Return-path: Received: from mail2.candelatech.com ([208.74.158.173]:42546 "EHLO mail2.candelatech.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751123AbdAaPcm (ORCPT ); Tue, 31 Jan 2017 10:32:42 -0500 Message-ID: <5890ACA8.3010403@candelatech.com> (sfid-20170131_163258_634209_0B3368ED) Date: Tue, 31 Jan 2017 07:26:32 -0800 From: Ben Greear MIME-Version: 1.0 To: Wojciech Dubowik , Klaus Kinski CC: =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= , Dave Taht , linux-wireless Subject: Re: Packet throughput (and those iperf data rate) with mac80211/ath9k is 20% worse than net80211/madwifi References: <87lgtsjz6o.fsf@toke.dk> <87o9yo2v0s.fsf@toke.dk> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: One thing to consider: Older ath9k and maybe madwifi used a different congestion control, and it got higher throughput in optimal situations in our testing. When it was removed from the kernel, there was some effort to improve the minstrel_ht algorithm, but I don't think it ever performed quite as well as far as bulk transfer is concerned. Thanks, Ben On 01/31/2017 01:52 AM, Wojciech Dubowik wrote: > > > 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 >>> > -- Ben Greear Candela Technologies Inc http://www.candelatech.com