From: Kan Yan <kyan@google.com> To: "Toke Høiland-Jørgensen" <toke@redhat.com> Cc: Johannes Berg <johannes@sipsolutions.net>, linux-wireless@vger.kernel.org, Make-Wifi-fast <make-wifi-fast@lists.bufferbloat.net>, ath10k@lists.infradead.org, John Crispin <john@phrozen.org>, Lorenzo Bianconi <lorenzo@kernel.org>, Felix Fietkau <nbd@nbd.name>, Rajkumar Manoharan <rmanohar@codeaurora.org>, Kevin Hayes <kevinhayes@google.com> Subject: Re: [PATCH v4 4/4] mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue Date: Mon, 21 Oct 2019 23:20:34 -0700 [thread overview] Message-ID: <CA+iem5sy16=xMZjJi1nKHrxP_xWHk-86G=ZLwtMMb04EOt5tQA@mail.gmail.com> (raw) In-Reply-To: <157148503865.2989444.7118792679603045723.stgit@toke.dk> > + if (ieee80211_is_data_qos(hdr->frame_control)) { > + qc = ieee80211_get_qos_ctl(hdr); > + tid = qc[0] & 0xf; > + ac = ieee80211_ac_from_tid(tid); > + } else { > + ac = IEEE80211_AC_BE; > + } The tid/ac is incorrect either here or in __ieee80211_tx_status() when tested with ath10k. The ac is set to AC_BE with test done using BK class traffic, hence the pending airtime get updated for the wrong txq. The rest of the patch seems to work as expected, after I did a quick hack to release the pending airtime from ath10k_txrx_tx_unref() instead, where the ac/tid can be directly retrieved from struck struct ieee80211_tx. On Sat, Oct 19, 2019 at 4:37 AM Toke Høiland-Jørgensen <toke@redhat.com> wrote: > > From: Toke Høiland-Jørgensen <toke@redhat.com> > > The previous commit added the ability to throttle stations when they queue > too much airtime in the hardware. This commit enables the functionality by > calculating the expected airtime usage of each packet that is dequeued from > the TXQs in mac80211, and accounting that as pending airtime. > > The estimated airtime for each skb is stored in the tx_info, so we can > subtract the same amount from the running total when the skb is freed or > recycled. The throttling mechanism relies on this accounting to be > accurate (i.e., that we are not freeing skbs without subtracting any > airtime they were accounted for), so we put the subtraction into > ieee80211_report_used_skb(). As an optimisation, we also subtract the > airtime on regular TX completion, zeroing out the value stored in the > packet afterwards, to avoid having to do an expensive lookup of the > station from the packet data on every packet. > > This patch does *not* include any mechanism to wake a throttled TXQ again, > on the assumption that this will happen anyway as a side effect of whatever > freed the skb (most commonly a TX completion). > > Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> > --- > net/mac80211/status.c | 38 ++++++++++++++++++++++++++++++++++++++ > net/mac80211/tx.c | 21 +++++++++++++++++++++ > 2 files changed, 59 insertions(+) > > diff --git a/net/mac80211/status.c b/net/mac80211/status.c > index ab8ba5835ca0..905b4afd457d 100644 > --- a/net/mac80211/status.c > +++ b/net/mac80211/status.c > @@ -676,6 +676,33 @@ static void ieee80211_report_used_skb(struct ieee80211_local *local, > if (dropped) > acked = false; > > + if (info->tx_time_est) { > + struct ieee80211_sub_if_data *sdata; > + struct sta_info *sta = NULL; > + u8 *qc, ac; > + int tid; > + > + rcu_read_lock(); > + > + sdata = ieee80211_sdata_from_skb(local, skb); > + if (sdata) > + sta = sta_info_get_bss(sdata, skb_mac_header(skb)); > + > + if (ieee80211_is_data_qos(hdr->frame_control)) { > + qc = ieee80211_get_qos_ctl(hdr); > + tid = qc[0] & 0xf; > + ac = ieee80211_ac_from_tid(tid); > + } else { > + ac = IEEE80211_AC_BE; > + } > + > + ieee80211_sta_update_pending_airtime(local, sta, ac, > + info->tx_time_est << 2, > + true); > + rcu_read_unlock(); > + > + } > + > if (info->flags & IEEE80211_TX_INTFL_MLME_CONN_TX) { > struct ieee80211_sub_if_data *sdata; > > @@ -930,6 +957,17 @@ static void __ieee80211_tx_status(struct ieee80211_hw *hw, > tid = qc[0] & 0xf; > } > > + if (info->tx_time_est) { > + /* Do this here to avoid the expensive lookup of the sta > + * in ieee80211_report_used_skb(). > + */ > + ieee80211_sta_update_pending_airtime(local, sta, > + ieee80211_ac_from_tid(tid), > + info->tx_time_est << 2, > + true); > + info->tx_time_est = 0; > + } > + > if (!acked && ieee80211_is_back_req(fc)) { > u16 control; > > diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c > index 12653d873b8c..b8ff56d1d661 100644 > --- a/net/mac80211/tx.c > +++ b/net/mac80211/tx.c > @@ -3542,6 +3542,9 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw, > > WARN_ON_ONCE(softirq_count() == 0); > > + if (!ieee80211_txq_airtime_check(hw, txq)) > + return NULL; > + > begin: > spin_lock_bh(&fq->lock); > > @@ -3652,6 +3655,24 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw, > } > > IEEE80211_SKB_CB(skb)->control.vif = vif; > + > + if (local->airtime_flags & AIRTIME_USE_AQL) { > + u32 airtime; > + > + airtime = ieee80211_calc_expected_tx_airtime(hw, vif, txq->sta, > + skb->len); > + if (airtime) { > + /* We only have 10 bits in tx_time_est, so store airtime > + * in increments of 4 us and clamp the maximum to 2**12-1 > + */ > + airtime = min_t(u32, airtime, 4095) & ~3U; > + info->tx_time_est = airtime >> 2; > + ieee80211_sta_update_pending_airtime(local, tx.sta, > + txq->ac, airtime, > + false); > + } > + } > + > return skb; > > out: >
WARNING: multiple messages have this Message-ID (diff)
From: Kan Yan <kyan@google.com> To: "Toke Høiland-Jørgensen" <toke@redhat.com> Cc: Rajkumar Manoharan <rmanohar@codeaurora.org>, Kevin Hayes <kevinhayes@google.com>, Make-Wifi-fast <make-wifi-fast@lists.bufferbloat.net>, linux-wireless@vger.kernel.org, ath10k@lists.infradead.org, John Crispin <john@phrozen.org>, Johannes Berg <johannes@sipsolutions.net>, Lorenzo Bianconi <lorenzo@kernel.org>, Felix Fietkau <nbd@nbd.name> Subject: Re: [PATCH v4 4/4] mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue Date: Mon, 21 Oct 2019 23:20:34 -0700 [thread overview] Message-ID: <CA+iem5sy16=xMZjJi1nKHrxP_xWHk-86G=ZLwtMMb04EOt5tQA@mail.gmail.com> (raw) In-Reply-To: <157148503865.2989444.7118792679603045723.stgit@toke.dk> > + if (ieee80211_is_data_qos(hdr->frame_control)) { > + qc = ieee80211_get_qos_ctl(hdr); > + tid = qc[0] & 0xf; > + ac = ieee80211_ac_from_tid(tid); > + } else { > + ac = IEEE80211_AC_BE; > + } The tid/ac is incorrect either here or in __ieee80211_tx_status() when tested with ath10k. The ac is set to AC_BE with test done using BK class traffic, hence the pending airtime get updated for the wrong txq. The rest of the patch seems to work as expected, after I did a quick hack to release the pending airtime from ath10k_txrx_tx_unref() instead, where the ac/tid can be directly retrieved from struck struct ieee80211_tx. On Sat, Oct 19, 2019 at 4:37 AM Toke Høiland-Jørgensen <toke@redhat.com> wrote: > > From: Toke Høiland-Jørgensen <toke@redhat.com> > > The previous commit added the ability to throttle stations when they queue > too much airtime in the hardware. This commit enables the functionality by > calculating the expected airtime usage of each packet that is dequeued from > the TXQs in mac80211, and accounting that as pending airtime. > > The estimated airtime for each skb is stored in the tx_info, so we can > subtract the same amount from the running total when the skb is freed or > recycled. The throttling mechanism relies on this accounting to be > accurate (i.e., that we are not freeing skbs without subtracting any > airtime they were accounted for), so we put the subtraction into > ieee80211_report_used_skb(). As an optimisation, we also subtract the > airtime on regular TX completion, zeroing out the value stored in the > packet afterwards, to avoid having to do an expensive lookup of the > station from the packet data on every packet. > > This patch does *not* include any mechanism to wake a throttled TXQ again, > on the assumption that this will happen anyway as a side effect of whatever > freed the skb (most commonly a TX completion). > > Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> > --- > net/mac80211/status.c | 38 ++++++++++++++++++++++++++++++++++++++ > net/mac80211/tx.c | 21 +++++++++++++++++++++ > 2 files changed, 59 insertions(+) > > diff --git a/net/mac80211/status.c b/net/mac80211/status.c > index ab8ba5835ca0..905b4afd457d 100644 > --- a/net/mac80211/status.c > +++ b/net/mac80211/status.c > @@ -676,6 +676,33 @@ static void ieee80211_report_used_skb(struct ieee80211_local *local, > if (dropped) > acked = false; > > + if (info->tx_time_est) { > + struct ieee80211_sub_if_data *sdata; > + struct sta_info *sta = NULL; > + u8 *qc, ac; > + int tid; > + > + rcu_read_lock(); > + > + sdata = ieee80211_sdata_from_skb(local, skb); > + if (sdata) > + sta = sta_info_get_bss(sdata, skb_mac_header(skb)); > + > + if (ieee80211_is_data_qos(hdr->frame_control)) { > + qc = ieee80211_get_qos_ctl(hdr); > + tid = qc[0] & 0xf; > + ac = ieee80211_ac_from_tid(tid); > + } else { > + ac = IEEE80211_AC_BE; > + } > + > + ieee80211_sta_update_pending_airtime(local, sta, ac, > + info->tx_time_est << 2, > + true); > + rcu_read_unlock(); > + > + } > + > if (info->flags & IEEE80211_TX_INTFL_MLME_CONN_TX) { > struct ieee80211_sub_if_data *sdata; > > @@ -930,6 +957,17 @@ static void __ieee80211_tx_status(struct ieee80211_hw *hw, > tid = qc[0] & 0xf; > } > > + if (info->tx_time_est) { > + /* Do this here to avoid the expensive lookup of the sta > + * in ieee80211_report_used_skb(). > + */ > + ieee80211_sta_update_pending_airtime(local, sta, > + ieee80211_ac_from_tid(tid), > + info->tx_time_est << 2, > + true); > + info->tx_time_est = 0; > + } > + > if (!acked && ieee80211_is_back_req(fc)) { > u16 control; > > diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c > index 12653d873b8c..b8ff56d1d661 100644 > --- a/net/mac80211/tx.c > +++ b/net/mac80211/tx.c > @@ -3542,6 +3542,9 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw, > > WARN_ON_ONCE(softirq_count() == 0); > > + if (!ieee80211_txq_airtime_check(hw, txq)) > + return NULL; > + > begin: > spin_lock_bh(&fq->lock); > > @@ -3652,6 +3655,24 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw, > } > > IEEE80211_SKB_CB(skb)->control.vif = vif; > + > + if (local->airtime_flags & AIRTIME_USE_AQL) { > + u32 airtime; > + > + airtime = ieee80211_calc_expected_tx_airtime(hw, vif, txq->sta, > + skb->len); > + if (airtime) { > + /* We only have 10 bits in tx_time_est, so store airtime > + * in increments of 4 us and clamp the maximum to 2**12-1 > + */ > + airtime = min_t(u32, airtime, 4095) & ~3U; > + info->tx_time_est = airtime >> 2; > + ieee80211_sta_update_pending_airtime(local, tx.sta, > + txq->ac, airtime, > + false); > + } > + } > + > return skb; > > out: > _______________________________________________ ath10k mailing list ath10k@lists.infradead.org http://lists.infradead.org/mailman/listinfo/ath10k
next prev parent reply other threads:[~2019-10-22 6:20 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-10-19 11:37 [PATCH v4 0/4] Add Airtime Queue Limits (AQL) to mac80211 Toke Høiland-Jørgensen 2019-10-19 11:37 ` Toke Høiland-Jørgensen 2019-10-19 11:37 ` [PATCH v4 1/4] mac80211: Shrink the size of ack_frame_id to make room for tx_time_est Toke Høiland-Jørgensen 2019-10-19 11:37 ` Toke Høiland-Jørgensen 2019-10-19 11:37 ` [PATCH v4 2/4] mac80211: Import airtime calculation code from mt76 Toke Høiland-Jørgensen 2019-10-19 11:37 ` Toke Høiland-Jørgensen 2019-10-21 22:14 ` kbuild test robot 2019-10-21 22:14 ` kbuild test robot 2019-10-21 22:14 ` kbuild test robot 2019-10-21 22:14 ` [RFC PATCH] mac80211: ieee80211_calc_rx_airtime() can be static kbuild test robot 2019-10-21 22:14 ` kbuild test robot 2019-10-21 22:14 ` kbuild test robot 2019-10-19 11:37 ` [PATCH v4 3/4] mac80211: Implement Airtime-based Queue Limit (AQL) Toke Høiland-Jørgensen 2019-10-19 11:37 ` Toke Høiland-Jørgensen 2019-10-19 11:37 ` [PATCH v4 4/4] mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue Toke Høiland-Jørgensen 2019-10-19 11:37 ` Toke Høiland-Jørgensen 2019-10-22 6:20 ` Kan Yan [this message] 2019-10-22 6:20 ` Kan Yan 2019-10-22 7:14 ` Toke Høiland-Jørgensen 2019-10-22 7:14 ` Toke Høiland-Jørgensen 2019-10-22 11:35 ` Toke Høiland-Jørgensen 2019-10-22 11:35 ` Toke Høiland-Jørgensen 2019-10-23 6:41 ` Kan Yan 2019-10-23 6:41 ` Kan Yan 2019-10-23 8:18 ` Toke Høiland-Jørgensen 2019-10-23 8:18 ` Toke Høiland-Jørgensen 2019-10-23 9:52 ` Toke Høiland-Jørgensen 2019-10-23 9:52 ` Toke Høiland-Jørgensen 2019-10-23 15:43 ` Kan Yan 2019-10-23 15:43 ` Kan Yan [not found] ` <CA+iem5vU-K-+sSSeNugy5ZZF_nH5vuaXW3J_WC=1WWhdkHOgjw@mail.gmail.com> 2019-10-23 21:09 ` Toke Høiland-Jørgensen 2019-10-23 21:09 ` Toke Høiland-Jørgensen
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