Return-path: Received: from mail-qk0-f171.google.com ([209.85.220.171]:34489 "EHLO mail-qk0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751822AbdA3Q4X (ORCPT ); Mon, 30 Jan 2017 11:56:23 -0500 Received: by mail-qk0-f171.google.com with SMTP id l126so2647921qkc.1 for ; Mon, 30 Jan 2017 08:56:23 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <87lgtsjz6o.fsf@toke.dk> References: <87lgtsjz6o.fsf@toke.dk> From: Dave Taht Date: Mon, 30 Jan 2017 08:49:30 -0800 Message-ID: (sfid-20170130_175927_292910_977A55AD) Subject: Re: Packet throughput (and those iperf data rate) with mac80211/ath9k is 20% worse than net80211/madwifi To: =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= Cc: Klaus Kinski , linux-wireless Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Mon, Jan 30, 2017 at 8:17 AM, Toke H=C3=B8iland-J=C3=B8rgensen wrote: > Klaus Kinski writes: > >> Hello all, >> >> this is a blast from the past, but something that still bothers me. >> I have two systems with Atheros/QCA cards: >> >> System A: >> OS and driver: Linux 3.18.36 with last Madwifi/sample code from trunk >> >> WLAN card: AR5413 (Senao EMP-8602 PLUS-S) >> >> System B: >> OS and driver: Linux 3.18.36 with mac80211/minstrel and ath9k from bac= kports-4.2 >> >> WLAN card: AR9280 (Compex WLE200NX) >> >> While doing the performance measurements both systems are connected to a= reference system >> >> with a HF cable, so there should be no outside influences. >> >> Both systems are running in 802.11a mode on channel 40. >> The following table shows 802.11 data packets sent from system A and B g= enerated by >> >> iperf in UDP mode over a 2s interval: > > What version of iperf, and configured to which rate? Some versions of > iperf will send its traffic in very large bursts (see > http://burntchrome.blogspot.se/2016/09/iperf3-and-microbursts.html?m=3D1) > which could cause the queue inside ath9k to overflow (it is only 123 > packets pre-4.10). > > Did you try the latest mac80211/ath9k from 4.10? The queueing structure > changed dramatically, which would impact this, at least if it's a queue > overflow problem... Packet captures would be helpful. Aircaps, if possible, also. > -Toke --=20 Dave T=C3=A4ht Let's go make home routers and wifi faster! With better software! http://blog.cerowrt.org