Return-path: Received: from mail-ob0-f174.google.com ([209.85.214.174]:58262 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754432Ab2FZMV5 (ORCPT ); Tue, 26 Jun 2012 08:21:57 -0400 Received: by obbuo13 with SMTP id uo13so7953113obb.19 for ; Tue, 26 Jun 2012 05:21:56 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1340712536.14634.13.camel@jlt3.sipsolutions.net> References: <1340712213-10193-1-git-send-email-eyal@wizery.com> <1340712536.14634.13.camel@jlt3.sipsolutions.net> From: Eyal Shapira Date: Tue, 26 Jun 2012 15:21:36 +0300 Message-ID: (sfid-20120626_142210_814741_AC354329) Subject: Re: [PATCH] mac80211: use legacy mode for all ACs To: Johannes Berg Cc: linux-wireless@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 26 June 2012 15:08, Johannes Berg wrote: > > On Tue, 2012-06-26 at 15:03 +0300, Eyal Shapira wrote: > > AVM FritzBox 7390 has a weird behaviour where once we enable > > U-APSD only on the VO AC it limits the rate of the packets > > it sends to 39Mbps and doesn't do AMPDU aggregation. > > This causes a big degradation in throughput obviously. > > It's important to note that this isn't related to PS and happens > > also when ACTIVE is forced. The traffic affected is sent in BE AC. > > Once legacy mode for all ACs is used the AP begins using higher rates > > as well as AMPDU aggregation which improves throughput significantly. > > > > In order to deal with this AP and potentially others switch to > > using legacy mode for all ACs by default. > > This actually somewhat makes sense if they have a bad aggregation > implementation, because you don't want VO to have latency, *especially* > not when uAPSD was enabled, indicating that you want VO-like low-latency > behaviour. > > I don't see why you're optimising for TPT on VO rather then latency? > The problem is that when we're requesting uAPSD on VO it messes up with traffic sent on the BE AC which isn't supposed to get affected but it does (probably a bug). The effect is that any traffic we're doing gets very low TPT. Apparently this AP is quite common in Germany and other places so we can't just ignore it. I was thinking that if someone wants uAPSD on the VO they can still set it from userspace through the nl80211. > > johannes >