debugfs write op to reset airtime counter]
Signed-off-by: default avatarToke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: default avatarRajkumar Manoharan <rmanohar@codeaurora.org>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 36647055

include/net/mac80211.h

+59 −0
Original line number Original line Diff line number Diff line
@@ -2360,6 +2360,9 @@ enum ieee80211_hw_flags { 
 * @tx_sk_pacing_shift: Pacing shift to set on TCP sockets when frames from

 * @tx_sk_pacing_shift: Pacing shift to set on TCP sockets when frames from

 *	them are encountered. The default should typically not be changed,

 *	them are encountered. The default should typically not be changed,

 *	unless the driver has good reasons for needing more buffers.

 *	unless the driver has good reasons for needing more buffers.

 *

 * @weight_multipler: Driver specific airtime weight multiplier used while

 *	refilling deficit of each TXQ.

 */

 */

struct ieee80211_hw {

struct ieee80211_hw {

	struct ieee80211_conf conf;

	struct ieee80211_conf conf;
@@ -2396,6 +2399,7 @@ struct ieee80211_hw { 
	const struct ieee80211_cipher_scheme *cipher_schemes;

	const struct ieee80211_cipher_scheme *cipher_schemes;

	u8 max_nan_de_entries;

	u8 max_nan_de_entries;

	u8 tx_sk_pacing_shift;

	u8 tx_sk_pacing_shift;

	u8 weight_multiplier;

};

};





static inline bool _ieee80211_hw_check(struct ieee80211_hw *hw,

static inline bool _ieee80211_hw_check(struct ieee80211_hw *hw,
@@ -5407,6 +5411,34 @@ void ieee80211_sta_eosp(struct ieee80211_sta *pubsta); 
 */

 */

void ieee80211_send_eosp_nullfunc(struct ieee80211_sta *pubsta, int tid);

void ieee80211_send_eosp_nullfunc(struct ieee80211_sta *pubsta, int tid);





/**

 * ieee80211_sta_register_airtime - register airtime usage for a sta/tid

 *

 * Register airtime usage for a given sta on a given tid. The driver can call

 * this function to notify mac80211 that a station used a certain amount of

 * airtime. This information will be used by the TXQ scheduler to schedule

 * stations in a way that ensures airtime fairness.

 *

 * The reported airtime should as a minimum include all time that is spent

 * transmitting to the remote station, including overhead and padding, but not

 * including time spent waiting for a TXOP. If the time is not reported by the

 * hardware it can in some cases be calculated from the rate and known frame

 * composition. When possible, the time should include any failed transmission

 * attempts.

 *

 * The driver can either call this function synchronously for every packet or

 * aggregate, or asynchronously as airtime usage information becomes available.

 * TX and RX airtime can be reported together, or separately by setting one of

 * them to 0.

 *

 * @pubsta: the station

 * @tid: the TID to register airtime for

 * @tx_airtime: airtime used during TX (in usec)

 * @rx_airtime: airtime used during RX (in usec)

 */

void ieee80211_sta_register_airtime(struct ieee80211_sta *pubsta, u8 tid,

				    u32 tx_airtime, u32 rx_airtime);



/**

/**

 * ieee80211_iter_keys - iterate keys programmed into the device

 * ieee80211_iter_keys - iterate keys programmed into the device

 * @hw: pointer obtained from ieee80211_alloc_hw()

 * @hw: pointer obtained from ieee80211_alloc_hw()
@@ -6173,6 +6205,33 @@ void ieee80211_txq_schedule_start(struct ieee80211_hw *hw, u8 ac) 
void ieee80211_txq_schedule_end(struct ieee80211_hw *hw, u8 ac)

void ieee80211_txq_schedule_end(struct ieee80211_hw *hw, u8 ac)

	__releases(txq_lock);

	__releases(txq_lock);





/**

 * ieee80211_txq_may_transmit - check whether TXQ is allowed to transmit

 *

 * This function is used to check whether given txq is allowed to transmit by

 * the airtime scheduler, and can be used by drivers to access the airtime

 * fairness accounting without going using the scheduling order enfored by

 * next_txq().

 *

 * Returns %true if the airtime scheduler thinks the TXQ should be allowed to

 * transmit, and %false if it should be throttled. This function can also have

 * the side effect of rotating the TXQ in the scheduler rotation, which will

 * eventually bring the deficit to positive and allow the station to transmit

 * again.

 *

 * The API ieee80211_txq_may_transmit() also ensures that TXQ list will be

 * aligned aginst driver's own round-robin scheduler list. i.e it rotates

 * the TXQ list till it makes the requested node becomes the first entry

 * in TXQ list. Thus both the TXQ list and driver's list are in sync. If this

 * function returns %true, the driver is expected to schedule packets

 * for transmission, and then return the TXQ through ieee80211_return_txq().

 *

 * @hw: pointer as obtained from ieee80211_alloc_hw()

 * @txq: pointer obtained from station or virtual interface

 */

bool ieee80211_txq_may_transmit(struct ieee80211_hw *hw,

				struct ieee80211_txq *txq);



/**

/**

 * ieee80211_txq_get_depth - get pending frame/byte count of given txq

 * ieee80211_txq_get_depth - get pending frame/byte count of given txq

 *

 *

net/mac80211/cfg.c

+3 −0
Original line number Original line Diff line number Diff line
@@ -1447,6 +1447,9 @@ static int sta_apply_parameters(struct ieee80211_local *local, 
	if (ieee80211_vif_is_mesh(&sdata->vif))

	if (ieee80211_vif_is_mesh(&sdata->vif))

		sta_apply_mesh_params(local, sta, params);

		sta_apply_mesh_params(local, sta, params);





	if (params->airtime_weight)

		sta->airtime_weight = params->airtime_weight;



	/* set the STA state after all sta info from usermode has been set */

	/* set the STA state after all sta info from usermode has been set */

	if (test_sta_flag(sta, WLAN_STA_TDLS_PEER) ||

	if (test_sta_flag(sta, WLAN_STA_TDLS_PEER) ||

	    set & BIT(NL80211_STA_FLAG_ASSOCIATED)) {

	    set & BIT(NL80211_STA_FLAG_ASSOCIATED)) {

net/mac80211/debugfs.c

+3 −0
Original line number Original line Diff line number Diff line
@@ -383,6 +383,9 @@ void debugfs_hw_add(struct ieee80211_local *local) 
	if (local->ops->wake_tx_queue)

	if (local->ops->wake_tx_queue)

		DEBUGFS_ADD_MODE(aqm, 0600);

		DEBUGFS_ADD_MODE(aqm, 0600);





	debugfs_create_u16("airtime_flags", 0600,

			   phyd, &local->airtime_flags);



	statsd = debugfs_create_dir("statistics", phyd);

	statsd = debugfs_create_dir("statistics", phyd);





	/* if the dir failed, don't put all the other things into the root! */

	/* if the dir failed, don't put all the other things into the root! */

net/mac80211/debugfs_sta.c

+65 −3
Original line number Original line Diff line number Diff line
@@ -181,9 +181,9 @@ static ssize_t sta_aqm_read(struct file *file, char __user *userbuf, 
			       txqi->tin.tx_bytes,

			       txqi->tin.tx_bytes,

			       txqi->tin.tx_packets,

			       txqi->tin.tx_packets,

			       txqi->flags,

			       txqi->flags,

			       txqi->flags & (1<<IEEE80211_TXQ_STOP) ? "STOP" : "RUN",

			       test_bit(IEEE80211_TXQ_STOP, &txqi->flags) ? "STOP" : "RUN",

			       txqi->flags & (1<<IEEE80211_TXQ_AMPDU) ? " AMPDU" : "",

			       test_bit(IEEE80211_TXQ_AMPDU, &txqi->flags) ? " AMPDU" : "",

			       txqi->flags & (1<<IEEE80211_TXQ_NO_AMSDU) ? " NO-AMSDU" : "");

			       test_bit(IEEE80211_TXQ_NO_AMSDU, &txqi->flags) ? " NO-AMSDU" : "");

	}

	}





	rcu_read_unlock();

	rcu_read_unlock();
@@ -195,6 +195,64 @@ static ssize_t sta_aqm_read(struct file *file, char __user *userbuf, 
}

}

STA_OPS(aqm);

STA_OPS(aqm);





static ssize_t sta_airtime_read(struct file *file, char __user *userbuf,

				size_t count, loff_t *ppos)

{

	struct sta_info *sta = file->private_data;

	struct ieee80211_local *local = sta->sdata->local;

	size_t bufsz = 200;

	char *buf = kzalloc(bufsz, GFP_KERNEL), *p = buf;

	u64 rx_airtime = 0, tx_airtime = 0;

	s64 deficit[IEEE80211_NUM_ACS];

	ssize_t rv;

	int ac;



	if (!buf)

		return -ENOMEM;



	for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {

		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;

		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",

		rx_airtime,

		tx_airtime,

		sta->airtime_weight,

		deficit[0],

		deficit[1],

		deficit[2],

		deficit[3]);



	rv = simple_read_from_buffer(userbuf, count, ppos, buf, p - buf);

	kfree(buf);

	return rv;

}



static ssize_t sta_airtime_write(struct file *file, const char __user *userbuf,

				 size_t count, loff_t *ppos)

{

	struct sta_info *sta = file->private_data;

	struct ieee80211_local *local = sta->sdata->local;

	int ac;



	for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {

		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;

		spin_unlock_bh(&local->active_txq_lock[ac]);

	}



	return count;

}

STA_OPS_RW(airtime);



static ssize_t sta_agg_status_read(struct file *file, char __user *userbuf,

static ssize_t sta_agg_status_read(struct file *file, char __user *userbuf,

					size_t count, loff_t *ppos)

					size_t count, loff_t *ppos)

{

{
@@ -906,6 +964,10 @@ void ieee80211_sta_debugfs_add(struct sta_info *sta) 
	if (local->ops->wake_tx_queue)

	if (local->ops->wake_tx_queue)

		DEBUGFS_ADD(aqm);

		DEBUGFS_ADD(aqm);





	if (wiphy_ext_feature_isset(local->hw.wiphy,

				    NL80211_EXT_FEATURE_AIRTIME_FAIRNESS))

		DEBUGFS_ADD(airtime);



	if (sizeof(sta->driver_buffered_tids) == sizeof(u32))

	if (sizeof(sta->driver_buffered_tids) == sizeof(u32))

		debugfs_create_x32("driver_buffered_tids", 0400,

		debugfs_create_x32("driver_buffered_tids", 0400,

				   sta->debugfs_dir,

				   sta->debugfs_dir,

net/mac80211/ieee80211_i.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -1138,6 +1138,8 @@ struct ieee80211_local { 
	struct list_head active_txqs[IEEE80211_NUM_ACS];

	struct list_head active_txqs[IEEE80211_NUM_ACS];

	u16 schedule_round[IEEE80211_NUM_ACS];

	u16 schedule_round[IEEE80211_NUM_ACS];





	u16 airtime_flags;



	const struct ieee80211_ops *ops;

	const struct ieee80211_ops *ops;





	/*

	/*

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