From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f53.google.com (mail-ed1-f53.google.com [209.85.208.53]) (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 4F64F3BA8E for ; Tue, 5 Mar 2019 10:45:50 -0500 (EST) Received: by mail-ed1-f53.google.com with SMTP id f2so7595555edy.13 for ; Tue, 05 Mar 2019 07:45:50 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version:content-transfer-encoding; bh=rxj+mSh+wWBLvZbSVbS2ycCqaXjf5XQapmLLhn9oNTQ=; b=GVecx97zxGCMC62T/qzVFwnljJ3D2hM5P/FhXPOr1bFfQ0gE0bDsVOF/JpiIMGUVc2 EEGR0dY6PJ9qR8+I3jk5vLJqrcQ4RN1F06ZHal6gDOqtE3paCYYYjMIG4blkxuGAwqs8 VDH1ZqbLkKg+498DLiMwSb7vu2WiKn1+RkyRUeb0obUdXsUXzjVbaX3dnd28VnCp6CWW YvEMqgLoAFGtueQZvvwMWCEryMyFA9ObXlUOp+sguUKWIuRa8sZ1Ly9VzezLbBkyfBt/ qg4I2oMKzZxfkRz/Wub5X2iX0EkCLx2R32wyziVNm7xG72KJjOZXICzPA7CT/VGX0/S6 HN6Q== X-Gm-Message-State: APjAAAVR3ve22aCCTR/fGgfdECd6lJ4AcIUrVyHdLQJk1HI+bvh+DVcH WS97+MAeMJpUleHMdcgxFrR0GQ== X-Google-Smtp-Source: APXvYqytgs6Ajs2s0x0Q/WS1LAVHHs16rTlbXSA7hos38jXNuJkoRRDz/Wot08VO0csTRyV7jaNQaA== X-Received: by 2002:a05:6402:1495:: with SMTP id e21mr19772510edv.52.1551800749364; Tue, 05 Mar 2019 07:45:49 -0800 (PST) Received: from alrua-x1.borgediget.toke.dk (alrua-x1.vpn.toke.dk. [2a00:7660:6da:10::2]) by smtp.gmail.com with ESMTPSA id i20sm1474686ejv.26.2019.03.05.07.45.48 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 05 Mar 2019 07:45:48 -0800 (PST) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 3F5C4182F35; Tue, 5 Mar 2019 16:45:48 +0100 (CET) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: make-wifi-fast@lists.bufferbloat.net, linux-wireless@vger.kernel.org Cc: Felix Fietkau , Rajkumar Manoharan , Kan Yan In-Reply-To: <20190215170512.31512-1-toke@redhat.com> References: <20190215170512.31512-1-toke@redhat.com> X-Clacks-Overhead: GNU Terry Pratchett Date: Tue, 05 Mar 2019 16:45:48 +0100 Message-ID: <87va0x1g0j.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Make-wifi-fast] [RFC/RFT] mac80211: Switch to a virtual time-based airtime scheduler 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: Tue, 05 Mar 2019 15:45:50 -0000 Toke H=C3=B8iland-J=C3=B8rgensen writes: > This switches the airtime scheduler in mac80211 to use a virtual time-bas= ed > scheduler instead of the round-robin scheduler used before. This has a > couple of advantages: > > - No need to sync up the round-robin scheduler in firmware/hardware with > the round-robin airtime scheduler. > > - If several stations are eligible for transmission we can schedule both = of > them; no need to hard-block the scheduling rotation until the head of t= he > queue has used up its quantum. > > - The check of whether a station is eligible for transmission becomes > simpler (in ieee80211_txq_may_transmit()). > > The drawback is that scheduling becomes slightly more expensive, as we ne= ed > to maintain an rbtree of TXQs sorted by virtual time. This means that > ieee80211_register_airtime() becomes O(logN) in the number of currently > scheduled TXQs. However, hopefully this number rarely grows too big (it's > only TXQs currently backlogged, not all associated stations), so it > shouldn't be too big of an issue. > > Signed-off-by: Toke H=C3=B8iland-J=C3=B8rgensen > --- > This is basically the idea I mentioned earlier for a different way to > handle the airtime scheduling. > > I've tested it on ath9k, where it achieves the same fairness and > weighing properties as the old scheduler. It would be good if you could > test it on your ath10k setup, Rajkumar; and all of you please comment on > whether you agree that this is better from an API point of view. So no one has any comments on this? :) -Toke