From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-x234.google.com (mail-io0-x234.google.com [IPv6:2607:f8b0:4001:c06::234]) (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 DDCA43B25E for ; Tue, 10 May 2016 03:17:56 -0400 (EDT) Received: by mail-io0-x234.google.com with SMTP id f89so6331071ioi.0 for ; Tue, 10 May 2016 00:17:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc; bh=MB6nZL3xhaWlHrv//pvMDuvaWhVpvOIkiDoAkvkrHrA=; b=viCEdWaqxZ6RXtem1LFhBO4oP6Hsf/iMgaEjRQKB2dwlxOJXMT4KDIn09zdN5fGPJ2 r/7nVs5OvMS8QtKDBtAAJ5gz2qh6JIWt2nhEVODofKmVyAgLf5k8HhB9GIAkWzS33oxP Ie/eMpl6gA+kw1ciTLH0K9f4qVQpX6r264Za2ADsODZegZ03sYMoVjmLz+2j/t6fg8pk 9N6suE80HXdkRVnbp2RAOpNIH8Lr15nMwQiAiRhyQuu53T8QqWcY6OCS+ZuVObwQxVKo xPRxXVyp9HZt0MOMpFTAfWE0neF77yVPdcTrfKeLcISJTvH5BFVPZ/i3OTNV0ud5vJ+d kCiA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:sender:in-reply-to:references:date :message-id:subject:from:to:cc; bh=MB6nZL3xhaWlHrv//pvMDuvaWhVpvOIkiDoAkvkrHrA=; b=TN3EB8z/O7Ko/2POk00F1F+5QCNP35ASwEnwIWOLeXdBMnc8Iq57dozeMofcLLKtLM zNeWI/uQ1OTMtKM+QNkIZqU3aRSbBMfI8VAOadQ3o8qzEC/3H0ES2kGwcj9MR0CJzeuB zi2D3+OZpQytDPmTqepiQQ8IuB853QLlznSjx7Yac6XN+8kXmpj7JGFGsWEmxNaFtfSX 0mqSCbB3Xno+sKbJZvt5BOC3EkNbGwGI+2tA6puMCeu+eRbryEKJPStQm7yWm1Q8n4Bh QKLd7h9dfJ5UjLQAmP61N/ZzWZ+w0d96SyJZ0eqFdZmOgrK7pv4R1eOv5IWKfQG57oW/ Z10Q== X-Gm-Message-State: AOPr4FU50UUnfKK/jIyGZxWFulKSL+QarTqV8Z+6CU/5ME1FM5bTMLVTn/SrELV2Ih5kzOyNMX4NeMOd07beeQ== MIME-Version: 1.0 X-Received: by 10.107.16.137 with SMTP id 9mr41152259ioq.75.1462864676473; Tue, 10 May 2016 00:17:56 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.36.113.3 with HTTP; Tue, 10 May 2016 00:17:56 -0700 (PDT) In-Reply-To: References: <871t5bpkc7.fsf@toke.dk> <6ADC1A9D-72C9-47A5-BDC7-94C14ED34379@gmail.com> Date: Tue, 10 May 2016 00:17:56 -0700 X-Google-Sender-Auth: jbz6SG_bDCVZYGEFW9TTH8DLDk8 Message-ID: From: Adrian Chadd To: Dave Taht Cc: Jonathan Morton , make-wifi-fast@lists.bufferbloat.net, "ath9k-devel@lists.ath9k.org" , =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= Content-Type: text/plain; charset=UTF-8 Subject: Re: [Make-wifi-fast] [ath9k-devel] Diagram of the ath9k TX path 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, 10 May 2016 07:17:56 -0000 The other hack that I've seen ath9k do is they actually assign sequence numbers and CCMP IVs at the point of enqueue-to-hardware, rather than enqueue-to-driver. I tried this in FreeBSD and dropped it for other reasons, mostly in favour of shallower (configurable!) per-station queue depths. That way you /could/ drop data frames in the driver/wifi stack per-STA/TID queues as part of queue discipline, way before it gets sent out on the air. If you're modeling airtime on the fly then you could see the queue for a given station is way too deep now that the rate to it has dropped, so don't bother keeping those frames around. Once you have assigned the seqno/IV then you're "committed" so to speak. -adrian