Return-path: Received: from mail-pa0-f48.google.com ([209.85.220.48]:32995 "EHLO mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754925AbcIKDQ7 (ORCPT ); Sat, 10 Sep 2016 23:16:59 -0400 Received: by mail-pa0-f48.google.com with SMTP id cm16so40505329pac.0 for ; Sat, 10 Sep 2016 20:16:59 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <20160910193315.30738-1-toke@toke.dk> From: Loganaden Velvindron Date: Sun, 11 Sep 2016 07:16:58 +0400 Message-ID: (sfid-20160911_051705_160244_4E9D1421) Subject: Re: [Make-wifi-fast] [PATCH] mac80211: Dynamically set CoDel parameters per station. To: Jim Gettys Cc: =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= , make-wifi-fast@lists.bufferbloat.net, linux-wireless , Felix Fietkau Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Sat, Sep 10, 2016 at 11:54 PM, Jim Gettys wrote: > > > On Sat, Sep 10, 2016 at 3:33 PM, Toke H=C3=B8iland-J=C3=B8rgensen > wrote: >> >> CoDel can be too aggressive if a station sends at a very low rate, >> leading to starvation. This gets worse the more stations are present, as >> each station gets more bursty the longer the round-robin scheduling >> between stations takes. >> >> This adds dynamic adjustment of CoDel parameters per station. It uses >> the rate selection information to estimate throughput and sets more >> lenient CoDel parameters if the estimated throughput is below a >> threshold. To not change parameters too often, a hysteresis of two >> seconds is added. > > > Where is this 2 second constant coming from? I'd expect it should be of > order the maximum RTT (or a small constant factor of that, which for > intercontinental connections should be 200-300ms. > Indeed, from Mauritius (Africa) to remote countries like Australia, or parts of the US, we see latencies of up to 500-600ms.