Return-path: Received: from mail.neratec.com ([46.140.151.2]:41981 "EHLO mail.neratec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751604AbdAaKSL (ORCPT ); Tue, 31 Jan 2017 05:18:11 -0500 Subject: Re: Packet throughput (and those iperf data rate) with mac80211/ath9k is 20% worse than net80211/madwifi To: Klaus Kinski References: <87lgtsjz6o.fsf@toke.dk> <87o9yo2v0s.fsf@toke.dk> Cc: =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , Dave Taht , linux-wireless From: Wojciech Dubowik Message-ID: (sfid-20170131_111924_227785_3DC6B7B8) Date: Tue, 31 Jan 2017 10:52:30 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 31/01/17 10:46, Klaus Kinski wrote: > BTW, if I read the sources correctly, than IBSS mode uses the TXQ > parameters from ieee80211_set_wmm_default with enable_qos = false > which means that qparam.txop = 0, e.g. bursting is disabled. Am I right? I guess so. But you need to look also at contention window sizes because it make a big impact on throughout with retries and collisions. > > Jörg Pommnitz > schrieb > am Di., 31. Jan. 2017 um 10:37 Uhr: > > I'm mostly interested in Ad-Hoc mode, e.g. IBSS. > > Wojciech Dubowik > schrieb am Di., 31. Jan. > 2017 um 10:35 Uhr: > > That's tricky but look at > http://w1.fi/cgit/hostap/tree/hostapd/hostapd.conf > > > tx_queue... are for AP and wmm_... for STA (over beacons). > > These should be default parameters. You can also enable CONFIG > debug flag > > for ath9k and it prints wme parameters when it starts. > > Wojtek > > > On 31/01/17 10:18, Klaus Kinski wrote: >> It seems that bursting can be controlled over nl80211 (see , >> specifically with NL80211_ATTR_WIPHY_TXQ_PARAMS. >> Unfortunately this seems not to be exposed in iw. It's an >> attribute of NL80211_CMD_SET_WIPHY. >> Is there another tool that exposes txq params? If not, has >> anybody thought about exposing it in iw? I might take a stab >> at it... >> >> Regards >> Joerg >> >> Wojciech Dubowik > > schrieb am Di., 31. >> Jan. 2017 um 08:55 Uhr: >> >> Madwifi has default best effort queue "tuned" for throughout >> >> and its parameters are different from mac80211 defaults when >> >> qos (WME) is disabled. >> >> You would have to dump qos settings for both systems before >> >> comparing them. I guess the easiest way is to make sure QoS >> >> is enabled and send video type of packets with iperf ... >> -S 0xa0 >> >> Wojtek >> >> >> On 30/01/17 20:43, Toke Høiland-Jørgensen wrote: >> > Klaus Kinski > > writes: >> > >> >> The captures I used to create the statistics are here: >> >> >> https://drive.google.com/open?id=0ByFGz3ZH6JcYMGp0a05lYzBPNzA >> >> >> >> An obvious difference is, that Madwifi sends 5 packets >> in a row >> >> without waiting for an ACK whereas ath9k/mac80211 >> always seems to wait >> >> for an ACK. This seems to point to the "net80211 >> aggressive mode >> >> theory" https://wiki.freebsd.org/WifiAggressiveMode >> , IMHO. >> > I'm not too familiar with that part of the stack, but >> that seems >> > reasonable, yeah. AFAIK the "aggresive mode" is a >> pre-802.11n feature, >> > though, which is why you won't see that in ath9k. In >> 802.11n this kind >> > of bursting was replaced by aggregation, which you're >> not getting any of >> > since you're running in 802.11a mode, obviously. >> > >> > The lack of bursting will translate to slightly lower >> throughput, which >> > will be why you see fewer packets transmitted by ath9k. >> Of course, if >> > your receiver supported aggregation, the numbers would >> look dramatically >> > better in ath9k's favour... ;) >> > >> > -Toke >>