Re: [RFC/RFT v5 1/4] mac80211: use AQL airtime for expected throughput.

[Nicolas Escande]

Hello Baligh,

On Tue Jul 19, 2022 at 2:35 PM CEST, Baligh Gasmi wrote:
> Since the integration of AQL, packet TX airtime estimation is
> calculated and counted to be used for the dequeue limit.
>
> Use this estimated airtime to compute expected throughput for
> each station.
>
> It will be a generic mac80211 implementation. that can be used if the
> driver do not have get_expected_throughput implementation.
>
> Useful for L2 routing protocols, like B.A.T.M.A.N.
>
> Signed-off-by: Baligh Gasmi <gasmibal@xxxxxxxxx>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> CC: Felix Fietkau <nbd@xxxxxxxx>
> ---
>  net/mac80211/driver-ops.h |  2 ++
>  net/mac80211/sta_info.c   | 39 +++++++++++++++++++++++++++++++++++++++
>  net/mac80211/sta_info.h   | 11 +++++++++++
>  net/mac80211/status.c     |  2 ++
>  net/mac80211/tx.c         |  8 +++++++-
>  5 files changed, 61 insertions(+), 1 deletion(-)
>
> diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
> index 4e2fc1a08681..fa9952154795 100644
> --- a/net/mac80211/driver-ops.h
> +++ b/net/mac80211/driver-ops.h
> @@ -1142,6 +1142,8 @@ static inline u32 drv_get_expected_throughput(struct ieee80211_local *local,
>  	trace_drv_get_expected_throughput(&sta->sta);
>  	if (local->ops->get_expected_throughput && sta->uploaded)
>  		ret = local->ops->get_expected_throughput(&local->hw, &sta->sta);
> +	else
> +		ret = ewma_avg_est_tp_read(&sta->deflink.status_stats.avg_est_tp);
>  	trace_drv_return_u32(local, ret);
>
>  	return ret;
> diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
> index e04a0905e941..201aab465234 100644
> --- a/net/mac80211/sta_info.c
> +++ b/net/mac80211/sta_info.c
> @@ -1993,6 +1993,45 @@ void ieee80211_sta_update_pending_airtime(struct ieee80211_local *local,
>  			       tx_pending, 0);
>  }
>
> +void ieee80211_sta_update_tp(struct ieee80211_local *local,
> +			     struct sta_info *sta,
> +			     struct sk_buff *skb,
> +			     u16 tx_time_est,
> +			     bool ack, int retry)
> +{
> +	unsigned long diff;
> +	struct rate_control_ref *ref = NULL;
> +
> +	if (!skb || !sta || !tx_time_est)
> +		return;
> +
> +	if (test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
> +		ref = sta->rate_ctrl;
> +
> +	if (ref && ref->ops->get_expected_throughput)
> +		return;
> +
> +	if (local->ops->get_expected_throughput)
> +		return;
> +
> +	tx_time_est += ack ? 4 : 0;
> +	tx_time_est += retry ? retry * 2 : 2;
> +
> +	sta->deflink.tx_stats.tp_tx_size += (skb->len * 8) * 1000;
> +	sta->deflink.tx_stats.tp_tx_time_est += tx_time_est;
> +
> +	diff = jiffies - sta->deflink.status_stats.last_tp_update;
> +	if (diff > HZ / 10) {
> +		ewma_avg_est_tp_add(&sta->deflink.status_stats.avg_est_tp,
> +				    sta->deflink.tx_stats.tp_tx_size /
> +				    sta->deflink.tx_stats.tp_tx_time_est);
This needs a div_u64(), the arch may not have native 64 bits div support
> +
> +		sta->deflink.tx_stats.tp_tx_size = 0;
> +		sta->deflink.tx_stats.tp_tx_time_est = 0;
> +		sta->deflink.status_stats.last_tp_update = jiffies;
> +	}
> +}
> +
>  int sta_info_move_state(struct sta_info *sta,
>  			enum ieee80211_sta_state new_state)
>  {
> diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
> index 35c390bedfba..4200856fefcd 100644
> --- a/net/mac80211/sta_info.h
> +++ b/net/mac80211/sta_info.h
> @@ -123,6 +123,7 @@ enum ieee80211_sta_info_flags {
>  #define HT_AGG_STATE_STOP_CB		7
>  #define HT_AGG_STATE_SENT_ADDBA		8
>
> +DECLARE_EWMA(avg_est_tp, 8, 16)
>  DECLARE_EWMA(avg_signal, 10, 8)
>  enum ieee80211_agg_stop_reason {
>  	AGG_STOP_DECLINED,
> @@ -157,6 +158,12 @@ void ieee80211_register_airtime(struct ieee80211_txq *txq,
>
>  struct sta_info;
>
> +void ieee80211_sta_update_tp(struct ieee80211_local *local,
> +			     struct sta_info *sta,
> +			     struct sk_buff *skb,
> +			     u16 tx_time_est,
> +			     bool ack, int retry);
> +
>  /**
>   * struct tid_ampdu_tx - TID aggregation information (Tx).
>   *
> @@ -549,6 +556,8 @@ struct link_sta_info {
>  		s8 last_ack_signal;
>  		bool ack_signal_filled;
>  		struct ewma_avg_signal avg_ack_signal;
> +		struct ewma_avg_est_tp avg_est_tp;
> +		unsigned long last_tp_update;
>  	} status_stats;
>
>  	/* Updated from TX path only, no locking requirements */
> @@ -558,6 +567,8 @@ struct link_sta_info {
>  		struct ieee80211_tx_rate last_rate;
>  		struct rate_info last_rate_info;
>  		u64 msdu[IEEE80211_NUM_TIDS + 1];
> +		u64 tp_tx_size;
> +		u64 tp_tx_time_est;
>  	} tx_stats;
>
>  	enum ieee80211_sta_rx_bandwidth cur_max_bandwidth;
> diff --git a/net/mac80211/status.c b/net/mac80211/status.c
> index e69272139437..1fb93abc1709 100644
> --- a/net/mac80211/status.c
> +++ b/net/mac80211/status.c
> @@ -1152,6 +1152,8 @@ void ieee80211_tx_status_ext(struct ieee80211_hw *hw,
>  	ack_signal_valid >  		!!(info->status.flags & IEEE80211_TX_STATUS_ACK_SIGNAL_VALID);
>
> +	ieee80211_sta_update_tp(local, sta, skb, tx_time_est, acked, retry_count);
> +
>  	if (pubsta) {
>  		struct ieee80211_sub_if_data *sdata = sta->sdata;
>
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index c425f4fb7c2e..beb79b04c287 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -3617,6 +3617,7 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
>  	struct ieee80211_tx_data tx;
>  	ieee80211_tx_result r;
>  	struct ieee80211_vif *vif = txq->vif;
> +	struct rate_control_ref *ref = NULL;
>
>  	WARN_ON_ONCE(softirq_count() == 0);
>
> @@ -3775,8 +3776,13 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
>  encap_out:
>  	IEEE80211_SKB_CB(skb)->control.vif = vif;
>
> +	if (tx.sta && test_sta_flag(tx.sta, WLAN_STA_RATE_CONTROL))
> +		ref = tx.sta->rate_ctrl;
> +
>  	if (vif &&
> -	    wiphy_ext_feature_isset(local->hw.wiphy, NL80211_EXT_FEATURE_AQL)) {
> +	    ((!local->ops->get_expected_throughput &&
> +	     (!ref || !ref->ops->get_expected_throughput)) ||
> +	    wiphy_ext_feature_isset(local->hw.wiphy, NL80211_EXT_FEATURE_AQL))) {
>  		bool ampdu = txq->ac != IEEE80211_AC_VO;
>  		u32 airtime;
>
> --
> 2.37.1