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From:   Baligh Gasmi <gasmibal@gmail.com>
To:     Johannes Berg <johannes@sipsolutions.net>
Cc:     Baligh Gasmi <gasmibal@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        linux-wireless@vger.kernel.org (open list:MAC80211),
        netdev@vger.kernel.org (open list:NETWORKING [GENERAL]),
        linux-kernel@vger.kernel.org (open list)
Subject: [RFC PATCH 1/1] mac80211: use AQL airtime for expected throughput.
Date:   Wed, 25 May 2022 12:35:12 +0200
Message-Id: <20220525103512.3666956-1-gasmibal@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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. If the driver has
get_expected_throughput implementation, it will be used instead.

Useful for L2 routing protocols, like B.A.T.M.A.N.

Signed-off-by: Baligh Gasmi <gasmibal@gmail.com>
---
 net/mac80211/driver-ops.h |  2 ++
 net/mac80211/sta_info.h   |  2 ++
 net/mac80211/status.c     | 22 ++++++++++++++++++++++
 net/mac80211/tx.c         |  3 ++-
 4 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index 4e2fc1a08681..4331b79647fa 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->status_stats.avg_est_tp);
 	trace_drv_return_u32(local, ret);
 
 	return ret;
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 379fd367197f..fe60be4c671d 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,
@@ -641,6 +642,7 @@ struct 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;
 	} status_stats;
 
 	/* Updated from TX path only, no locking requirements */
diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index e81e8a5bb774..647ade3719f5 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -1145,6 +1145,28 @@ void ieee80211_tx_status_ext(struct ieee80211_hw *hw,
 			sta->status_stats.retry_failed++;
 		sta->status_stats.retry_count += retry_count;
 
+		if (skb && tx_time_est) {
+			/* max average packet size */
+			size_t pkt_size = skb->len > 1024 ? 1024 : skb->len;
+
+			if (acked) {
+				/* ACK packet size */
+				pkt_size += 14;
+				/* SIFS x 2 */
+				tx_time_est += 2 * 2;
+			}
+
+			/* Backoff average x retries */
+			tx_time_est += retry_count ? retry_count * 2 : 2;
+
+			/* failed tx */
+			if (!acked && !noack_success)
+				pkt_size = 0;
+
+			ewma_avg_est_tp_add(&sta->status_stats.avg_est_tp,
+					    ((pkt_size * 8) * 1000) / tx_time_est);
+		}
+
 		if (ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS)) {
 			if (sdata->vif.type == NL80211_IFTYPE_STATION &&
 			    skb && !(info->flags & IEEE80211_TX_CTL_HW_80211_ENCAP))
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index b6b20f38de0e..d866a721690d 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -3793,7 +3793,8 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
 	IEEE80211_SKB_CB(skb)->control.vif = vif;
 
 	if (vif &&
-	    wiphy_ext_feature_isset(local->hw.wiphy, NL80211_EXT_FEATURE_AQL)) {
+	    (!local->ops->get_expected_throughput ||
+	    wiphy_ext_feature_isset(local->hw.wiphy, NL80211_EXT_FEATURE_AQL))) {
 		bool ampdu = txq->ac != IEEE80211_AC_VO;
 		u32 airtime;
 
-- 
2.36.1