From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf1-x142.google.com (mail-lf1-x142.google.com [IPv6:2a00:1450:4864:20::142]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id CC4D63B2A4 for ; Fri, 18 Oct 2019 17:26:06 -0400 (EDT) Received: by mail-lf1-x142.google.com with SMTP id w6so5744943lfl.2 for ; Fri, 18 Oct 2019 14:26:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=+Up8Gwyf2iZnRutPZhnyYKV6yPtTDybg21nimSnweeU=; b=DO5sbPJ3KT5w7eZ8ZFGjS6kfqG5LY9WT8IS4j5JitX0ihljkLwZSmPqegQujlCweo/ fGd3MSFRvrFRkKfGp2Eb8KKsNVHFwYzUGAsfkix5a+ZEYaEaexTf3EjGK3dPYGcp2jlU YSfTJDBLFL5HlAWxbBg/0cMID3ogTM2lqstSBz17Y1WKzSV5594cUo4LaxC9MVddcTzo 0GGZTFH0FN974RQO1CABlhl39JmjXWvabQJWRWQNf2dDxxJRUbK2SD8ELa8YWuQ23Et/ kGx4uUm15nDgjkz4otNP3yUM0VVNMpDlMm22ijGADdFvR7nLajYNUUrWLAtX27CB6s3u eTPQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=+Up8Gwyf2iZnRutPZhnyYKV6yPtTDybg21nimSnweeU=; b=NDpb6sjTHblIqP6CGKU6Lx9vbZVasTptjycBN8HzSshc7a34tkiJJ2F/9iflT8A6sc 0SIx6d18TuJwqwi0WTJjP53nF6uSp1YZ1knnv+eog7wFq4alj8f+EhqPDInA+3uGPmWU H7/XpMcwe89iIVhgHhYB9apx38JbOUTTGYcHh7mHiBr7OXiqZq5RncJPEp4uUikGv8CH SNymPKVGXVajlOtF1NxfPsnAcpNiPxvFOVSwQimAcKz9TWhCcCxORAvcguzUInUYRWi/ YCdSgxrW0T+A2zVC+jTcAHSWz18xR9MxLUWfIJtCfH1Pa51k4tkBoBzae88kVeTJuPtB UjzA== X-Gm-Message-State: APjAAAU9o7K0TJ0Yu82Ar68wL64Gc2mf60Fvql7yJPNxzEpAmdH8+qS/ NBh/0JFSWeytjVCgVaU4W3oZ1DnHCIXXFVj0vqX4zA== X-Google-Smtp-Source: APXvYqyTnANwrAfiEJAtZi6lCBu2WZC15AbYHqhBi0/lAQnLeSMRlARVOHYFbr9G2RecV9d00MH3gdMP9+vXbh1O0ik= X-Received: by 2002:ac2:5610:: with SMTP id v16mr7187855lfd.93.1571433965266; Fri, 18 Oct 2019 14:26:05 -0700 (PDT) MIME-Version: 1.0 References: <157140962094.2866668.3383184317264069493.stgit@toke.dk> <157140962534.2866668.1182822483250825739.stgit@toke.dk> In-Reply-To: <157140962534.2866668.1182822483250825739.stgit@toke.dk> From: Kan Yan Date: Fri, 18 Oct 2019 14:25:53 -0700 Message-ID: To: =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= Cc: Johannes Berg , linux-wireless@vger.kernel.org, Make-Wifi-fast , ath10k@lists.infradead.org, John Crispin , Lorenzo Bianconi , Felix Fietkau , Rajkumar Manoharan , Kevin Hayes Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Make-wifi-fast] [PATCH v3 4/4] mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue X-BeenThere: make-wifi-fast@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 18 Oct 2019 21:26:07 -0000 > + if (local->airtime_flags & AIRTIME_USE_AQL) { > + airtime =3D ieee80211_calc_expected_tx_airtime(hw, vif, t= xq->sta, > + skb->len); > + if (airtime) { > + /* We only have 10 bits in tx_time_est, so store = airtime > + * in increments of 4 us and clamp that to 2**10. > + */ > + info->tx_time_est =3D min_t(u32, airtime >> 2, 1 = << 10); > + ieee80211_sta_update_pending_airtime(local, tx.st= a, ac, > + airtime, fal= se); > + } > + } > + It should be: ieee80211_sta_update_pending_airtime(local, tx.sta= , ac, info->tx_time_est << 2, false); The airtime rounded to 4us (info->tx_time_est << 2), instead of the original airtime should be used when registering the pending airtime, to keep it consistent with airtime subtracted when the skb is freed. On Fri, Oct 18, 2019 at 7:40 AM Toke H=C3=B8iland-J=C3=B8rgensen wrote: > > From: Toke H=C3=B8iland-J=C3=B8rgensen > > The previous commit added the ability to throttle stations when they queu= e > too much airtime in the hardware. This commit enables the functionality b= y > calculating the expected airtime usage of each packet that is dequeued fr= om > 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 whatev= er > freed the skb (most commonly a TX completion). > > Signed-off-by: Toke H=C3=B8iland-J=C3=B8rgensen > --- > net/mac80211/status.c | 38 ++++++++++++++++++++++++++++++++++++++ > net/mac80211/tx.c | 19 +++++++++++++++++++ > 2 files changed, 57 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 ieee802= 11_local *local, > if (dropped) > acked =3D false; > > + if (info->tx_time_est) { > + struct ieee80211_sub_if_data *sdata; > + struct sta_info *sta =3D NULL; > + u8 *qc, ac; > + int tid; > + > + rcu_read_lock(); > + > + sdata =3D ieee80211_sdata_from_skb(local, skb); > + if (sdata) > + sta =3D sta_info_get_bss(sdata, skb_mac_header(sk= b)); > + > + if (ieee80211_is_data_qos(hdr->frame_control)) { > + qc =3D ieee80211_get_qos_ctl(hdr); > + tid =3D qc[0] & 0xf; > + ac =3D ieee80211_ac_from_tid(tid); > + } else { > + ac =3D 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_h= w *hw, > tid =3D 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_tim= e_est << 2, > + true); > + info->tx_time_est =3D 0; > + } > + > if (!acked && ieee80211_is_back_req(fc)) { > u16 control; > > diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c > index 12653d873b8c..bd8284f04361 100644 > --- a/net/mac80211/tx.c > +++ b/net/mac80211/tx.c > @@ -3539,9 +3539,14 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80= 211_hw *hw, > struct ieee80211_tx_data tx; > ieee80211_tx_result r; > struct ieee80211_vif *vif =3D txq->vif; > + u8 ac =3D txq->ac; > + u32 airtime; > > WARN_ON_ONCE(softirq_count() =3D=3D 0); > > + if (!ieee80211_txq_airtime_check(hw, txq)) > + return NULL; > + > begin: > spin_lock_bh(&fq->lock); > > @@ -3652,6 +3657,20 @@ struct sk_buff *ieee80211_tx_dequeue(struct ieee80= 211_hw *hw, > } > > IEEE80211_SKB_CB(skb)->control.vif =3D vif; > + > + if (local->airtime_flags & AIRTIME_USE_AQL) { > + airtime =3D ieee80211_calc_expected_tx_airtime(hw, vif, t= xq->sta, > + skb->len); > + if (airtime) { > + /* We only have 10 bits in tx_time_est, so store = airtime > + * in increments of 4 us and clamp that to 2**10. > + */ > + info->tx_time_est =3D min_t(u32, airtime >> 2, 1 = << 10); > + ieee80211_sta_update_pending_airtime(local, tx.st= a, ac, > + airtime, fal= se); > + } > + } > + > return skb; > > out: >