From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-x22d.google.com (mail-qt0-x22d.google.com [IPv6:2607:f8b0:400d:c0d::22d]) (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 F1B163B2A0 for ; Wed, 30 Nov 2016 21:44:33 -0500 (EST) Received: by mail-qt0-x22d.google.com with SMTP id n6so208181035qtd.1 for ; Wed, 30 Nov 2016 18:44:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:from:date:message-id:subject:to :content-transfer-encoding; bh=yYmacjRdUAQ699lvst7k8AUvei81nRS6goNPiHx313Y=; b=MkRe1h9RzpewZJ534pDyXKhXS3GPr8qoiaxJxFoeLoJ0EbzF1BUmcGMrjnBT125Ya2 2HaUYXYl/v6aZtdAlVT3OPnLGy7NzcUpDtj0FMmDRYiwmSDdGPcrBlYn9w5DR+uaLeo8 nw3cJ25zPUhdQF6rd33GYmgGW5yN/awWCtEo34iiB+xEDQ2oOqbTWnurjcgv6KOqLAPE IUF2NDe7DliQM+3B7MAdUAApPDDobVI8REnk+7Yba9GQdlbVj8IAPoUi/3aiRMbWq0dD q8lw+QPRo5kq7v/jn4mJk6ZGWDhT/LyCM9JUJY3Wej3tMiW2/Zry5Pa2yph4IBPpj4vu qRxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:from:date:message-id:subject:to :content-transfer-encoding; bh=yYmacjRdUAQ699lvst7k8AUvei81nRS6goNPiHx313Y=; b=GYZu3SiQcpyYGajWlrpecOwISdg9WyWCC6jgYqCqjio9PH8vwrELLRjTrfIcUmfAsw tCJvcYqJnJflc587MUQrC7LG6+FmElfmKSK9MIhTSnbvcU+sghE4PB+s7tft/vtA8aUp vLCAciUgqhl2udZ3cSAnss40xNF2j3NVTAIZN2DlSofP1lage6RZfrs+Q7RLZrtxf8PM yYdVHw3hc6RNZgPA16B/KjFZm8VFJV01BWsbJ9ojVNNLHmFj4ew6leIqAtNSH+sMZKJN CND1Un2hGyysP6/691JzY1tHd/A6YkTCsOduPtAafl/aF+APt74kpbqpnoG5b78oWpXe UfoA== X-Gm-Message-State: AKaTC00vAr6zq4tSGSwNBHm0VtcUWp6o5yIQu3V0W4+/oRIrs3ZR+16q1d+JlnE3auZq7wi7lzX0uvj7Q2w0Sg== X-Received: by 10.200.34.73 with SMTP id p9mr36200819qtp.25.1480560273424; Wed, 30 Nov 2016 18:44:33 -0800 (PST) MIME-Version: 1.0 Received: by 10.12.152.197 with HTTP; Wed, 30 Nov 2016 18:44:33 -0800 (PST) From: Dave Taht Date: Wed, 30 Nov 2016 18:44:33 -0800 Message-ID: To: make-wifi-fast@lists.bufferbloat.net Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Make-wifi-fast] some smaller projects (I hope!) 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, 01 Dec 2016 02:44:34 -0000 I went looking through the main make-wifi-fast document and it appears that now that the core patches are landing in linux, that tackling a few more problems would get a lot simpler, and mostly be confined to the mac80211 codebase. It would be good to spin up a few more folk in this part of things (and to get code review of the latest patchsets now that they are in almost-kinda in the kernel). I wouldn't mind if this was a social thing we did on the #bufferbloat irc channel, sometime later this week. Tomorrow morning (thursday) is good. Saturday is good. I used to use irc a lot but with my network perpetually broken or under load I got out of the habit of using it. 1) Reduce advertised TXOP under load This among other things would tell clients to send less data at a time when other stations were heavily contending, benefiting all stations in terms of latency. This is presently a static variable assigned once by hostapd in the conf fi= le see wherever "wmm_ac_vi_txop_limit=3D94" and trace through hostapd for whatever it sets, or grep like crazy. 2) Teach minstrel to be able to create aggregates of any specified duration= . Currently the minstrel_ht code (and darn it, I can't find it now, it's just one function) always tries to form a 4ms aggregate, where being able to form shorter ones also would improve inter-station latency. The simplest thought (once that function was found) would be to look at the backlog for a station and if smaller than the total backlog, halve the aggregate size. Something cleverer might try to shrink things more dynamically (3,2,1.5) based on the number of stations backlogged. 3) Fix the VI queue This has been broken for years, and the above two mods would fix it. VI queue is limited to 1ms and if you put bigger packet trains in it that that, barfs. 4) Make mac80211 codel params configurable Presently not exposed, and defaulting to overlarge defaults 5) Clean up the existing "aqm" stats file to be more human readable 6) Reduce various retries I have no idea why the ath9k defaults to 31 fixed retries. I'd like to see minstrel (this is harder work) form shorter retry chains in general, also. 7) Remove reorder buffers (and see what happens) - somewhere. I am not sure what drivers actually use this facility, but i think the iwl is one. ... Anyway, after that sort of cruft removal, I'd like to go back to looking at how the codel algorithm performs (I outlined some potential changes in the lwn article's comments) --=20 Dave T=C3=A4ht Let's go make home routers and wifi faster! With better software! http://blog.cerowrt.org