Return-path: Received: from mail-wm0-f43.google.com ([74.125.82.43]:38459 "EHLO mail-wm0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752085AbcCVGvI convert rfc822-to-8bit (ORCPT ); Tue, 22 Mar 2016 02:51:08 -0400 Received: by mail-wm0-f43.google.com with SMTP id l68so149384749wml.1 for ; Mon, 21 Mar 2016 23:51:07 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1458123478-1795-1-git-send-email-michal.kazior@tieto.com> <1458123478-1795-2-git-send-email-michal.kazior@tieto.com> Date: Tue, 22 Mar 2016 07:51:06 +0100 Message-ID: (sfid-20160322_075116_391823_A3F2F0BC) Subject: Re: [Make-wifi-fast] [RFCv2 1/3] mac80211: implement fq_codel for software queuing From: Michal Kazior To: David Lang Cc: linux-wireless , Emmanuel Grumbach , Network Development , "ath10k@lists.infradead.org" , codel@lists.bufferbloat.net, make-wifi-fast@lists.bufferbloat.net, Johannes Berg , Tim Shepard Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 22 March 2016 at 02:35, David Lang wrote: > On Wed, 16 Mar 2016, Michal Kazior wrote: > >> Since 11n aggregation become important to get the >> best out of txops. However aggregation inherently >> requires buffering and queuing. Once variable >> medium conditions to different associated stations >> is considered it became apparent that bufferbloat >> can't be simply fought with qdiscs for wireless >> drivers. > > If the network is quiet enough, don't do any buffering, but in almost all > situations you are going to need to buffer starting no later than the second > packet you try to send. > > Don't try to make queueing occur, just deal with the queues that form > naturally because you can't transmit data any faster (and work to keep them > under some semblence of control) [...] This is what already happens. Queues typically start to build up when hardware tx fifos/queues become busy so by the time they become available you might have a bunch of frames you can aggregate. The patch is more about getting rid of qdiscs because it's inherently hard to teach them how 802.11 aggregation works (per-station per-tid) and the ever-changing nature of per-station tx conditions. I'll update the commit log to better reflect what is being done. Michał