From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-x22b.google.com (mail-qk0-x22b.google.com [IPv6:2607:f8b0:400d:c09::22b]) (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 A39813BA8E for ; Mon, 9 Oct 2017 16:13:19 -0400 (EDT) Received: by mail-qk0-x22b.google.com with SMTP id w63so24734419qkd.10 for ; Mon, 09 Oct 2017 13:13:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to :content-transfer-encoding; bh=F4i0JrtRU8fYRwxCJZyB2X5ftCXErB+jRGhzFhxzWZ0=; b=EaLMqeqSBK2caT6r5SCVWtlZBGmoW41UL4kg2J8KiOx83tdj/yn436Jib0fEYd302C A+9seB1fDkps9Dwn6vKR+pL2yKryh7jOj5d9kWc1GxD9Efwo5mnpK+2c7oLMFOBZ7EDi tWyHv/AReXm1/ZNkkLhsroRpBjfKRsJpMirTtFSZONbkqykvZ35hd268E/URfROwps/r wa8pAuPqllqjUTJRhN7DnOH+FwLAxjg/WC6lXilKeVqjWSIf8cdCvRmrSRbtPgyjkbZt mG98RzPUEg9gTyGAgtm2DqYuj87Xv/WHslvcIMMUvAe9IgPh4P67lSFYSHSK4qmEzBcM 0HNA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to :content-transfer-encoding; bh=F4i0JrtRU8fYRwxCJZyB2X5ftCXErB+jRGhzFhxzWZ0=; b=GDfNie/PyZ8oz5UqfgMVdo1P7ZugRYmk5no6EI8u9N4RUzDZjRUDlb13IxALQnHxUy WDtvxzPZ86vYIuD6D2HPqUoCQ4nP/ZvYro8ZzSH8ZJjsESECCQgQZ4vi3eaFgj1x04Fl SjlRHrExpOWwzjcVrvghH7MO/CF+isClbuY7ZmkMkZga65gcp39PZliJHuEJO/mmNKJq IF5xNweHQ8BhvWEl4nAqBQib+FphR58xdWG6txUGgYCBRZ0e6X6y3p7Z2jT3yT8wkhTp v3dbgyP9jGdVyuehM55IoR7lIU0Cu36iXxcyWVmtWsOF1zFgwgg71fXBOjILyFfNN8X0 AL4Q== X-Gm-Message-State: AMCzsaXBpU1KnPSqIfbCSjzb4VmIgfABhC2gFXxkwLhJSuGs09yfNHm+ KV3j9RJ/nIaYfBVPVFJ/hBID9HB2uJzmvCm3x9qglA== X-Google-Smtp-Source: AOwi7QCJr04QX5gZPsyDxbw++g3QWpT/uv/2+fNm09zaxO90+LGld4qNUtWo9lE3nTCw5kCfdmmf8j/fRR80s7Fz+Po= X-Received: by 10.55.144.5 with SMTP id s5mr33274qkd.63.1507579998977; Mon, 09 Oct 2017 13:13:18 -0700 (PDT) MIME-Version: 1.0 Received: by 10.12.193.115 with HTTP; Mon, 9 Oct 2017 13:13:18 -0700 (PDT) From: Dave Taht Date: Mon, 9 Oct 2017 13:13:18 -0700 Message-ID: To: make-wifi-fast@lists.bufferbloat.net, Johannes Berg Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: [Make-wifi-fast] less latency, more filling... for wifi 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: Mon, 09 Oct 2017 20:13:19 -0000 There were five ideas I'd wanted to pursue at some point. I''m not presently on linux-wireless, nor do I have time to pay attention right now - but I'm enjoying that thread passively. To get those ideas "out there" again: * adding a fixed length fq'd queue for multicast. * Reducing retransmits at low rates See the recent paper: "Resolving Bufferbloat in TCP Communication over IEEE 802.11 n WLAN by Reducing MAC Retransmission Limit at Low Data Rate" (I'd paste a link but for some reason that doesn't work well) Even with their simple bi-modal model it worked pretty well. It also reduces contention with "bad" stations more automagically. * Less buffering at the driver. Presently (ath9k) there are two-three aggregates stacked up at the driver. With a good estimate for how long it will take to service one, forming another within that deadline seems feasible, so you only need to have one in the hardware itself. Simple example: you have data in the hardware projected to take a minimum of 4ms to transmit. Don't form a new aggregate and submit it to the hardware for 3.5ms. I know full well that a "good" estimate is hard, and things like mu-mimo complicate things. Still, I'd like to get below 20ms of latency within the driver, and this is one way to get there. * Reducing the size of a txop under contention if you have 5 stations getting blasted away at 5ms each, and one that only wants 1ms worth of traffic, "soon", temporarily reducing the size of the txop for everybody so you can service more stations faster, seems useful. * Merging acs when sane to do so sane aggregation in general works better than prioritizing does, as shown in ending the anomaly. --=20 Dave T=C3=A4ht CEO, TekLibre, LLC http://www.teklibre.com Tel: 1-669-226-2619