Received: by 2002:a25:d7c1:0:0:0:0:0 with SMTP id o184csp1778847ybg; Sat, 19 Oct 2019 02:19:23 -0700 (PDT) X-Google-Smtp-Source: APXvYqzmhbFiMxdeeKmf5YXLNE/TL0KQAZpLddzJNLfrcKb9byznrCfw5tLDndW7TKJMUGXi9ARk X-Received: by 2002:a17:906:ce2e:: with SMTP id sd14mr12921166ejb.197.1571476762854; Sat, 19 Oct 2019 02:19:22 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1571476762; cv=none; d=google.com; s=arc-20160816; b=MecVKmAQQyQwjFkfJoxJcBa0J/DAPRnVLK2TaRoRE0Q0tdfJFsHMOyo6EBoxmhd/qD cfNMtFqr85n4kXBlK3cRQFWTJOXp9wDW4pAGxSzN8yF7cqChDhRNqH94WxQ3L4/RppjV rO9iYYDL3o79/jQXJ5unXljr0VYOuwkBXWkc/hD8sOor7hW/wiFRgK4LqmLIecQ12IEr xAn2RONOUrUzarxaHVLArRlHaOhHCtel7JU4embRKHeAuDH8d6+46A+7Qi+8qNhP5yw9 sDk2yNzwCHXHQmp1wCMHWA0TV1c6r4Gf6tSCMAx1nFp9Cfr+I62/Zw9o5QaIcHJwnhtM 66FA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:cc:to:subject :message-id:date:from:in-reply-to:references:mime-version :dkim-signature; bh=+Up8Gwyf2iZnRutPZhnyYKV6yPtTDybg21nimSnweeU=; b=eZLO9r0SNeJqCQ0HD4hhvJxj4VIUqCT/PVUGNBgR90gCxOGrccPk8iJbJLfMtIboM4 55Y48vEfFVzHIesVLt28mEcLNbZbTJ9HSJAB71yYTEpZNZB7eLs3x+O5+yVwWGeSjkRw z7tflzz7DdAa7M4b1BT9fSXJcro4/STo03riRKlCgi3LwplAuRARJBBaq4ouqGGBqqrE LNdjmdjzn9XGUwCBx2Parjk2tN3X4V+sPeZ/AyJbk97jkr9YKvNEZLEtXizhbzgM9Quf ugjHfpdPFpNdLtKIVx1TWum2kUIU+P7/CM/+MKKc98zrCG/a+shme5auoKlkrSE+AnNK 6Qew== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=DO5sbPJ3; spf=pass (google.com: best guess record for domain of linux-wireless-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-wireless-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id ck24si4803818ejb.400.2019.10.19.02.18.58; Sat, 19 Oct 2019 02:19:22 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-wireless-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=DO5sbPJ3; spf=pass (google.com: best guess record for domain of linux-wireless-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-wireless-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2440418AbfJRV0J (ORCPT + 99 others); Fri, 18 Oct 2019 17:26:09 -0400 Received: from mail-lf1-f67.google.com ([209.85.167.67]:42545 "EHLO mail-lf1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727508AbfJRV0I (ORCPT ); Fri, 18 Oct 2019 17:26:08 -0400 Received: by mail-lf1-f67.google.com with SMTP id z12so5720031lfj.9 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=HiaqJUh5fT3te48nnVDWuADCmENPJF1BbZ6KMbwL/QZoH1kcO3LprV5JkyMqeFHNsm epn0vayILRVD3mT28bxuXX3OxMlJPKSY/tCVL2mENnxABFgSt7Cv/ce9HSYa8ozBKmS0 bqdH/lerPSBZSWOTP7t7oV4Xztie2fYgcG8TX0oG/NwxMHHK9CB2wO8cr+N1rHC8JCDq W1a1lxkw72tc5M/5FoDjtmNI5uJ2mN8o0RLlR0hN2RTf51iAcwTXdm7z1TE2WHQ9vm3S VGSDRG/PZ9eYUzhtyA4jgHtfUtelxaNqJQG9SWm5XI3nP6dUckiNZGVCbooc0rFXPwO7 iGmQ== X-Gm-Message-State: APjAAAWXJ5gqctLlsUEbdBs43Jg3tzhJ6JjkRVgMvcS2oMh0yULjQPOr GlgVrcHwztU1SnIp0eOF+lqvPunUTEw85eUeRfz5sg== 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: Subject: Re: [PATCH v3 4/4] mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue 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 Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org > + 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: >