From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-1.mimecast.com (us-smtp-1.mimecast.com [207.211.31.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id A46CE3B29D for ; Thu, 27 Feb 2020 05:07:34 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582798054; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=RlKo2k587pnozXtodVAjUUMy1n4IejEaZppUzBVQs6w=; b=gn83prVjTfObNHJXEfuVg2EJK8jTgKq5EC6k/WhecrFOzEyQRo2yHyTQkd8z6klMNmKYyE p2anowxYAL+uGIQQHY+WhblAmgNMiE3DWTv/NF5y41PwqxNNFMTL4A5P8OlatHSHpDHM2I Xg2DZgAHOl8VwiMtRhlDfBc16PZljC4= Received: from mail-lj1-f198.google.com (mail-lj1-f198.google.com [209.85.208.198]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-387-xn3IHsGZP1ayjE5XLLjwOw-1; Thu, 27 Feb 2020 05:07:32 -0500 X-MC-Unique: xn3IHsGZP1ayjE5XLLjwOw-1 Received: by mail-lj1-f198.google.com with SMTP id t20so719756ljk.20 for ; Thu, 27 Feb 2020 02:07:32 -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=gNmqYYh8IkvOzoThAYHg0T+VuNTkTQWybQ70SZPEJMM=; b=G1paHQ4H6N+dtnL1CPmdugrl8amYA4zI9vciCqtADONwJLH8iXpBQWyP9CBHOlmobT 5pYLfQirxxL8RlgtsEV5aZa0tbSkYmVuisYi2FYjHY9ZoQ2K9FYUbTzNtcSg/tEGlt1f XaRuAlp/Mcd5Wz5niLTJMMwr+m0aIKn3w/6ov3+GoU8G5i/H/3sO0DD4R3/lnf3aJhKq 4p8Sze7w7w9IKcGJDsbcTesBlPXzH6rvSIfvCH3TvnErT0nd9OcJjOG9k+FodDJgN+tF mrxmtbh/lkmYIbRIicYMhxCupRV+xPEMVOOUnYI7zkFsDzXNPtrBK4cB54c/fySG1/eQ 2VJQ== X-Gm-Message-State: ANhLgQ1tIDaXC85XiihPRzBPUXx9Y5EYViVs8eWSVWw2V8DgqzF8nZre M/CT00bBLzgvUix/atEpU7bCrbS9rrPo3qzhVH4KNlxMtUZ4iwH/kGi8ycX5X5YgE9/z5ztvMan 1rJT1hcWC/3QZaKlPyoAKHaM8UsEiCXnC8/A= X-Received: by 2002:ac2:4467:: with SMTP id y7mr1765211lfl.167.1582798051197; Thu, 27 Feb 2020 02:07:31 -0800 (PST) X-Google-Smtp-Source: ADFU+vsgXzP7lGW2gpvb3qLFRp1BhIv/wjC1Y4iIdVaqOc7roMwNM3xAQGYBq/T/10hhj1aEUeDNsw== X-Received: by 2002:ac2:4467:: with SMTP id y7mr1765195lfl.167.1582798050898; Thu, 27 Feb 2020 02:07:30 -0800 (PST) Received: from alrua-x1.borgediget.toke.dk ([45.145.92.2]) by smtp.gmail.com with ESMTPSA id n132sm2974879lfd.81.2020.02.27.02.07.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Feb 2020 02:07:30 -0800 (PST) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 72690180362; Thu, 27 Feb 2020 11:07:29 +0100 (CET) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Felix Fietkau , Kan Yan , johannes@sipsolutions.net Cc: linux-wireless@vger.kernel.org, make-wifi-fast@lists.bufferbloat.net, yiboz@codeaurora.org, john@phrozen.org, lorenzo@kernel.org, rmanohar@codeaurora.org, kevinhayes@google.com In-Reply-To: <829b6b28-99cd-ea9d-fea3-603a10eae401@nbd.name> References: <20191119060610.76681-1-kyan@google.com> <20191119060610.76681-5-kyan@google.com> <789d592c-5b1b-b785-6d9c-86b7cc7d57f4@nbd.name> <87k149xbb4.fsf@toke.dk> <829b6b28-99cd-ea9d-fea3-603a10eae401@nbd.name> X-Clacks-Overhead: GNU Terry Pratchett Date: Thu, 27 Feb 2020 11:07:29 +0100 Message-ID: <875zfsxs0u.fsf@toke.dk> MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Make-wifi-fast] [PATCH v11 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: Thu, 27 Feb 2020 10:07:34 -0000 Felix Fietkau writes: > On 2020-02-26 22:56, Toke H=C3=B8iland-J=C3=B8rgensen wrote: >> Felix Fietkau writes: >>> - We need an API that allows the driver to change the pending airtime >>> values, e.g. subtract estimated tx time for a packet. >>> mt76 an ath9k can queue packets inside the driver that are not currentl= y >>> in the hardware queues. Typically if the txqs have more data than what >>> gets put into the hardware queue, both drivers will pull an extra frame >>> and queue it in its private txq struct. This frame will get used on the >>> next txq scheduling round for that particular station. >>> If you have lots of stations doing traffic (or having driver buffered >>> frames in powersave mode), this could use up a sizable chunk of the AQL >>> budget. >>=20 >> I'm a bit more skeptical about this. If the driver buffers a bunch of >> packets that are not accounted that will hurt that station due to extra >> latency when it wakes up. For ath9k, this is the retry_q you're talking >> about, right? The number of packets queued on that is fairly limited, >> isn't it? What kind of powersave buffering is the driver doing, and why >> can't it leave the packets on the TXQ? That would allow them to be >> scheduled along with any new ones that might have arrived in the >> meantime, which would be a benefit for latency. > For mt76 there should be max. 1 frame in the retry queue, it's just a > frame that was pulled from the txq in a transmission attempt but that it > couldn't put in the hw queue because it didn't fit in the current > aggregate batch. Wait, if it's only a single frame that is queued in the driver, how is this causing problems? We deliberately set the limit so there was a bit of slack above the size of an aggregate for things like this. Could you please describe in a bit more detail what symptoms you are seeing of this problem? :) -Toke